Physical World/Biology

Biochemistry

Adenosine – a molecule of adenine attached to a ribose sugar molecule

Adenosine diphosphate (ADP) – an important organic compound in metabolism and is essential to the flow of energy in living cells

Amino acids – organic compounds containing an amine group and a carboxylic acid group. 20 in total, 8 of which are essential: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine

Adenosine triphosphate (ATP) – an adenosine-derived nucleotide that contains high-energy phosphate bonds and is used to transport energy to cells for biochemical processes. Energy can be stored by adding a phosphate group onto an ADP molecule, turning it into ATP. Energy is released by breaking down ATP into ADP

Bicarbonate (HCO₃⁻) is alkaline, and a vital component of the pH buffering system of the human body

Calvin cycle – (or Calvin-Benson cycle or carbon fixation) is a series of biochemical reactions that takes place in the stroma of chloroplasts in photosynthetic organisms. The light-independent Calvin cycle uses the energy from short-lived electronically excited carriers to convert carbon dioxide and water into organic compounds that can be used by the organism. This set of reactions is also called carbon fixation. The key enzyme of the cycle is called RuBisCO. Andrew Benson used radioactive carbon dioxide to study how plant makes sugars using carbon. He received no credit for his work from Melvin Calvin

Carbohydrate – an organic compound with the empirical formula C_m(H₂O)_n, that is, consists only of carbon, hydrogen and oxygen, with the last two in the 2:1 atom ratio

Catalyst – a substance, usually used in small amounts relevant to the reactants that modifies and increases the rate of a reaction without being consumed in the process

Cellular respiration – also known as oxidative metabolism, is one of the key ways a cell gains useful energy. It is the set of the metabolic reactions and processes that take place in cells to convert biochemical energy from nutrients into ATP, and then release waste products

Chemiosmosis – the movement of ions across a selectively permeable membrane, down their electrochemical gradient. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration

Chemosynthesis – the biological conversion of one or more carbon molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic molecules (e.g. hydrogen gas, hydrogen sulfide) or methane as a source of energy, rather than sunlight, as in photosynthesis

Chlorophyll – has a magnesium ion at the centre of the chlorine ring

Cholesterol – a waxy steroid metabolite found in the cell membranes and transported in the blood plasma of all animals. It is an essential structural component of mammalian cell membranes, where it is required to establish proper membrane permeability and fluidity. In addition, cholesterol is an important component for the manufacture of bile acids, steroid hormones, and some vitamins. Cholesterol is a lipid. C₂₇H₄₆O

Citric acid cycle – also known as the tricarboxylic acid cycle (TCA cycle), or the Krebs cycle, is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate into carbon dioxide and chemical energy in the form of ATP. It produces carbon dioxide as a waste byproduct. In eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion

Codon – a sequence of three adjacent nucleotides constituting the genetic code that determines the insertion of a specific amino acid in a polypeptide chain during protein synthesis

Cofactor – a non-protein chemical compound that is bound to a protein and is required for the protein's biological activity. These proteins are commonly enzymes, and cofactors can be considered ‘helper molecules’ that assist in biochemical transformations. Coenzyme is a type of cofactor

Deoxyribonucleic acid (DNA) – has a backbone made of alternating sugars (deoxyribose) and phosphate groups (related to phosphoric acid), with the nucleobases (Guanine, Adenine, Thymine, Cytosine) attached to the sugars. Double helix structure

DNA ligase – a specific type of enzyme, a ligase, that facilitates the joining of DNA strands together

DNA sequencing – the process of determining the nucleotide order of a given DNA fragment. Thus far, most DNA sequencing has been performed using the chain termination method developed by Frederick Sanger

DNA bases – always read in threes. If one or two bases are inserted or deleted, this leads to frameshift, an alteration in the reading pattern, and to a mutation

Denaturation – a process in which proteins or nucleic acids lose their structure by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), or heat

Directionality – the end-to-end chemical orientation of a single strand of nucleic acid. The chemical convention of naming carbon atoms in the nucleotide sugar-ring numerically gives rise to a 5′-end and a 3′-end (usually pronounced ‘five prime end’ and ‘three prime end’). The relative positions of structures along a strand of nucleic acid, including genes and various protein binding sites, are usually noted as being either upstream (towards the 5′-end) or downstream (towards the 3′-end)

Electrochemical gradient – a gradient of electrochemical potential, usually for an ion that can move across membrane. The gradient consist of two parts, the electrical potential and a difference in the chemical concentration across a membrane. The difference of electrochemical potentials can be interpreted as a type of potential energy available for work in a cell

Electron transport chain – couples electron transfer between an electron donor (such as NADH) and an electron acceptor (such as O₂) with the transfer of H⁺ ions (protons) across a membrane. The resulting electrochemical proton gradient is used to generate chemical energy in the form of ATP. Electron transport chains are the cellular mechanisms used for extracting energy from sunlight in photosynthesis and also from redox reactions, such as the oxidation of sugars (respiration)

Electrophoresis – the movement of electrically charged particles in a liquid or gas that is under the influence of an electric field. Gel electrophoresis is used to separate molecules of DNA or protein

Enzyme – from Greek for ‘yeast’. A protein produced by living organisms that acts as a catalyst in chemical reactions. Enzymes catalyze (i.e. increase the rates of) chemical reactions. In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products

Enzyme – term coined in 1878 by German physiologist Wilhelm Kuhne. An enzyme's name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in –ase. The active site of an enzyme is the binding site where catalysis occurs. Most enzymes are proteins. Enzymes are classified by Enzyme Commission number (EC number)

Ferritin – intracellular protein that stores iron and releases it in a controlled fashion

Fructose – an isomer of glucose; i.e., both have the same molecular formula (C₆H₁₂O₆) but they differ structurally

Glucose – also known as grape sugar and dextrose. C₆H₁₂O₆

One molecule of glucose produces 38 ATPs

Glutamic acid – a non-essential amino acid. It is often used as a food additive and flavour enhancer in the form of its sodium salt, monosodium glutamate (MSG)

Glycerophospholipids – or phosphoglycerides are glycerol-based phospholipids. They are the main component of biological membranes

Glycogen – a polysaccharide of glucose, that is the main form of carbohydrate storage in animals and occurs primarily in the liver and muscles. C₆ H₁₀ O₅

Glycolysis – the metabolic pathway that converts glucose into pyruvate. The free energy released in this process is used to form the high-energy compounds ATP and NADH. Uses 2 ATPs but produces 4 ATPs. Glycolysis occurs in cytoplasm

Heterosaccharide – a glycoside in which a sugar (saccharide) group is attached to a nonsugar group

Immunoassay – a biochemical test that measures the presence or concentration of a substance in solutions that frequently contain a complex mixture of substances. Such assays are based on the unique ability of an antibody to bind with high specificity to one or a very limited group of molecules

Lactose – sugar found in milk, which the body breaks down into galactose and glucose

Lipase – a water-soluble enzyme that catalyzes the hydrolysis of ester bonds in water–insoluble, lipid substrates

Maillard reaction – a chemical reaction between amino acids and reducing sugars that gives browned foods their desirable flavour

Messenger RNA (mRNA) – carries information about a protein sequence to the ribosomes, the protein synthesis factories in the cell

Monosaccharides – the simplest form of carbohydrates. They consist of one sugar and are usually colourless, water-soluble, crystalline solids. Examples of monosaccharides include glucose (dextrose), fructose, galactose, and ribose. Monosaccharides are the building blocks of disaccharides like sucrose (common sugar) and polysaccharides (such as cellulose and starch)

Motor proteins – a class of molecular motors that are able to move along the surface of a suitable substrate. They are powered by the hydrolysis of ATP and convert chemical energy into mechanical work

Nicotinamide adenine dinucleotide (NAD) – a coenzyme found in all living cells. The compound is a dinucleotide, because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine base and the other nicotinamide. Nicotinamide adenine dinucleotide exists in two forms, an oxidized and reduced form abbreviated as NAD⁺ and NADH respectively. NAD is involved in redox reactions

Nicotene – C₁₀H₁₄N₂. Alkaloid found in the nightshade family of plants

Noncoding DNA – describes components of an organism's DNA sequences that do not encode for protein sequences. Much of this DNA has no known biological function (c. 97%) and at one time was sometimes referred to as ‘junk DNA’

The central dogma of molecular biology is the statement that genetic information resides in the nucleic acid (DNA and RNA) and passes to the protein sequence, but cannot flow from protein to protein or back to nucleic acid. It was first articulated by Francis Crick in 1958 and re-stated in a Nature paper published in 1970

Nucleosides – compounds of purine or pyrimidine bases with a sugar, most commonly ribose. For example, adenine plus ribose forms adenosine. With the addition of phosphate a nucleotide is formed

