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Evolution

Terms in this set (51)

adaptation
a developed characteristic that enhances an organism's survival in its natural environment
adaptive radiation
a process where a lineage of organisms rapidly diversifies into many different forms and taxa with different adaptations; it can be triggered by many factors, such as changes to available resources, or other new challenges or opportunities; this is a type of divergent evolution
analogous structures
features of organisms that have the same function but not the same structure
biogeography
the study of the distribution of living things over a geographical area through geologic time
common ancestor
a species from which other species have evolved
convergent evolution
a process whereby unrelated organisms evolve similar adaptations in response to their environments
divergent evolution
when related species evolve new traits over time, away from the common ancestor, to give rise to new species
evolution
the process of gradual change in the gene pool of a population of organisms that results in new species
homologous structures
features of organisms that have the same general structure but different functions
speciation
the evolution of one or more new species from an ancestral species
vestigial structures
structures found in organisms that have lost most, if not all, of their original function in the course of evolution; in ancestral organisms the structures served a purpose, but in their descendants the structures become atrophied or rudimentary
adaptive evolution
changes in populations of organisms that make that population better adapted to its environment over time
allopatric speciation
speciation that occurs due to physical or geographic isolation
artificial selection
the breeding of plants and animals to produce desirable traits in successive generations; also known as selective breeding
biological fitness
the capacity of an individual to survive and pass on viable offspring
bottleneck effect
when a catastrophic event or a period of adverse conditions drastically reduces the size of a population
founder effect
a type of gene flow that occurs when a few individuals that have become isolated from a larger population do not carry all the alleles that were present in the original population
gene flow
the transfer of alleles that results from emigration and immigration of individuals between populations
gene pool
the range of genes and all their alleles present in a population
genetic drift
a change in the gene pool of a population as a result of chance; usually occurs in small populations
hybrid
offspring from parents from two different species; some hybrids are also fertile and can produce further offspring
inheritable
capable of being passed on to the next generation
isolating mechanism
a mechanism that prevents organisms from mating or producing viable offspring
mutation
a gene or chromosome that has undergone a change relative to the original gene or chromosome; it may also refer to the process of generating such changes
natural selection
the process where individuals with certain inheritable traits survive and reproduce more successfully than other individuals, leading to evolutionary change in the population
population
a group of individuals of the same species that live in the same area interbreed, producing fertile offspring
selection pressures
factors that influence the survival of an individual within a population
sympatric speciation
speciation that occurs without physical or geographic isolation
variable traits
traits that vary in the population due to differences in alleles carried by different individuals
biodiversity
the number and range of species that exist on Earth or in an ecosystem
cross-breeding
selective breeding by combining in the offspring a desirable feature of one individual with a different desirable feature of another individual
embryology
the study of the embryos of different species
generation
the time between the birth of an individual and when they produce their offspring
inbreeding
selective breeding between two closely related individuals
selection agent
an environmental factor that acts on a population during natural selection
sexual selection
a special case of natural selection, in which the environmental factor is the selection of a mate
acquired trait
A feature that is gained during an individual's lifetime
behavioural adaptation
A behaviour or action that helps an organism survive
competition
The struggle between organisms for resources, such as food or mates
genetic trait
A feature that can be passed down by genes to the next generation
inheritance
The passing down of traits via genes from one generation to the next
physiological adaptation
An internal bodily process that helps an organism survive
structural adaptation
A physical feature of the body that helps an organism survive
species
A group of similar organisms that can breed to produce fertile offspring
trait
A feature of an organism
ecological isolation
when two species that could interbreed do not because the species live in different areas
temporal isolation
when species that could interbreed do not because the different species breed at different times
behavioural isolation
when species that could interbreed do not because they perform different mating rituals to attract a mate
mechanical isolation
when species that could interbreed do not because the structure of their genitalia prevents them from mating
chemical isolation
when different species interbreed but do not produce viable offspring because of chemical barriers during fertilisation, pregnancy, or post-birth
geographical isolation
when physical barriers exist that keep two species that could interbreed from mating
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