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Allele - Alternate forms of a gene

Allopatric Speciation - Speciation that results when populations are physically separated in some way

Bias - Influence in a particular direction

Biodiversity - The number and variety of different organisms found in a particular area

Biodiversity Hotspot - Area which is particularly rich in different species

Bioindicator - Species that is particularly sensitive to change and so can be used to indicate problems in

an area which might lead to loss of biodiversity

Bioplastic - Plastic (polymer) made from monomers which come from a sustainable biological source

Captive Breeding Programme - Breeding individuals from an endangered species in zoos and parks to

save species from extinction

Capture/Recapture Technique - Method of estimating the population of a particular species in an area

which involves capturing individuals, marking them and releasing them and then capturing some of

them again

Carbon Neutral - No net release of carbon compounds into the atmosphere

Directional Stimulus - A change from one phenotype to another which is more advantageous under the

circumstances

Discontinuous Growth - Growth which takes place in a series of steps

Discontinuous Variation - Variation shown by features which are either present or not

Diversifying Selection - A form of natural selection which results in increased genetic diversity of a

population

Dominant - Allele which is expressed in the phenotype whether the individual is homozygous or

heterozygous

Ecological Isolation - Breeding isolation when two populations inhabit the same region but develop

Preferences for different parts of the habitat

Ecological Niche - The role of an organism within an ecological community

Ecological Species - Definition of species based on the ecological niche occupied by the organisms

Ecology - The study of the relationships between living organisms and their environment

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Ecosystem - Environment including all the living organisms interacting, the cycling of nutrients and the

physical and chemical environment in which the organisms are living

Endangered - Facing a very high risk of extinction in the wild

Endemic - A species which is unique to an area

Endemism - Species which only occur in a very specific small area such as an island, they are unique to

the area

Epistasis - When one gene in a polygenic trait alters or affects the expression of another gene

Extinction - The permanent loss of all members of a species

Founder Effect - Process by which any unusual alleles become relatively common in a population if only

a small number of individuals set up a population and one of the founder member has the unusual allele

Gene Flow - The movement of genes by the interbreeding of individuals in different populations

Gene Linkage - Genes that are inherited together in a linked unit of a chromosome

Gene Pool - All the different versions of genes (alleles) found in a population

Gene Probe - Technique for identifying active genes in a cell

Genetic Diversity - Variety of genes and alleles within a population

Genetic Engineering - Artificially changing the genetic material of an organism

Genetic Modification - Copying healthy genes and inserting them into the DNA of other organisms

Genotype - The genetic make-up of an organism

Genus - Group of similar species

Geographical Isolation - A physical barrier, e.g. a river or a mountain range, that separates individuals

and prevents breeding

Habitat - Place where an organism lives

Haploid - Cell containing a single set of chromosomes (half the full chromosome number (n))

Heterozygote - Individual with different alleles for the same gene

Heterozygote Advantage (Or Hybrid Vigour) - When the heterozygous state for a particular gene gives

advantages to the individual

Heterozygous - Having different alleles for the same gene

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Homologous Chromosome - One of a matching pair of chromosomes

Homologous Pair - Matching pairs of chromosomes

Homozygote - An individual with both alleles for a gene the same

Homozygous - Having both alleles for a gene the same

Human Genome Project - Massive international research programme that mapped the entire human

genome

Independent Assortment - The random distribution of chromosomes from parents into offspring

Indicator Species - Species which can be used to monitor pollution levels, food levels, etc

Induced Fit Hypothesis - Modified version of the lock-and-key hypothesis of enzyme action that

proposes a flexible shape for the active site which is modified once the substrate molecule is bound toform an active complex

Inflammatory Response - The response of the body to damaged tissue which involves swelling and

increased blood flow bringing white blood cells to the area

Isotonic - A solution with the same osmotic concentration as the cell contents

Karyotype - Image showing the chromosomes arranged into homologous pairs

Keystone Species - A species which has a major effect on its environment. A large number of other

species depend on a keystone species for their survival

Law Of Independent Assortment - Law of genetics, originally proposed by Gregor Mendel, which states

that different traits are inherited independently of each other

Law Of Segregation - Law of genetics, originally proposed by Gregor Mendel, ehcih states that one allele

for each trait is inherited from each parent and each pair of alleles is segregated (separated) when the

gametes are formed

Lifestyle - The way someone lives their life

Lock-And-Key Hypothesis - Model of enzyme action based on the idea of an active site which fits specific

reactants

Locus - Position of a gene on a chromosome

Longitudinal Study - Studies which follow the same group of individuals over a long period of time

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Mechanical Isolation - Reproductive isolation caused by anatomical changes in an animal or plant as a

result of mutation which make reproduction impossible

Metadata Analysis - Looking at a large number of studies and putting the data together

Microhabitat - Small area of a larger habitat

Molecular Phylogeny - Analysis of different chemicals and genes in different organisms to identify

interrelationships

Monoculture - An area containing only one type of genetically very similar plants

Monohybrid Cross - Genetic cross that considers just one gene

Morphology - Outer and inner appearance of an organism

Mortality - The ratio of the total number of deaths compared with the whole population, often

expressed as number of deaths per thousand people per year

Multifactorial Disease - Disease that is the result of many factors, some genetic and some

environmental, all interacting

Multipotent - Limited degree of pluripotency seen in somatic stem cells

Natural Selection - Process by which the organism best suited to a particular environment are most

likely to survive and pass on their advantageous genetic characteristics to their offspring

Oedema - Accumulation of fluid in a tissue

Oncogene - Gene that causes the production of uncontrolled amounts of protein which stimulate the

cell cycle and in turn cause uncontrolled cell replication

Organ - Group of tissues grouped into a structure to carry out a particular function

Organ System - Group of organs working together to carry out a particular function

Parthenogenesis - Reproduction in which an ovum or ovule develops and forms a new organism without

fusing with a male gamete

Phase 1 Trial - Trail in which a new drug is given to a small number of healthy volunteers

Phase 2 Trial - Trial in which a new drug is given to a small group of volunteer patients affected by the

condition the drug is designed to treat

Phase 3 Trial - Trial in which a new drug is used with a large group (5000+) of patients affected by the

condition the drug is designed to treat

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Physiological Adaptation - Adaptations of the biochemistry or physiology of an organism to the

environment in which it lives

Plasmodesmata - Sites of intercellular exchanges through cytoplasmic bridges between plant cells

Pluripotent - Cells with the potential to form most of the cell types needed in an organism

Polygenic Inheritance - Characteristics which are inherited through the interaction of several different

genes

Population - Group of organisms of the same species, living and breeding together in a particular niche

in a habitat

Primary Cell Wall - Flexible plant cell walls with cellulose microfibrils oriented in same direction

Primary Structure (Proteins) - The arrangement of amino acids in the polypeptide chains

Prokaryote - Single-celled organism which has no nuclear membrane and the genetic material is notorganised into chromosomes

Prosthetic Group - A non-protein group attached to a protein molecule

Proto-Oncogene - Gene which codes for proteins which stimulate the cell cycle

Quadrat - Apparatus used to identify an area for sampling

Quantitative Sampling - Counting the number of organisms within a measured are

Quaternary Structure (Proteins) - The 3D arrangement of more than one polypeptide chain in a molecule

Recessive - Allele which is only expressed in the phenotype when the individual is homozygous for the

allele

Reliable - Results which can be replicated by different people and on different occasions

Risk Factor - A factor that the probability of an event happening

Sample - Take measurements from a number of randomly selected areas

Sampling Error - Error which creeps into genetic investigations due to problems such as death of

offspring, inefficient sampling and chance

Seasonal Isolation - When the timing of reproductive fertility varies in different parts of a population,

making reproduction between the two groups impossible

Secondary Cell Wall - Inflexible, rigid plant cell wall built up as cellulose microfibrils are laid densely at

different angles to each other

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Secondary Structure (Proteins) - The repeating pattern in the structure of the peptide chains, e.g. alpha

helix

Sectioning - Making thin slices of tissue to prepare a microscope slide

Selection Pressure - Changes in an environment that mean that certain characteristics will give an

organism an advantage

Semiconservative Replication - Replication of DNA where the two strands unzip and new nucleotides

align alongside each strand

Sexual Selection - Selection for features that give reproductive success

Somatic Stem Cell - Adult cells with a limited ability to form other types of cells

Species - Group of closely related organisms that are all potentially capable of interbreeding to produce

fertile offspring

Species Richness - Measure of the number of species in a given area

Sticky Ends - The end of a cut DNA helix, with one strand left slightly longer than the other

Suspension - A solid mixed with a liquid in which the particles will separate out if the mixture is not

constantly moved or stirred

Sympatric Speciation - Speciation that takes place in spite of the fact that two populations remain

physically close to each other

Tensile Strength - Strength to resist pulling forces

Tertiary Structure (Proteins) - The 3D folding of the secondary structure

Totipotent - Cell with the potential to form all known cell types within an organism

Transgenic - Organisms which have genes from another organism engineered into their DNA

Translation - Process by which the genetic code is converted into new protein molecules directed by

RNA

True-Breeding - When two individuals are crossed, all of the offspring show the same phenotype

Valid - An investigation that is properly designed to answer the questions which are being asked

Vector - Means of carrying new gene into host DNA during genetic modification

Whole-Chromosome Mutation - Mutation resulting in loss or duplication of whole chromosomes