ONLY bio definitions

• • Movement: an action by an organism or part of an organism causing a change of position or place
• • Respiration: the chemical reactions that break down nutrient molecules in living cells to release energy for metabolism
• • Sensitivity: the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
• • Growth: a permanent increase in size and dry mass by an increase in cell number or cell size or both
• • Reproduction: the processes that make more of the same kind of organism
• • Excretion: the removal of toxic materials, the waste products of metabolism and substances in excess of requirements from the body of organisms
• • Nutrition: the taking in of materials for energy, growth and development; plants require light, CO2, water and ions; animals need organic compounds, ions and usually need water
• All vertebrates have a backbone
• • Invertebrates do not possess a backbone
• Nucleus

  • Contains the DNA (genetic material) which controls the activities of the cell
• • Specialised cells are those which have developed certain characteristics in order to perform particular functions. These differences are controlled by genes in the nucleus
• inheritance: the transmission of genetic information from generation to generation
• genetic modification: changing the genetic material of an organism by removing, changing or inserting individual genes
• a sustainable resource as one which is produced as rapidly as it is removed from the environment so that it does not run out
• biodiversity is the number of different species that live in an area
• population is a group of organisms of one species, living in the same area, at the same time
• a community is all of the populations of different species in an ecosystem
• an ecosystem is a unit containing the community of organisms and their environment, interacting together
• food chain: showing the transfer of energy from one organism to the next, beginning with a producer
• food web:

  a network of interconnected food chains
• a producer is an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
• a consumer is an organism that gets its energy by feeding on other organisms. consumers may be classed as primary, secondary, tertiary and quaternary according to their position in a food chain
• a herbivore is an animal that gets its energy by eating plants
• a carnivore is an animal that gets its energy by eating other animals
• a decomposer is an organism that gets its energy from dead or waste organic material
• a trophic level is the position of an organism in a food chain, food web or ecological pyramid
• adaptation: the process, resulting from natural selection, by which populations become more suited to their environment over many generations
• natural selection:

  (a) genetic variation within populations

  (b) production of many offspring

  (c) struggle for survival, including competition for resources

  (d) a greater chance of reproduction by individuals that are better adapted to the environment than others

  (e) these individuals pass on their alleles to the next generation

  selective breeding:

  (a) selection by humans of individuals with desirable features

  (b) crossing these individuals to produce the next generation

  (c) selection of offspring showing the desirable features
• adaptive feature: an inherited feature that helps an organism to survive and reproduce in its environment
• variation: differences between individuals of the same species
• continuous variation results in a range of phenotypes between two extremes; examples include body length and body mass
• discontinuous variation results in a limited number of phenotypes with no intermediates; examples include ABO blood groups, seed shape in peas and seed colour in peas
• discontinuous variation is usually caused by genes only and continuous variation is caused by both genes and the environment
• mutation is a (genetic change) random change in the base sequence of DNA and is the way in which new alleles are formed. ionising radiation and some chemicals increase the rate of mutation.
• codominance as a situation in which both alleles in heterozygous organisms contribute to the phenotype
• sex-linked characteristic is a feature in which the gene responsible is located on a sex chromosome and that this makes the characteristic more common in one sex than in the other
• inheritance is the transmission of genetic information from generation to generation
• genotype is the genetic make-up of an organism and in terms of the alleles present
• phenotype is the observable features of an organism
• homozygous as having two identical alleles of a particular gene