Nucleotide – a sugar (ribose or deoxyribose), a phosphate group, and one of four bases

Oxidative phosphorylation – the metabolic pathway in which the mitochondria in cells use their structure, enzymes, and energy released by the oxidation of nutrients to reform ATP

Oxygenic photosynthesis – the process which splits water molecules creating oxygen as a by-product

Pectin – a white to light brown powder, is a heterosaccharide derived from the cell wall of higher terrestrial plants. It is mainly used in food as a gelling agent in jams and jellies

Peptide – a short chain of amino acid monomers linked by peptide bonds

Phenylalanine – an amino acid found naturally in the breast milk of mammals. It is used in the manufacture of food and drink products and sold as a nutritional supplement for its reputed analgesic and antidepressant effects. Also found in aspartame

Phospholipids – a class of lipids that are a major component of all cell membranes as they can form lipid bilayers

Phosphorylation – the addition of a phosphate group to a protein or other organic molecule. The phosphorylation of ADP to form ATP using the energy of sunlight is called photophosphorylation

Photorespiration – attempts to ameliorate the consequences of a wasteful oxygenation reaction by the enzyme RuBisCO. The desired reaction is the addition of carbon dioxide to RuBP (carboxylation), a key step in the Calvin-Benson cycle, however approximately 25% of reactions by RuBisCO instead add oxygen to RuBP (oxygenation)

Plasmid – circular, double-stranded unit of DNA that replicates within a cell independently of the chromosomal DNA. Most commonly found in bacteria

Polymerase chain reaction (PCR) – a technique in molecular biology to amplify a single or few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence

Polysaccharides – polymeric carbohydrate structures, formed of repeating units (either mono- or di-saccharides) joined together by glycosidic bonds. Examples include storage polysaccharides such as starch and glycogen, and structural polysaccharides such as cellulose and chitin

Proteasomes – protein complexes inside all eukaryotes and archaea. The main function of the proteasome is to degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds. Enzymes that carry out such reactions are called proteases

Proteins – organic compounds made of amino acids arranged in a linear chain and folded into a globular form. The amino acids in a polymer are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues

Protein folding – the physical process by which a polypeptide folds into its characteristic and functional three-dimensional structure

Protein synthesis – a universal function whereby mRNA molecules direct the assembly of proteins on ribosomes. This process uses transfer RNA (tRNA) molecules to deliver amino acids to the ribosome, where ribosomal RNA (rRNA) links amino acids together to form proteins

Purines – adenine and guanine

Pyridamines – thymine and cytosine

Pyruvic acid (pyruvate) – supplies energy to living cells through the Krebs cycle when oxygen is present

Recombination – a process by which a molecule of nucleic acid (usually DNA, but can also be RNA) is broken and then joined to a different one

Recombinant DNA (rDNA) is an artificial DNA sequence resulting from the combination of different DNA sequences. The name comes from the process, which ‘recombines’ DNA from two or more disparate sources

Replication – the process of duplicating or reproducing, as the replication of an exact copy of a polynucleotide strand of DNA or RNA

Restriction enzyme – an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. Provide a defense mechanism against invading viruses

Reverse transcriptase – a DNA polymerase enzyme that transcribes single-stranded RNA into single-stranded DNA

Ribonucleic acid (RNA) – a nucleic acid polymer that acts as a messenger between DNA and ribosomes, and that is also responsible for making proteins out of amino acids. RNA polynucleotides contain ribose sugars and predominantly uracil, unlike DNA, which contains deoxyribose and predominantly thymine. It is transcribed (synthesized) from DNA by enzymes called RNA polymerases. RNA serves as the template for translation of genes into proteins, transferring amino acids to the ribosome to form proteins, and also translating the transcript into proteins

RNA interference (RNAi) – a process in which RNA molecules inhibit gene expression, typically by causing the destruction of specific mRNA molecules

Ribose – C₅H₁₀O₅

Ribosomal RNA (rRNA) – the RNA component of the ribosome, and is essential for protein synthesis in all living organisms. It constitutes the predominant material within the ribosome

RuBisCO – an enzyme involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is converted by plants to energy-rich molecules such as glucose. It is probably the most abundant protein on Earth

Saturated fat – consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the individual carbon atoms of the fatty acid chain

Starch – a carbohydrate consisting of a large number of glucose units joined by glycosidic bonds

Substrate – a molecule upon which an enzyme acts. Enzymes catalyze chemical reactions involving the substrate. Both the enzyme and the substrate possess specific complementary geometric shapes that fit exactly into one another. This is often referred to as ‘the lock and key’ model

Sucrose – the chemical name of table sugar. Sucrose is a disaccharide; each molecule consists of two ‘simple’ sugars (a glucose and a fructose). C₁₂H₂₂O₁₁

Sequence – the order in which subunits appear in a chain, such as amino acids in a polypeptide or nucleotide bases in a DNA or RNA molecule

Shotgun sequencing – also known as shotgun cloning, is a method used for sequencing long DNA strands

Southern blot – a method routinely used in molecular biology to check for the presence of a DNA sequence in a DNA sample. The method is named after its inventor, the British biologist Edwin Southern. Other blotting methods (i.e., Western blot, Northern blot, Eastern blot) that employ similar principles, but using RNA or protein, have later been named in reference to Edwin Southern's name. A blot is a method of transferring proteins, DNA or RNA, onto a carrier

Telomerase – an enzyme that adds DNA sequence repeats to the 3' end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes

Theanine – an amino acid which is a derivative of glutamine. It is commonly found in tea and can produce a feeling of relaxation

Transcription – the process through which a DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA, ie the transfer of genetic information from DNA into RNA. Transcription results in an RNA complement that includes uracil in all instances where thymine would have occurred in a DNA complement

Transduction – the process by which DNA is transferred from one bacterium to another by a virus. It also refers to the process whereby foreign DNA is introduced into another cell via a viral vector

Transfer RNA (tRNA) – a small RNA chain of about 80 nucleotides that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation

Translation – the process by which messenger RNA directs the amino acid sequence of a growing polypeptide during protein synthesis

Transversion – the substitution of a purine for a pyrimidine or vice versa

Triglyceride – a glyceride in which the glycerol is esterified with three fatty acids

Terpenes – a large and varied class of organic compounds, produced primarily by a wide variety of plants, particularly conifers. They are the major components of resin, and of turpentine produced from resin

Tryptophan – an essential amino acid. A precursor to serotonin and niacin, and is particularly found in eggs, fish and dairy products

Unsaturated fat – a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fat molecule is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond. Where double bonds are formed, hydrogen atoms are eliminated

Urea cycle – a cycle of biochemical reactions occurring in many animals that produces urea from ammonia. This cycle was the first metabolic cycle discovered (Hans Krebs and Kurt Henseleit, 1932). In mammals, the urea cycle takes place primarily in the liver

Zymogen – (or proenzyme) is an inactive enzyme precursor. A zymogen requires a biochemical change for it to become an active enzyme

Zoology, Ecology and Taxonomy

Acidophiles – species that live in areas of low pH

Ambergris – a solid, waxy, flammable substance produced in the digestive system of sperm whales

Amplexus (Latin ‘embrace’) is a form of pseudocopulation found chiefly in amphibians and horseshoe crabs in which a male grasps a female with his front legs as part of the mating process. The male sheds sperm onto eggs as they emerge from the female’s body

Ampullae of Lorenzini – special sensing organs called electroreceptors, forming a network of jelly-filled canals. They are mostly discussed as being found in cartilaginous fishes. These sensory organs help fish to sense electric fields in the water

Anadromous – migrating up rivers from the sea to breed in fresh water

Anisodactyly is the most common arrangement of digits in birds, with three toes forward and one back

Apex predators (also known as alpha-, super-, top- or top-level predators) are predators with no predators of their own, residing at the top of their food chain

Apophallation – a technique resorted to by some species of air-breathing land slugs. After mating, if the slugs cannot successfully separate, a deliberate amputating of the penis takes place

Aptery – the anatomical condition of an animal completely lacking any kind of wings. An animal with this condition is said to be apterous

Archaea – any of various single-celled prokaryotes genetically distinct from bacteria. Often metabolize hydrogen or sulphur, and cannot tolerate oxygen. Archaeal membranes are made of molecules that differ strongly from those in other life forms, showing that archaea are related only distantly to bacteria and eukaryotes

Autecology – the study of the ecology of an individual species

Autotomy or self amputation is the behaviour whereby an animal sheds or discards one or more of its own appendages, usually as a self-defense mechanism to elude a predator's grasp

Baculum – a bone found in the penis of most mammals. The oosik of Native Alaskan cultures is a polished and sometimes carved baculum of various large northern carnivores such as walruses. The word baculum originally meant ‘stick’ or ‘staff’ in Latin. The homologue to the baculum in female mammals is known as the baubellum

