Busy. Please wait.
Log in with Clever

show password
Forgot Password?

Don't have an account?  Sign up 
Sign up using Clever

Username is available taken
show password

Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
Your email address is only used to allow you to reset your password. See our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Didn't know it?
click below
Knew it?
click below
Don't Know
Remaining cards (0)
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

AP Bio Chapter 20/21

AP Bio Chapter 20/21: Phylogeny & Evolution of Populations

Phylogeny The evolutionary history of a species or group of related species.
Phylogenetic tree A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms.
Shared derived characters An evolutionary novelty that is unique to a particular clade (represented by a speciation event that occurs at a node).
Maximum parsimony A principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts.
horizontal gene transfer The transfer of genes from one genome to another through mechanisms such as transposable elements
population A group of individuals of the same species that live in the same area and interbreed
Hardy-Weinberg equilibrium The state of a population in which frequencies of alleles and genotypes remain constant from generation to generation
genetic drift A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. Effects of genetic drift are most pronounced in small populations.
founder effect Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflection of that of the original population.
bottleneck effect Genetic drift that occurs when the size of a population is reduced
gene flow The transfer of alleles from one population to another
relative fitness The contribution an individual makes to the gene pool of the next generation
sexual selection A process in which individuals with certain inherited characteristics are more likely than other individuals of the same sex to obtain mates.
Directional Selection Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.
Disruptive selection Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes.
Stabilizing Selection Natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes.
Created by: Hajra Maqsoos
Popular Biology sets




Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!
"Know" box contains:
Time elapsed:
restart all cards