| Term | Definition |
|---|
| genetic drift | Chance changes in allele frequency |
| species | a group of organisms so similar to one another that they can breed and produce fertile offspring |
| population | all the organisms of a given species that live together in the same area at a particular point in time |
| niche | full range of physical and biological conditions in which an organsim lives and the way in which the organism uses those conditions |
| allele frequency | The relative proportion of a specific allele within a population |
| mutation | A sudden, relatively random, permanent change in the DNA of the organism, only source of new alleles, sometimes induced by mutagens. |
| mutagen | A factor in the environment that induces mutations by damaging DNA |
| allele | varying form of a gene |
| gene | A recipe for a protein that is coded onto a small section of a chromosome |
| chromosome | 42 in every human cell, found in the nucleus, contains genes |
| genotype | What combination of alleles an individual has for a trait (AA, Aa, aa) |
| phenotype | What visible traits show up in an individual due to their genotype |
| DNA | deoxyribonucleic acid, a chemical molecule, a huge polymer. The monomer of it is a nucleotide |
| test cross | A test to prove the genotype of an individual that shows the dominant phenotype |
| heterozygous | Genotype of both a dominant and recessive allele |
| dominant allele | Will show up in an individual's phenotype even if only one is present |
| recessive allele | Will only show up in an individual's phenotype if there is two, ie no dominant |
| mitosis | cell division that creates two daughter autosome cells identical to the origional mother cell, allows growth, repair and asexual reproduction |
| meiosis | cell division where four gametes are created, each different, for sexual reproduction |
| gamete | sex cell |
| autosome | normal body cell |
| 3:1 | monohybrid phenotype ratio |
| 9:3:3:1 | F2 Mendelian ratio in dihybrid crosses |
| female | In plants, the ovule is (male/female): |
| male | In plants, the pollen is (male/female): |
| independant assortment | Homologous lining up randomly at equator, causing variation in gametes |
| crossing over | genes unlinked and make new combinations |
| 4 | there are _ sources of variation in meiosis |
| overproduction | More offspring are produced than survive to maturity |
| variation exists | In every population traits occur in a variety of phenotypes which origionate from differences in genotype |
| natural selection | survival of the fittest, life is a struggle for limited resources |
| survive, obtain food and reproduce | to be successful an organism must be able to: |
| abiotic | These factors are non-living, eg wind, sun, tide, etc |
| adaptation | Inherited features that improve the organism's chances of surviving and reproducing, can be structural, behavioural, physiological |
| age structure | Per centage of population in each of the three age classes, pre-reproductives, reproductives, and post-reproductives |
| biotic | These factors are living, eg predators, prey, competitors, etc |
| carnivore | eats only meat |
| community | All the interacting populations in a given location at a particular point of time |
| competition | Organisms competing for the same resources, for example food or territory |
| consumer | Does not produce its own food, must eat other organisms to obtain energy |
| decomposer | organisms in an ecosystem that break down organic material (dead organisms, their waste, etc.) |
| density | number of individuals per unit area |
| distribution | How the individuals are spread throughout the area, random, clumped or uniform |
| ecosystem | The community and the physical environment |
| habitat | All the biotic and abiotic factors influencing organisms in an area |
| herbivore | Eats only plant material, does not produce its own food |
| interspecific | Between two or more species |
| intraspecific | Within one species |
| limiting factor | Liebig's Law of the Minimum - there will always be one key factor that limits the distribution/survival of an organism when present in unfavourable levels |
| microclimate | climate within a small area that differs significantly from the climate of the surrounding area |
| mortality | death rate |
| mutualism | a relationship between organisms in which both species benefit |
| natality | birth rate |
| omnivore | eats both plant and animal material |
| parasitism | Predation but the host is not killed |
| producer | makes its own food using energy from the sun |
| quadrat | a square frame used in sampling |
| scavenger | eats dead animal material |
| stratification | vertical layers caused by organisms themselves, common with plants in forests |
| succession | changes in species distribution over time |
| survivorship | the chance of staying alive |
| tolerance | An organism can only occupy a particular habitat if all factors fall within its zone of ______ |
| transect | A line along which one reads and records the object of study (elevation, animal/insect life, plants) |
| trophic level | Feeding level along the food web/chain, eg plants are in the first level, herbivores in the second, carnivores that eat herbivores in the third |
| primary consumer | herbivores are this sort of consumer |
| secondary consumer | carnivores that eat herbivores are this sort of consumer |
| zonation | prominent horizontal banding of organisms that live in a particular habitat |
| kite diagram | portrays zonation distribution, obtained by taking quadrat samples along a transect line across a community |
| flows | energy: |
| cycle | nutrients: |
| biodiversity | the diversity of plant and animal life in a particular habitat (or in the world as a whole) |
| biome | an ecosystem covering a large area, for example the ocean |
| biosphere | the portion of the earth within which life exists |
| gradient | a change in an abiotic factor over time or space |
| energy | When 2 organisms have the same needs/preferences they are said to be in competition. Nature tends to act to reduce competition because it wastes: |
| carrying capacity | A balance between the reproductive potential of a species and the environmental resistance of the habitat |
| 10 | __% of energy is passed from one trophic level to the next |
| commensalism | one species benefits, the other is not affected |
| antibiosis | one species is harmed, the other is unaffected |
| gene pool | all the alleles of all the individuals that make up a population |
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