Barophiles – species that live in areas of high pressure

Batrachology – he study of amphibians

Benthic – organisms which live at the bottom of the ocean

Binary fission – the form of asexual reproduction and cell division used by all prokaryotes, some protozoa, and some organelles within eukaryotic organisms. This process results in the reproduction of a living cell by division into two parts which each have the potential to grow to the size of the original cell

Bioluminescence – the production of light by living organisms

Brachiation – a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms

Brachiopods – a phylum of marine animals that have hard ‘valves’ (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs

Brood parasites are organisms that use a kind of kleptoparasitism found among birds, fish or insects, involving the manipulation and use of host individuals either of the same or different species to raise the young of the brood-parasite

Brumation – an example of dormancy in reptiles that is similar to hibernation

Carapace – in crustaceans, the part of the exoskeleton that covers the cephalothorax. It is particularly well developed in lobsters and crabs. In turtles and tortoises, the underside is called the plastron

Carnassials – large teeth found in many carnivorous mammals, used for shearing flesh and bone in a scissor- or shear-like way

Carrying capacity of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment

Catadromous – migrating down rivers from the sea to breed

Caudal – a body part located towards an animal’s tail or hindquarters

Biosphere – the part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life. The biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, hydrosphere and atmosphere

Cannon bones – in a horse’s leg

Carbon cycle – the process by which carbon (in the form of carbon dioxide) is absorbed from the atmosphere during photosynthesis, transferred from one organism to another and eventually released back into the atmosphere

Centre of origin – a geographical area where a group of organisms, either domesticated or wild, first developed its distinctive properties

Chimera – an animal that has two or more different populations of genetically distinct cells that originated in different zygotes involved with sexual reproduction; if the different cells emerged from the same zygote, it is called a mosaicism. Chimeras are formed from four parent cells (two fertilized eggs or early embryos fused together)

Chordata – comprises true vertebrates and animals having a notochord, a dorsal nerve cord and gill slits

Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates

Chytridiomycosis is an infectious disease of amphibians, caused by the chytrid Batrachochytrium dendrobatidis, a fungus. Chytridiomycosis has been linked to dramatic population declines or even extinctions of amphibian species

Cilium – (plural: cilia) a short, microscopic, hairlike vibrating structure

Cladistics – a method of classifying species of organisms into groups called clades, which consist of 1) all the descendants of an ancestral organism and 2) the ancestor itself, i.e. evolutionary trees. Cladistics originated in the work of the German entomologist Willi Hennig, who referred to it as phylogenetic systematics

Clade – a group consisting of a species (extinct or extant) and all its descendants. In the terms of biological systematics, a clade is a single ‘branch’ on the ‘tree of life’. Term coined by Julian Huxley

Cladogram – a diagram used in cladistics which shows relations among organisms

Climax community – a historic term that expressed a biological community which, through the process of ecological succession had reached a steady state

Cloaca – the posterior opening that serves as the only such opening for the intestinal, urinary, and (usually) genital tracts of certain animal species. The word comes from Latin, and means ‘sewer’. All birds, reptiles, and amphibians possess this orifice

Cloven hoof – a hoof split into two toes. This is found on members of the mammalian order Artiodactyla

Cnidocyte – an explosive cell containing one giant secretory organelle. A cnidocyte fires a structure that contains the toxin, from a characteristic sub-cellular organelle called a cnidocyst (also known as a cnida or nematocyst). This is responsible for the stings delivered by jellyfish

Coelom – the main body cavity of most higher multicellular animals

Commensalism – a symbiotic relationship between two organisms of different species in which one derives some benefit while the other is unaffected

Competition – in ecology, the interaction between two or more organisms, or groups of organisms, that use a common resource in short supply

Competitive exclusion principle, sometimes referred to Gause's law, states that two species competing for the same resources cannot coexist if other ecological factors are constant

Coral bleaching – the loss of intracellular endosymbionts (zooxanthellae) through either expulsion or loss of algal pigmentation

Cephalothorax (called prosoma in some groups) – an anatomical term used in arachnids and crustaceans for the first (anterior) major body section. The remainder of the body is the abdomen

Chromatophores – pigment-containing and light-reflecting cells found in amphibians, fish, reptiles, crustaceans, and cephalopods. They allow an octopus to change colour

Chromoplasts are plastids responsible for pigment synthesis and storage

Cranial – toward the head end of the body

Crop – between oesophagus and stomach, in a bird

Cuticle forms the outer skeleton of arthropods, including insects

Demersal fish live and feed on or near the bottom of seas or lakes (the demersal zone)

Detritivore – a heterotroph that obtain nutrients by consuming detritus

Diazotrophs – bacteria and archaea that fix atmospheric nitrogen gas into a more usable form such as ammonia

Diptera – insects with a single pair of wings

Distal – the part of an organ or limb that is furthest from the attachment to the body

Division – a biological classification for plants or fungi, equivalent to phylum

Domain – classification above Kingdom, includes some bacteria. There are several modern alternative domain classifications of life. Among them are: The two-empire system, the six-kingdom system (including fungi and protista), and the most recent, the three-domain system of Carl Woese (1990) that divides cellular life forms into archaea, bacteria, and eukaryote domains. In particular, it emphasizes the separation of prokaryotes into two groups, originally called Eubacteria (now Bacteria) and Archaebacteria (now Archaea)

Ecdysis – shedding skin

Ecological pyramid – (also trophic pyramid or energy pyramid) is a graphical representation designed to show the biomass or biomass productivity at each trophic level in a given ecosystem

Ecology – term was first coined by the German biologist Ernst Haeckel in 1866, who defined it as ‘the comprehensive science of the relationship of the organism to the environment.’ The first significant textbook on the subject was written by the Danish botanist, Eugenius Warming. For this early work, Warming is sometimes identified as the founder of ecology

Ectothermic – cold-blooded

Edentate – lacking teeth. Of or belonging to the order Edentata, which includes mammals having few or no teeth, such as anteaters

Endothermic – warm-blooded

Entomophily is a form of pollination whereby pollen is distributed by insects, particularly bees, lepidoptera (e.g. butterflies and moths), flies and beetles

Ethology – study of animal behaviour

Eukaryote – an organism with a complex cell or cells, in which the genetic material is organized into a membrane-bound nucleus or nuclei. Eukaryotes comprise animals, plants, and fungi

Eusociality, the highest level of organization of animal sociality, is defined by the following characteristics: cooperative brood care (including brood care of offspring from other individuals), overlapping generations within a colony of adults, and a division of labour into reproductive and non-reproductive groups

Eutrophication – the ecosystem response to the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system. One example is the ‘bloom’ of phytoplankton in a water body as a response to increased levels of nutrients. Negative environmental effects include hypoxia

Extremophile – an organism that thrives in physically or geochemically extreme conditions that are detrimental to most life on Earth. The domain Archaea contains renowned examples, but extremophiles are present in numerous and diverse genetic lineages of bacteria and archaeans

Fetlock – colloquially referred to as an ‘ankle’. Hinge joint between the cannon bone and the pastern

Flagellum – a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and functions in locomotion

Folivore – a herbivore that specializes in eating leaves

Furcula – wishbone in birds

Gestation periods – mouse 19 days, rat 22 days, rabbit 31 days, dog 61 days, cat 63 days, human 267 days, camel 406 days, elephant 645 days. Alpine black salamander has the longest gestation period, up to 38 months

Gizzard – a specialized stomach constructed of thick, muscular walls is used for grinding up food, often aided by particles of stone or grit

Halteres – small knobbed structures modified from the hindwings in some two-winged insects. They are flapped rapidly and function as gyroscopes

Frogs are known for their three-chambered heart, which they share with all tetrapods except birds and mammals. In the three-chambered heart, oxygenated blood from the lungs and de-oxygenated blood from the respiring tissues enter by separate atria, and are directed via a spiral valve to the appropriate vessel – aorta for oxygenated blood and pulmonary artery for deoxygenated blood

Haemocyanin – proteins that transports oxygen throughout the bodies of some invertebrate animals. Contains two copper atoms. Octopus blood contains the copper-rich protein hemocyanin for transporting oxygen. Horseshoe crab blood, which has haemocyanin rather than haemoglobin, is used to test drugs and implants for endotoxins

Helminthology – study of worms

Hematophagy – feeding on the blood of humans and other warm-blooded hosts

Hemipenes – in lizards and snakes, males possess paired hemipenes, each of which is usually grooved to allow sperm transport and spiny or rough at the tip to allow firm attachment to the female. To become erect, a hemipenis is evaginated (turned inside out) through muscle action and engorgement with blood. Only one is inserted into the female's cloaca at a time

