Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account


change over time

geographic isolation

form of reproductive isolation in which two populations are separated by geographic barriers such as rivers, mountains, or bodies of water, leading to the formation of two separate subspecies


group of similar organisms that can breed and produce fertile offspring

sexual selection

when individuals select mates based on heritable traits


formation of a new species

directional selection

form of natural selection in which individuals at one end of a distribution curve has higher fitness than individuals in the middle or at the other end of the curve


the study of past and present distribution of organisms

analogous structure

body parts that share a common function, but not structure

behavioral isolation

from of reproductive isolation in which two populations develop differences in courtship rituals or other behavior that prevent them from breeding

artificial selection

selective breeding of plants and animals to promote the occurrence of desirable traits in offspring


heritable characteristic that increases an organism's ability to survive and reproduce in an environment

genetic equilibrium

situation in which allele frequencies in a population remain the same

bottleneck effect

change in allele frequencies as a result of the migration of small subgroup of a population

founder effect

a change in allele frequency following a dramatic reduction in the size of a population

Hardy Weinberg Principle

principle that states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change

stabilizing selection

form of natural selection in which individuals near the center of the distribution curve have higher fitness than individuals at either end of the curve

reproductive isolation

separation of a species or population so that they no longer interbreed and evolve into two separate species

homologous structures

structures that are similar in different species of common ancestry


preserved remains or traces of ancient organisms

polygenic trait

trait controlled by two or more genes

natural selection

process by which organisms that are most suited to their environment survive and reproduce most successfully, also called survival of the fittest

gene pool

all the genes, including all the different alleles for each gene, that are present in a population at any one time

temporal isolation

form of reproductive isolation in which two or more species reproduces at different times

single- gene trait

trait controlled by one gene that has two alleles

genetic drift

random change in allele frequency caused by a series of chance occurrences that cause an allele to become more of less common in a population

allele frequency

number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene


how well an organism can survive and reproduce in its environment

vestigial structure

structure that is inherited from ancestors but has lost or all of its original function

disruptive selection

form of natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals in the middle or at the other end of the curve.

molecular clock

method used by researchers that uses mutation rates in DNA to estimate the length of time that two species have been evolving independently
comparison of DNA sequences between species can show how many mutations occurred independently in each group

Charles Darwin

born feb. 12, 1809
went on HMS Beagle's five year voyage in 1831

3 distinctive patterns of biological diversity

1. species vary globally
2. species vary locally
3. species vary over time

Hutton and Lyell

geologists. said that Earth is older than we previously thought. said that processes that changed Earth in the past are the same processes we see in the present


had a false statement that organisms can pass acquired characteristics to their offspring. was first to suggest a link between an organism's environment and its body structure


scientist that stated that if populations grew unchecked, there wouldn't be enough living space and food for everyone

Alfred Russel Wallace

spent year observing and gathering data in Indonesia area and wrote a letter to Darwin. discovered "reproductive isolation" in the Malay Archipelago

descent with modification

living species are descended, with modification, from common ancestors.
according to this all species - living and extinct- are descended from ancient common ancestors

natural selection on single- gene traits

can lead to changes in allele frequencies which changes frequencies of phenotypes

natural selection on polygenic traits

can affect the distribution of phenotypes in 3 ways:
directional, stabilizing, disruptive

evolutionary fitness

the success in passing genes to the next generation

evolutionary adaptation

any genetically controlled trait that increases an individual's ability to pass along its alleles

sources of genetic variations

muatations, genetic recombination in sexual reproduction, lateral gene transfer

lateral gene transfer

passing of genes from one organism to another that is not its offspring

evolution in genetic terms

any change in the relative frequency of alleles in the gene pool of a population over time

what natural selection acts directly on

acts on phenotypes not genotypes

what genetic variation and evolution are studied in

they are studied in populations

The Grants' Investigation

documented that natural selection takes place frequently and sometimes rapidly.
showed that variation within a species increases the likelihood that the species can adapt and survive environmental change

5 conditions to maintain genetic equilibrium

must be random mating
population must be very large
no mutations
no immigration or emigration
no natural selection

Hox genes

determine which part of an embryo develops arms, legs, or wings. Groups of hox genes also control the size and shape of the those structures
small changes in this can cause activity during embryological development to produce large changes in adult animals

evidence of evolution

biogeography, fossils, anatomy and embryology, vestigial structures, genetics (universal code and homologous molecules)

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording