Theories
What theory describes the change in a species over time?
evolution
An inherited trait that improves an organism's ability to survive and reproduce in a particular environment
adaptation
Describes the formation of new species as a result of evolution by natural selection
speciation
Structures that are similar, but that have different forms and/or functions
homologous structures
the likelihood an individual will survive and reproduce
fitness
selects for traits that make individuals better at securing mates
sexual selection
This theory states that individuals best adapted to an environment are more likely to survive and reproduce.
natural selection
Favors beneficial traits within a population
selecting agent
The inability of a species to breed successfully with related species
reproductive isolation
Remnants of structures that were functional in an ancestor, but that are now generally reduced in size and serve little or no function
vestigial structures
Describes evolution as a slow, continuous process over a long period of time
gradualism
favors behavior that benefits a population or species over individuals
group selection
This scientist believed that evolution occurred due to the inheritance of acquired traits
Lamarck
Differences among members of a species
variations
When mating is prevented by physical barriers
geographical isolation
Structures that are similar in function, but not in form
analogous structures
A pattern of evolution characterized by relatively rapid change, followed by long periods of little change
punctuated equilibrium
random changes in allele frequencies
genetic drift
Who observed that processes that operate in the past continue to operate now?
Lyell and Hutton
Genetic shuffling (crossing over, independent assortment, random fertilization) AND mutation
When mating is prevented by differences in timing
temporal isolation
If organisms share many similarities in anatomy, embryology, and biochemistry, what does this evidence suggest?
They share a common ancestor
Describes all of the alleles in all individuals that make up a population
gene pool
when individuals (and their alleles) move into or out of a population
gene flow
Who stated that limiting factors kept human population growth in check?
Malthus
What factors are necessary for evolution to occur?
genetic variation, overproduction, limited resources, environmental change
What factors must be maintained for populations to be in genetic equilibrium?
no selection, no mutation, no migration, large population size, random mating
In layers of sedimentary rock, in what layer would you find the oldest fossils?
the bottom layer
drastic reduction in population size that reduces genetic diversity
bottleneck effect
What conditions cause evolution to occur more quickly in organisms?
short reproductive cycle, produce many offspring, reproduce sexually