Heterotroph – an organism that cannot fix carbon and uses organic carbon for growth

Holometabolism, also called complete metamorphism, is a term applied to insect groups to describe the specific kind of insect development which includes four life stages – as an embryo or egg, a larva, a pupa and an imago or adult

Homeotherm – an organism that maintains a stable internal body temperature. Most homeotherms are endothermic

Homeothermic – maintaining a steady temperature, synonymous with warm-blooded

Imprinting – a rapid learning process by which a newborn or very young animal establishes a behaviour pattern of recognition and attraction towards other animals of its own kind, as well as to specific individuals of its species, such as its parents, or to a substitute for these

Indicator species – any biological species that defines a trait or characteristic of the environment

Invertebrate trachea – the open respiratory system composed of spiracles, tracheae, and tracheoles that terrestrial arthropods have to transport metabolic gases to and from tissues

Keel – or carina is an extension of the sternum (breastbone) which runs axially along the midline of the sternum and extends outward, perpendicular to the plane of the ribs. The keel provides an anchor to which a bird's wing muscles attach, thereby providing adequate leverage for flight

Keystone species – species that has a disproportionate effect on its environment relative to its biomass. Such species plays a critical role in maintaining the structure of an ecological community

Kleptoparasitism – a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food

Iteroparous species – characterized by multiple reproductive cycles over the course of its lifetime

Lateral – a body part located towards an animal’s side

Livebearers – fish that retain the eggs inside the body and give birth to live, free-swimming young, e.g. guppies

Luciferase – a generic term for the class of enzymes used in bioluminescence. One example is the firefly luciferase

Mammal – any warm-blooded vertebrate having the skin more or less covered with hair

Mantle – an organ found in molluscs. It is the dorsal body wall covering the main body, or visceral mass. In many species, the epidermis of this organ secretes calcium carbonate to create a shell

Marsupial – mammals of which the females have a pouch (the marsupium)

Meconium – the red fluid that butterflies and moths eject after they leave the chrysalis. Meconium is a metabolic waste product from the pupal stage that is expelled through the anal opening

Merkel cells – oval receptor cells found in the skin of vertebrates

Mesophile – an organism that grows best in moderate temperature

Molera – a ‘hole’ in a chihuahua's head; it is the same as a fontanelle in human babies

Monophyletic group – a taxon (group of organisms) which forms a clade, meaning that it consists of an ancestral species and all its descendants

Morphogenesis – the biological process that causes an organism to develop its shape

Mutualism – symbiosis which is beneficial to both organisms involved

Nekton – free swimming organisms, any size up to whales

Neutrophile is an organism that thrives in neutral pH environments

Niche – place or function of a given organism within its ecosystem

Nictitating membrane – third eyelid, in many animals

Nitrification – the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates

Nitrogen cycle – the continuous circulation of nitrogen and its compounds between the Earth and its atmosphere, resulting from the activity of living organisms.  Involves nitrogen fixation, decay, nitrification and denitrification

Nitrogen fixation – the process by which nitrogen is taken from its relatively inert molecular form (N₂) in the atmosphere and converted into nitrogen compounds (such as, notably, ammonia, nitrate and nitrogen dioxide) useful for other chemical processes

Notochord – a flexible rodlike structure that forms the main support of the body in the lowest chordates, such as the lancelet; a primitive backbone; a similar structure in embryos of higher vertebrates, from which the spinal column develops

Obligate parasite – a parasitic organism that cannot complete its life cycle without exploiting a suitable host

Ocelli – simple eyes. Found in spiders, bees, jellyfish

Oligotrophic – environments that offer little to sustain life, organisms that survive in such environments, or the adaptations that support survival

Ommatidia – compound eyes of insects, mantis shrimp and millipedes

Ommatophore – a movable stalk ending with an eye, as found in certain snails

Operculum – a structure that closes or covers an aperture, e.g. a gill cover

Ophiology – study of snakes

Oral disc – the flattened upper or free end of the body of a polyp that has the mouth in the centre and tentacles around the margin

Osmeterium – a fleshy organ found in the prothoracic segment of larvae (caterpillars) of Swallowtail butterflies. This organ emits smelly compounds believed to be pheromones

Ossicones are horn-like (or antler-like) protuberances on the heads of giraffes and male okapis

Oviparous – animals that lay eggs

Ovipositor – an organ used by some animals for oviposition, i.e. the laying of eggs

Parasites – that live on the surface of the host are called ectoparasites (e.g. some mites). Those that live inside the host are called endoparasites (including all parasitic worms). An epiparasite is one that feeds on another parasite

Parasitoid – an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host, e.g the ichneumon wasp

Paraphyletic group – consists of all the descendants of the last common ancestor of the group's members minus a small number of monophyletic groups of descendants

Parietal eyes – are found in lizards, tuataras, frogs and lampreys, as well as some species of fish, such as tuna and pelagic sharks, where it is visible as a light-sensitive spot on top of their head. The eye is photoreceptive and is associated with the pineal gland

Parotoid gland – an external skin gland on toads and some frogs and salamanders. It secretes a milky alkaloid substance to deter predators. The substance, bufotoxin, acts as a neurotoxin

Parthenogenesis – a form of reproduction in which an unfertilized egg develops into a new individual. Parthenogenetic offspring in species that use either the XY or the X0 sex-determination system have two X chromosomes and are female

Pastern – a part of the horse between the fetlock joint and the hoof, or between the wrist and forepaw of a dog

Patagium – a membranous structure that assists an animal in gliding or flight

Perissodactyl – having an uneven number of toes. Of or relating to certain hoofed mammals, such as horses and rhinoceroses

Phenology – study of periodic biological phenomena, such as flowering, breeding, and migration, in relation to climatic conditions

Pheromone – male butterflies and moths emit an airborne trail of a specific chemical blend constituting that species' sex pheromone. This aerial trail is referred to as a pheromone plume. Males of that species use the information contained in the pheromone plume to locate the emitting female (known as a ‘calling’ female)

Poikilotherm – an organism whose internal temperature varies considerably. Many terrestrial ectotherms are poikilothermic

Polymorphism – the occurrence of different forms, stages, or types in individual organisms or in organisms of the same species

Potodromous – a life history strategy in which a species of fish completes its entire life cycle in freshwater including growing, maturing and spawning

Precocial – refers to species in which the young are relatively mature and mobile from the moment of birth or hatching. The opposite developmental strategy is called altricial where the young are born or hatched helpless

Preformationism – the idea that organisms develop from miniature versions of themselves. It suggests that all organisms were created at the same time, and that succeeding generations grow from homunculi, or animalcules, that have existed since the beginning of creation

Prokaryote – an organism, such as bacteria, that lacks nuclei and other complex cell structures

Protogynous – hermaphrodites that are born female and at some point in their lifespan change sex to male. Protogynous animals include the wrasses and clownfish

Proventriculus – between crop and gizzard in birds

Proximal – the part of an organ or limb that is nearest from the attachment to the body

Pseudopod – ‘false foot’ projection of an amoeba that enables it to creep forward

Punnett square – a diagram that is used to predict an outcome of a particular cross or breeding experiment

Quadrat – a square measuring area used to sample living things in a given site

Quorum sensing – a system of stimulus and response correlated to population density. Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population

Radula – an anatomical structure that is used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon

Rostral – a body part located towards an animal’s mouth or nose

Section – a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section

Semelparous – species characterized by a single reproductive episode before death. An example of a semelparous organism is Pacific salmon, which lives for many years in the ocean before swimming to the freshwater stream of its birth, laying eggs, and dying

Sere – an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community

Sessile – (zoology) animals are those which are not able to move about, e.g. barnacles

Spermaceti – a wax that is most often found in the head cavities of the sperm whale. It is created in the spermaceti organ. Used in wax candles

Spermatophore – a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation

Spiracle – an opening on the surface of some animals that usually leads to respiratory systems

Stomach of cattle has four compartments. They are the rumen, reticulum, omasum, and abomasum, with the rumen being the largest compartment. The reticulum, the smallest compartment, is known as the ‘honeycomb’

Synecology – the study of relationships between communities and their environment

Syrinx – vocal cord of birds

Tapetum lucidum – a layer of tissue in the eye of many vertebrates. Lying immediately behind the retina it reflects visible light back through the retina and contributes to the superior night vision of some animals

Taxon – a group of (one or more) organisms, which a taxonomist adjudges to be a unit

Taxonomy – at higher ranks (family and above) a lower level may be denoted by adding the prefix infra, meaning lower, to the rank. For example infraorder (below suborder)

