Ch. 15 Flashcards
Natural selection
A mechanism for change in populations
Mimicry
A structural adaptation that allows one species to resemble another species
Camouflage
An adaptation that allows a species to blend in with their surroundings
Homologous structure
Structural figures with common evolutionary origins
Analogous structures
The Cody parts of an organism that do not have a common evolutionary origin but are similar in function
Vestigial structure
A body structure that no longer serves its purpose but was useful for its ancestors
Embryo
Earliest stage of growth and development of both plants and animals
Gene pool
All of the alleles of a genes population being put together
Alleles frequency
The percentage of any specific allele in the gene pool
Genetic equilibrium
A population in which the frequency of alleles remains the same over generations
Genetic drift
The alteration of alleles frequencies by chance events
Stabilizing selection
Natural selection that favors average individuals in a population
Directional selection
Occurs when natural selection favors one of the extreme variations of a trait
Disruptive selection
Individuals with either extreme of a traits variation are selected
Speciation
The evolution of new species
Geographic isolation
Whenever a physical barrier divides a population
Reproductive isolation
Formally interbreeding organisms can no longer mate and produce offspring
Polyploid
An individual species with multiple of the normal set of chromosomes
Gradualism
A species ordinate through a gradual change of adaptations
Punctuated equilibrium
Specification occurs relatively quickly in rapid bursts with long periods of genetic equilibrium in between
Adaptive radiation
When an ancestral species evolves into a array of species to fit a number of diverse habitats
Divergent evolution
The pattern of evolution in which a species that once were similar to an ancestral species diverge, or become increasingly distinct
Convergent evolution
Distantly related organisms evolve similar traits
Artificial selection
Breeding organisms with specific traits in order to produce offspring with identical traits