Tetrapod – four-limbed vertebrate

Thermogenesis – the process of heat production in organisms

Thorax – formed by the prothorax, mesothorax and metathorax, in an insect

Torsion – an anatomical event which takes place during the very early part of the life of snails and slugs. It is the rotation of the visceral mass, mantle, and shell 180˚ with respect to the head and foot of the gastropod

Transect – a straight line across the landscape area along which a study of distribution and abundance of species is made. Quadrats are placed at points on the transect

Tribe – a taxonomic rank between family and genus. It lies below ranks with names derived from family, such as subfamily. It is sometimes subdivided into subtribes. The standard ending for the name of a botanical tribe is ‘-eae’

Type specimen – the original specimen from which the description of a new species is made

Ventral – a body part located towards an animal’s chest or abdomen

Viviparous – animals that give birth to live young

Waggle dance – a term used in beekeeping and ethology for a particular figure-eight dance of the honey bee. Karl von Frisch was one of the first who translated the meaning of the waggle dance

Withers – ridge between shoulder blades of a horse

Zooid – a single animal that is part of a colonial animal

Zygodactyly – an arrangement of digits in birds, with two toes facing forward (digits 2 and 3) and two back (digits 1 and 4). This arrangement is most common in arboreal species, e.g. parrots and woodpeckers

Botany

Accessory fruit (sometimes called pseudocarp) – a fruit in which some of the flesh is derived not from the ovary but from some adjacent tissue exterior to the carpel. Examples of accessory tissue are the receptacle of the strawberry and pineapple

Actinomorphic – (‘star shaped’, ‘radial’), meaning that flowers can be divided into three or more identical sectors which are related to each other by rotation about the centre of the flower

Action spectrum – reaction of a plant to light. The efficiency with which electromagnetic radiation produces a photochemical reaction plotted as a function of the wavelength of the radiation

Adventitious – in botany, refers to structures that develop in an unusual place, and in medicine, it refers to conditions acquired after birth

Alternation of generations – used to describe the life cycle of plants. A multicellular gametophyte, which is haploid, alternates with a multicellular sporophyte, which is diploid

Angiosperm (Magnoliaphyte) – a plant whose ovules are enclosed in an ovary

Angiosperm Phylogeny Group – an informal international group of systematic botanists who came together to try to establish a consensus on the taxonomy of flowering plants (angiosperms) that would reflect new knowledge about plant relationships discovered through phylogenetic studies. As of 2010^[update], three incremental versions of a classification system have resulted from this collaboration (APG I, APG II, and APG III)

Aphyllous – plant without leaves

Apical meristem, or growing tip, is a completely undifferentiated meristematic tissue found in the buds and growing tips of roots in plants

Areoles – small light- to dark-colored bumps on cacti out of which grow clusters of spines

Autotroph – an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) from simple inorganic molecules using energy from light (by photosynthesis) or inorganic chemical reactions (chemosynthesis). They are the producers in a food chain, such as plants on land or algae in water. They are able to make their own food and can fix carbon

Auxins – a class of plant growth substance (often called phytohormone or plant hormone)

Immunogenicity is the ability of a particular substance, such as an antigen or epitope, to provoke an immune response in the body of a human or animal

Beta-carotene – a strongly-coloured red-orange pigment abundant in plants and fruits. The milk from a Guernsey cow has a golden colour due to an exceptionally high content of beta-carotene. Beta-carotene is the most important source of Vitamin A

Biological Nitrogen Fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by a pair of bacterial enzymes called nitrogenase

Bryology – study of mosses

Bundle-sheath cells are photosynthetic cells arranged into tightly packed sheaths around the veins of a leaf

Cambium – a tissue layer that provide undifferentiated cells for plant growth (a type of meristem)

Capitate – with knob-like head; of an inflorescence, with the flowers unstalked and aggregated into a dense cluster; of a stigma, like the head of a pin, e.g. sunflower

Carotenoids are organic pigments that are naturally occurring in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae. They are split into two classes, xanthophylls (which contain oxygen) and carotenes (which are purely hydrocarbons, and contain no oxygen)

Carpel – the outer, often visible part of the female reproductive organ of a flower. The parts of the carpel are: stigma, usually the terminal (end) portion that has no epidermis and is fitted to receive pollen (male gametes); style, a stalk connecting the stigma with the ovary below containing the transmitting tract, which facilitates the growth of the pollen tube and hence the movement of the male gamete to the ovule; and ovary containing the female reproductive cell or ovule

Cellulose – a carbohydrate that is insoluble in water and is the main component of cell walls in plants

As chlorophyll breaks down and disappears from leaves in autumn, red and orange carotenoids and yellow xanthophylls combine to create a paint-box of shades. The effect is further enhanced by sugars produced by the leaves reacting with phenols to create other pigments that range from purple-blue to bright scarlet

Chloroplasts – organelles found in plant cells and eukaryotic algae that conduct photosynthesis. Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant

Chitin is the main component of the cell walls of fungi. It is also a major component of the exoskeletons of arthropods, such as the crustaceans (e.g. crab, lobster, and shrimp), and the insects (e.g. ants, beetles, and butterflies), and of the beaks of cephalopods (e.g. squids, and octopus)

Chlorophyll A is the primary photosynthetic pigment

Clubroot is a common disease of cabbages, radishes, turnips and other plants belonging to the family Cruciferae (mustard family)

Corm – a fleshy, thickened, vertical, underground stem, usually having annual segments with a bud at the tip, thin external scale leaves, and roots at the base

Cruciferous – having flowers with four equal petals arranged crosswise

Cryptogam – a plant that reproduces by spores

Dehiscence – the opening of a plant structure in a pre-defined way at maturity in order for it to release its contents, and is common among fruits. Sometimes this involves the complete detachment of a part. Structures that open in this way are said to be dehiscent. Structures that do not open in this way are called indehiscent

Dicotyledon – a flowering plant with two embryonic seed leaves or cotyledons that usually appear at germination

Dioecious – plants or invertebrates having the male and female reproductive organs in separate individuals

Denitrification – a microbially facilitated process of dissimilatory nitrate reduction that may ultimately produce molecular nitrogen (N₂) through a series of intermediate gaseous nitrogen oxide products

Double fertilization – involves the joining of a female gametophyte with two male gametes (sperm). It begins when a pollen grain adheres to the stigma of the carpel

Endosperm – the tissue produced inside the seeds of most flowering plants around the time of fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. Wheat endosperm is ground into flour for bread, while barley endosperm is the main source for beer production

Epiphyte – plant that derives moisture and nutrients from the air and rain; usually grows on another plant but not parasitic on it

Eudicotyledons – a clade of flowering plants. The botanical terms were introduced in 1991 by evolutionary botanist James A. Doyle and paleobotanist Carol L. Hotton to emphasize the later evolutionary divergence of tricolpate dicots from earlier, less specialized, dicots. The other name for the eudicots is tricolpates, a name which refers to the grooved structure of the pollen. Members of the group have tricolpate pollen, or forms derived from it. This pollen have three or more pores set in furrows

Flavonoids are the most important plant pigments for flower coloration producing yellow or red/blue pigmentation in petals designed to attract pollinator animals

Floret – literally a small flower, but usually refers to the individual true flowers clustered within an inflorescence

Fruit – the ripened ovaries of flowering plants

Gametophyte – a haploid multicellular adult stage during the life cycle of land plants and algae. It produces haploid gametes. It is produced from mitotic cell division of spores, which are produced by meiosis in sporophytes. Gametophytes produce male or female gametes (or both), by mitosis

Gymnosperm – a plant, such as a conifer, whose seeds are not enclosed within an ovary

Herbaceous – a plant lacking a permanent woody stem

In addition to pigmentation, there may be a second major component to leaf colour, structural colour. Leaves may appear lighter in colour, i.e., gray, silver, white, blue, copper, or gold, so that the green is not easily observed. This modification of color is due primarily to structures formed on the leaf surface that increase reflectance

Meristem – the tissue in most plants consisting of undifferentiated cells, found in zones of the plant where growth can take place

Monocotyledon – any of various flowering plants, such as grasses, orchids, and lilies, having a single cotyledon in the seed

Monoecious – plants having both the male and female reproductive organs in the same individual

Mycorrhiza – a symbiotic association between a fungus and the roots of a vascular plant

Nastic – relates to the movement of a plant in response to a stimulus

Nictonasty – a diurnal, nastic movement (e.g. the opening of certain flowers in the day and their closing at night)

Nut – a general term for the large, dry, oily seeds or fruit of some plants

Ovule – the structure that gives rise to and contains the female reproductive cells in seed plants

Palynology – the study of living or fossil plant spores and pollen

Perianth – consists of the calyx (all sepals) and the corolla (all petals) of the flower

Pericarp – the part of a fruit formed from the wall of the ripened ovary

Phellem – botanical name for cork

Phloem – transports food round the plant

Photoperiodism – growth response of plants to varying lengths of daylight and darkness

Photosynthesis – begins when energy from light is absorbed by proteins called reaction centres that contain green chlorophyll pigments. In plants, these proteins are held inside chloroplasts, while in bacteria they are embedded in the plasma membrane

Phototaxis – a kind of taxis that occurs when a whole organism moves in response to the stimulus light

Phytoestrogens – plant-derived xenoestrogens functioning as the primary female sex hormone not generated within the endocrine system but consumed by eating phytoestrogenic plants

Pistil – made up of a carpel (if single) or carpels (if fused)

Plant hormones – (also known as phytohormones) are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'

Plastids are major organelles found in the cells of plants and algae, e.g. chloroplasts

Pneumatophores –specialized root structures that grow out from the water surface, e.g. in mangraves

Potometer – sometimes known as a transpirometer, is a device used for measuring the rate of water uptake of a leafy shoot

Procumbent – having stems that trial along the ground

Pteridology – study of ferns

Raceme – an unbranched, indeterminate type of inflorescence bearing pedicellate flowers (flowers having short floral stalks)

Raunkiaer system – used for categorizing plants using life-form categories, devised by Christen C. Raunkiaer

Receptacle – the thickened part of a stem from which the flower organs grow

Reniform – kidney-shaped leaves

Rhizoid – simple hair-like protuberances that extends from the lower epidermal cells of bryophytes and pteridophytes

Root nodules – occur on the roots of plants that associate with symbiotic nitrogen-fixing bacteria

Sap – a fluid transported in xylem cells or phloem sieve tube elements of a plant

Seed – a small embryonic plant enclosed in a covering called the seed coat

Sepal – collectively the sepals are called the calyx, the outermost whorl of parts that form a flower. Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom

Sessile – (botany) means ‘without a stalk’, as in flowers (pedicel) or leaves (petiole) that grow directly from the stem

Stomata – the breathing pores on the surface of a plant's leaves. Opening and closing of stomata is regulated by guard cells. Plants respond to high levels of atmospheric carbon dioxide by evolving high densities of stomata on their leaf surfaces

Stamen – the male organ of a flower. Each stamen generally has a stalk called the filament, and, on top of the filament, an anther. The anther is usually composed of four pollen sacs, called microsporangia. The stamens in a flower are collectively called the androecium

Spore – a small usually single-celled asexual reproductive body produced by many nonflowering plants and fungi and some bacteria

Taproot – plant root that grows vertically downward

Tepal – is usually applied when the parts of the perianth are difficult to distinguish, e.g. the petals and sepals share the same colour

Thigmotropism – a movement in which a plant moves or grows in response to touch or contact stimuli, e.g. tendrils coiling round objects. Also known as haptotropism

Thykaloid – suspended within the chloroplast stroma is the thylakoid system, a highly dynamic collection of membranous sacks called thylakoids where chlorophyll is found and the light reactions of photosynthesis happen. In most vascular plant chloroplasts, the thylakoids are arranged in stacks called grana

Transpiration – the process by which water absorbed by plants, usually through the roots, is evaporated into the atmosphere from the plant surface, principally from the leaves

Trichomes – fine outgrowths or appendages on plants, e.g. stings on nettles

Urticating bristles – i.e. irritating bristles, are one of the primary defence mechanisms used by numerous plants, some New World tarantulas, and various caterpillars. Urtica is Latin for ‘nettle’

Vacuole – organelle which is present in all plant cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution

Vernalization – the acquisition of a plant's ability to flower or germinate in the spring by exposure to the prolonged cold of winter

X – The multiplication sign ‘x’ is used to indicate that a plant is a hybrid, e.g. Saxifraga x urbium

Xylem – transports water round a plant

Zygomorphic – (‘yoke shaped’, ‘bilateral’) flowers can be divided by only a single plane into two mirror-image halves, e.g. orchids

Viruses

Bacteriophage – a virus that infects bacteria

Baltimore classification – developed by David Baltimore, is a virus classification system that groups viruses into families, depending on their type of genome (DNA, RNA, single-stranded, double-stranded, etc.) and their method of replication

Endogenous viral element (EVE) – a DNA sequence derived from a virus, and present within the germline of a non-viral organism. EVEs may be entire viral genomes (proviruses), or fragments of viral genomes

Lysogeny – or the lysogenic cycle, is one of two methods of viral reproduction (the lytic cycle is the other). Lysogeny is characterized by integration of the bacteriophage nucleic acid into the host bacterium's genome

Prion – a microscopic protein particle similar to a virus but lacking nucleic acid. Responsible for fatal brain diseases such as CJD

Retroviridae – a family of enveloped viruses that replicate in a host cell through the process of reverse transcription. A retrovirus is a single-stranded RNA virus that stores its nucleic acid in the form of an mRNA genome and targets a host cell as an obligate parasite. Once inside the host cell cytoplasm the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern

Viroid – a plant pathogen that consists of a short length of RNA

Virus – a complete virus particle, known as a virion, consists of nucleic acid surrounded by a protective coat of protein called a capsid. These are formed from identical protein subunits called capsomeres. All viruses have genes made from either DNA or RNA; all have a protein coat that protects these genes; and some have an envelope of fat that surrounds them when they are outside a cell. The vast majority of viruses have RNA genomes

Genetics

Acquired character – a change in a part of an animal’s body that occurs during its lifetime, as distinct from an inherited characteristic

Allele – any one of a number of viable DNA codings occupying a given locus (position) on a chromosome. Usually alleles are DNA sequences that code for a gene. One of the possible forms in which a gene can be expressed in an individual. Gene variant

Allele frequency or gene frequency is the proportion of a particular allele (variant of a gene) among all allele copies being considered

Aneuploidy – having extra or missing chromosomes

Autosome – a chromosome that is not a sex chromosome

Centrosome – an organelle that serves as the main microtubule organizing centre of the animal cell. Centrosomes are composed of two orthogonally arranged centrioles

Chiasma – the point where two homologous non-sister chromatids exchange genetic material during chromosomal crossover during meiosis

Chromatid – one of two identical strands of DNA making up a chromosome that are joined at their centromeres, for the process of nuclear division (mitosis or meiosis)

Chromatin – the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are 1) to package DNA into a smaller volume to fit in the cell, 2) to strengthen the DNA to allow mitosis, 3) to prevent DNA damage, and 4) to control gene expression and DNA replication

Dahlias are octaploid (eight sets of chromosomes)

Chimpanzees and gorillas have 48 chromosomes

Cisgenesis – (from ‘same’ and ‘beginning’) is one term for organisms that have been genetically engineered using a process in which genes are artificially transferred between organisms that could otherwise be conventionally bred. Unlike in transgenesis, genes are only transferred between closely related organisms

Codominance – one allele is not completely dominant over another, e.g. red and white flowers may produce pink offspring

Cytokinesis – the process in which the cytoplasm of a single eukaryotic cell is divided to form two daughter cells

Dihybrid cross – a cross between F₁ offspring (first-generation offspring) of two individuals that differ in two traits of particular interest

Diploid – having two of the basic sets of chromosomes in the nucleus. Most eukaryotes are diploid. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous

Dominant allele – produces a trait in an individual even when it is inherited from one parent only

Epigenome – consists of a record of the chemical changes to the DNA and histone proteins of an organism; these changes can be passed down to an organism's offspring

Epistasis – the phenomenon where the effects of one gene are modified by one or several other genes, which are sometimes called modifier genes

Fossil gene – a gene that is no longer used as it is not required, e.g. human sense of some smells

Founder effect – the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population

Gene – first isolated in 1969 by Beckwith

Danish botanist Wilhelm Johannsen coined the word ‘gene’ in 1909 to describe the fundamental physical and functional units of heredity

Humans share 98.4% of their genes with chimpanzees

William Bateson, a proponent of Mendel's work, coined the word ‘genetics’ in 1905

Genetic drift – change in the frequency of a gene variant (allele) in a population due to random sampling

Genetic linkage – a term which describes the tendency of certain loci or alleles to be inherited together. Genetic loci on the same chromosome are physically close to one another and tend to stay together during meiosis, and are thus genetically linked

Genome – the whole hereditary information of an organism that is encoded in the DNA. This includes both the genes and the non-coding sequences. The term was coined in 1920 by Hans Winkler, as a portmanteau of the words gene and chromosome

Genome – human genome is c. 3.2 billion base pairs and between 30,000 and 40,000 genes

DNA was first sequenced in 1977. The first free-living organism to have its genome completely sequenced was the bacterium Haemophilus influenzae, in 1995. In 1996 Saccharomyces cerevisiae (baker's yeast) was the first eukaryote genome sequence to be released

Mustard cress – first plant to have genome sequenced, in 2000

Nematode worm – first animal to have DNA sequenced, in 2003 by John Sulston

Genotype is the specific genetic makeup (the specific genome) of an individual, in the form of DNA. Together with the environmental variation that influences the individual, it codes for the phenotype of that individual

Haploid – a single set of chromosomes (half the full set of genetic material), present in the egg and sperm cells of animals and in the egg and pollen cells

Hardy–Weinberg principle – states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences

Histones – highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are the chief protein components of chromatin

Homeobox – a DNA sequence found within genes (a genetic switch) that are involved in the regulation of patterns of anatomical development (morphogenesis) in animals, fungi and plants. Discovered by Walter Gehring and his group

Homologous chromosomes – chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci. One homologous chromosome is inherited from the organism's mother; the other from the organism's father

Housekeeping genes – perform basic functions that are needed by every cell

Incomplete dominance – the snapdragon flower colour is either homozygous for red or white. When the red homozygous flower is paired with the white homozygous flower, the result yields a pink snapdragon flower. The pink snapdragon is the result of incomplete dominance

Karyotype – the characterization of the chromosomal complement of an individual or a species, including number, form, and size of the chromosomes

Lac operon – three adjacent linked genes which code for the enzymes that act sequentially in lactose utilization

Linkage map – a genetic map of a species or experimental population that shows the position of its known genes or genetic markers relative to each other in terms of recombination frequency, rather than as specific physical distance along each chromosome. Linkage mapping is critical for identifying the location of genes that cause genetic diseases

Lysenkoism – a campaign against genetics and geneticists which happened in the Soviet Union from the 1930s to the 1960s. Lysenko developed a theory of genetics which suggested that environment can alter the hereditary material. He pronounced the Mendelian theory of heredity to be wrong

Meiosis – the process that transforms one diploid cell into four haploid cells in order to redistribute the diploid's cell's genome. Forms the basis of sexual reproduction. Meiotic division occurs in two stages, dividing the cells once at each stage

Mendel’s laws – the Law of Segregation (The First Law) and the Law of Independent Assortment (The Second Law). The Law of Segregation states that every individual possesses a pair of alleles for any particular trait and that each parent passes a randomly selected copy (allele) of only one of these to its offspring. The Law of Independent Assortment states that separate genes for separate traits are passed independently of one another from parents to offspring

Mendel’s paper about inheritance in pea plants was published in 1866. He suggested that inside each pea plant were tiny units of inheritance, which he called ‘factors’

Missing heritability – the fact that individual genes cannot account for much of the heritability of diseases, behaviors, and other phenotype. A person's susceptibility to disease may depend more on the combined effect of all the genes in the background than on the disease genes in the foreground

Mitosis – the process by which a cell separates its duplicated genome into two identical halves. The four basic stages of mitosis are: prophase, metaphase, anaphase and telophase. The normal state of a cell is known as interphase

Monohybrid cross – a mating between individuals who have different alleles at one genetic locus of interest

Monosomy – a form of aneuploidy with the presence of only one chromosome (instead of the typical two in humans) from a pair

Mutations – changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus

Nucleoid – an irregularly-shaped region within the cell of a prokaryote that contains all or most of the genetic material. In contrast to the nucleus of a eukaryotic cell, it is not surrounded by a nuclear membrane

Oncogene – a gene that, when mutated or expressed at high levels, helps turn a normal cell into a tumour cell

Operon – a unit of genetic material that functions in a coordinated manner by means of an operator, a promoter, and one or more structural genes

Pharming – the use of genetic engineering to insert genes that code for useful pharmaceuticals into host animals or plants that would otherwise not express those genes

Phenotype – of an individual organism is either its total physical appearance and constitution or a specific manifestation of a trait, such as size, eye colour, or behaviour that varies between individuals

Ploidy – the number of homologous sets of chromosomes in a biological cell

Polyploid – cells and organisms containing more than two paired (homologous) sets of chromosomes

Population genetics – the study of the allele frequency distribution and change under the influence of the four evolutionary processes: natural selection, genetic drift, mutation and gene flow. Its primary founders were Wright, Haldane and Fisher

Recessive allele – produces a trait in an individual only when it is inherited from both parents

Recombination hotspots – small regions in the genome of sexually reproducing organisms that exhibit highly elevated rates of meiotic recombination

Spindle fibres – the structure that separates the chromosomes into the daughter cells during cell division

Synapsis – the pairing of two homologous chromosomes that occurs during meiosis

Telomere – a region of DNA at the end of a chromosome, which protects the end of the chromosome from deterioration

Transgenesis – the process of introducing an exogenous gene, called a transgene, into a living organism so that the organism will exhibit a new property and transmit that property to its offspring

Transposon – (transposable element) is a DNA sequence that can change its position within the genome, sometimes creating or reversing mutations. Barbara McClintock discovered transposition (‘jumping genes’) and used it to show how genes are responsible for turning physical characteristics on or off

X0 sex-determination system – a system that grasshoppers, crickets, cockroaches, and some other insects use to determine the sex of their offspring. In this system, there is only one sex chromosome, referred to as X. Males only have one X chromosome (X0), while females have two (XX). The zero signifies the lack of a second X. Maternal gametes always contain an X chromosome, so the sex of the animals' offspring is decided by the male

ZW sex-determination system is a system that determines the sex of offspring in birds, some fish and crustaceans, some insects (including butterflies and moths), and some reptiles, including komodo dragons. In the ZW system, the ovum determines the sex of the offspring. Males are the homogametic sex (ZZ), while females are the heterogametic sex (ZW). The Z chromosome is larger and has more genes, like the X chromosome in the XY system

Zygote – a diploid cell formed as a result of fusion of two haploid nuclei during sexual reproduction

Evolution

Adaptation – a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection

Adaptive radiation – a process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available. Four of the 14 finch species found on the Galapagos Archipelago are thought to have evolved by an adaptive radiation

Atavism – an evolutionary throwback, such as traits reappearing which had disappeared generations before

Coevolution – the change of a biological object triggered by the change of a related object, e.g. bumblebees and the flowers they pollinate

Convergent evolution – the acquisition of the same biological trait in unrelated lineages. The wing is a classic example of convergent evolution in action

Extirpation – local extinction of a species

Industrial melanism – originally, the vast majority of peppered moths (Biston betularia) had light colouration, which effectively camouflaged them against the light-coloured trees and lichens which they rested upon. However, because of widespread pollution during the Industrial Revolution, many of the lichens died out, and the trees that peppered moths rested on became blackened by soot, causing most of the light-coloured moths, or typica, to die off from predation. At the same time, the dark-coloured, or melanic, moths, carbonaria, flourished because of their ability to hide on the darkened trees. Since then, with improved environmental standards, light-coloured peppered moths have again become common

Lamarckism – the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring (also known as heritability of acquired characteristics or soft inheritance). It is named after the French biologist Jean-Baptiste Lamarck (1744 – 1829), who incorporated the action of soft inheritance into his evolutionary theories. After publication of Charles Darwin's theory of natural selection, the importance of individual efforts in the generation of adaptation was considerably diminished

Mimicry – occurs when a group of organisms, the mimics, have evolved to share common perceived characteristics with another group, the models. Types of mimicry: Batesian mimicry – a situation where a harmless species has evolved to imitate the warning signals of a harmful species directed at a common predator; Mullerian mimicry – two or more harmful species, that are not closely related and share one or more common predators, have come to mimic each other's warning signals

Phylogenetics – the study of evolutionary relationships among groups which are discovered through molecular sequencing data

Red Queen Hypothesis – taken from the Red Queen's race in Lewis Carroll's Through the Looking-Glass. The Red Queen said, "It takes all the running you can do, to keep in the same place”. The Red Queen Principle can be stated thus: ‘For an evolutionary system, continuing development is needed just in order to maintain its fitness relative to the systems it is co-evolving with’

Speciation – the evolutionary formation of new biological species, usually by the division of a single species into two or more genetically

Transmutation of species – a term used by Lamarck in 1809 for his theory that described the altering of one species into another, and the term is often used to describe 19th century evolutionary ideas that preceded Darwin's theory of natural selection

Biologists

Charlotte Auerbach discovered that mustard gas could cause mutations in fruit flies. This, and her later work, founded the science of mutagenesis

Between 1900 and 1910 William Bateson directed an informal school of genetics at Cambridge. His group consisted mostly of women associated with Newnham College, Cambridge. The women carried out a series of breeding experiments in various plant and animal species

Herbert Boyer is considered to be a pioneer in the field of recombinant DNA technology (gene splicing). In 1973, Boyer and his colleague Stanley Cohen demonstrated that restriction enzymes could be used as ‘scissors’ to cut DNA fragments of interest from one source, to be ligated into a similarly cut plasmid vector. Created synthetic human insulin in 1978

Henri Dutrochet has been given credit for discovering cell biology and cells in plants and the actual discovery of the process of osmosis

In 1927, Charles Elton published his now classic book Animal Ecology. This book outlines the important principles of ecological studies of animal behaviour and life history, such as food chains, the size of food items, the ecological niche and the concept of a pyramid of numbers as a method of representing the structure of an ecosystem in terms of feeding relationships

Jan Baptist Van Helmont (who coined the word ‘gas’) thought that mice came from wheat (spontaneous generation)

Johannes Miescher isolated various phosphate-rich chemicals, which he called nuclein (now nucleic acids), from the nuclei of white blood cells in 1869, paving the way for the identification of DNA as the carrier of inheritance. The significance of the discovery, first published in 1871, was not at first apparent

Following the rediscovery of Mendelian inheritance in 1900, Thomas Hunt Morgan's research moved to the study of mutation in the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University Morgan was able to demonstrate that genes are carried on chromosomes and are the mechanical basis of heredity

Oparin-Haldane Hypothesis – Aleksandr Oparin (in 1924), and John Haldane (in 1929), independently suggested that if the primitive atmosphere was reducing (as opposed to oxygen-rich), and if there was an appropriate supply of energy, such as lightning or ultraviolet light, then a wide range of organic compounds might be synthesized. Haldane coined the term 'prebiotic soup'

Miriam Rothschild was the first person to work out the flea's jumping mechanism

Glossary

Actinobiology – the study of effects of radiation upon living organisms

Adduction – a movement which brings a part of the anatomy closer to the middle sagittal plane of the body. It is opposed to abduction

Algae – any of numerous groups of chlorophyll-containing, mainly aquatic eukaryotic organisms ranging from microscopic single-celled forms to multicellular forms

Algor mortis – the reduction in body temperature following death

Ames test – a biological assay to assess the mutagenic potential of chemical compounds

Anabolic steroids – increase protein synthesis within cells, which results in the buildup of cellular tissue (anabolism), especially in muscles, e.g. nandrolone

Androgen – the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates

Anti-oncogene – a tumour suppressor gene that protects a cell from one step on the path to cancer. When this gene is mutated to cause a loss or reduction in its function, the cell can progress to cancer

Apoptosis – programmed cell death. Cells that realise there is something wrong commit suicide

Autophagy – a catabolic process involving the degradation of a cell's own components through the lysosomal machinery

Bioassay – an experiment designed to determine how much of a substance is present by measuring its biological effect, e.g. on the growth of an organism

BioBrick – standard biological parts are DNA sequences of defined structure and function; they share a common interface and are designed to be composed and incorporated into living cells such as E. coli to construct new biological systems. BioBrick parts represent an effort to introduce the engineering principles of abstraction and standardization into synthetic biology

Biogenesis – the formation of living organisms from their ancestors

Biohacker (biopunk) – a hobbyist who experiments with DNA and other aspects of genetics

Biological Oxygen Demand – (BOD) is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period

Catabolism – the metabolic breakdown of complex molecules into simpler ones, often resulting in a release of energy

Cell potency – a general term which describes a stem cell's ability to differentiate into different cell types. The more cell types a stem cell can differentiate into, the greater its potency

Cell theory – refers to the idea that cells are the basic unit of structure in every living thing. Development of this theory during the mid 17th century was made possible by advances in microscopy

Centrifuge – a device that rotates at various speeds about a fixed, central point. It can separate liquids from solids or liquids of different densities

Chaperone proteins – assist the non-covalent folding/unfolding and the assembly/disassembly of other macromolecular structures

Casein – protein in milk

Chymosin – (or rennin) is an aspartic acid protease enzyme found in rennet

Circadian rhythm – the rhythmic repetition of certain phenomena in living organisms at about the same time each day

Contact inhibition – normal somatic cells become growth inhibited when they encounter another cell

Crypsis – the ability of an organism to avoid observation or detection by other organisms

Dialysis – a process for removing waste and excess water from the blood

Electroreception – the biological ability to perceive natural electrical stimuli. It has been observed only in aquatic or amphibious animals

Endocytosis – an energy-using process by which cells absorb molecules (such as proteins) by engulfing them

Gamete – a cell that fuses with another cell during fertilization in organisms that reproduce sexually

Gravid – the condition of an animal when carrying eggs internally

Harmful algal bloom (HAB) is an algal bloom that causes negative impacts to other organisms

Heterogamy – union of dissimilar reproductive cells

Heterosis – also known as hybrid vigour or outbreeding enhancement, describes the increased strength of different characteristics in hybrids; the possibility to obtain a genetically superior individual by combining the virtues of its parents

High Density Lipoprotein – (HDL) takes cholesterol out of the bloodstream. Known as ‘good cholesterol’

Histology – the study of tissues

Homeostasis – the ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes

Hypertonic solution – one with a higher concentration of solutes outside the cell than inside the cell. When a cell is immersed into a hypertonic solution, the tendency is for water to flow out of the cell in order to balance the concentration of the solutes

Hypotonic solution – has a lower concentration of solutes outside the cell than inside the cell. In an attempt to balance the concentrations of solutes inside and outside the cell, water will rush into the cell, causing it to swell and possibly burst

Integumentary system – the organ system that protects the body from various kinds of damage, such as loss of water or abrasion from outside. The system comprises the skin and its appendages (including hair, scales, feathers, hooves, and nails)

Lactic acid – formed when milk goes sour

Low Density Lipoprotein – (LDL) delivers cholesterol to the body. Known as ‘bad cholesterol’

Melanism – an increased amount of black or nearly black pigmentation (as of skin, feathers, or hair) of an organism, resulting from the presence of melanin. It is the opposite of albinism, which occurs due to lack of melanin

Membrane potential – difference in electrical current between the inside and outside of a cell

Metabolism – the chemical processes occurring within a living cell or organism that are necessary for the maintenance of life

Metabolomics – the systematic study of the unique chemical fingerprints that specific cellular processes leave behind

Omega-9 fatty acids – can be used by the body as a substitute for omega-3’s or 6’s if these essential fats are not present. Omega-9’s are found in animal fats and vegetable oils, most notably olive oil

Osmosis – the movement of water across a semipermeable membrane from an area of high water potential (low solute concentration) to an area of low water potential (high solute concentration)

Phagocytosis – the cellular process of engulfing solid particles by the cell membrane to form an internal phagosome by phagocytes and protists. Monocytes and macrophages are phagocytes

Phenol red – a pH indicator that is frequently used in cell biology laboratories and home swimming pool test kits

Phycology – study of algae

Reverse osmosis – most commonly known for its use in drinking water purification from seawater, removing the salt and other substances from the water molecules

Saprobe – an organism that derives its nourishment from nonliving or decaying organic matter (saprotrophic nutrition). Refers to fungi and soil bacteria

Sequential hermaphroditism – occurs in many fish, gastropoda and plants. Sequential hermaphroditism occurs when the individual changes sex at some point in its life. They can change from a male to female (protandry),or from female to male (protogyny) or from female to hermaphrodite (protogynous hermaphroditism)

Serotype – or serovar refers to distinct variations within a species of bacteria or viruses or among immune cells of different individuals

Somatic cell – any cell of the body except sperm and egg cells

Sporocarp – also known as fruiting body or fruit body, is a multicellular fungal structure on which spore-producing structures, such as basidia or asci, are borne. The fruiting body is part of the sexual phase of a fungal life cycle, with the rest of the life cycle being characterized by vegetative mycelial growth and asexual spore production. The sporocarp of a a basidiomycete is known as a basidiocarp or basidiome, while the fruiting body of an ascomycete is known as an ascocarp

Sporophyte – the diploid multicellular stage in the life cycle of a plant or alga. It develops from the zygote produced when a haploid egg cell is fertilized by a haploid sperm and each cell therefore has a double set of chromosomes, one set from each parent

Synthia (Mycoplasma laboratorium) – the first synthetic cell. Produced by Craig Venter

Synthetic biology – a new area of biological research that combines science and engineering. The design and construction of new biological functions and systems not found in nature

Taxis – an innate behavioural response by an organism to a directional stimulus or gradient of stimulus intensity. A taxis differs from a tropism (turning response, often growth towards or away from a stimulus) in that the organism has motility and demonstrates guided movement towards or away from the stimulus source. It is sometimes distinguished from a kinesis, a non-directional change in activity in response to a stimulus that results in the migration toward or away from a stimulus

Teratology – concerned with the development of malformations or serious deviations from the normal type of organism

Water potential – the potential energy of water relative to pure free water. Useful in understanding water movement within plants, animals, and soil

Zymology – study of fermentation. Also known as zymurgy