chp 17

Compare the phenotypes of polygenic traits to the phenotypes for single-gene traits.

SGT-controlled by a single gene PT-trait controlled by two or more genes

What can disruptive selection lead to?

Speciation

What can directional selection lead to?

Evolution

Define population. B) Are members of the same population members of the same species?

B.yes Pop-members of the same species the live in different areas

Draw a graph for the typical graph of distribution of polygenic traits. B) What is the graph called?

Bell shaped curve

What happened to the birds beaks during the dry season?

Bigger beaks

What does the hox gene control?

Body plans and embryos

____________________________ can be define as a ________________________ in allele frequencies.

Evolution, change

What is the founder effect?

Change in allele frequencies as a result of the migration of a small group of a population

Define and draw the curves for stabilizing selection, directional selection, and disruptive selection. Also know example of each type of selection.

Directional Selection- Form of natural selection when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the end of the curve One extremes Stabilizing Selection- Form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve No extreme Disruptive Selection-Natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve Both extremes

What is the Hardy-Weinberg Principle?

Five conditions are required to maintain genetics equilibrium 1.large Pop. 2.no mutations 3.random mating 4.no movement in/out population 5.no natural selection

What is genetic drift? B) What conditions need to happen for genetic drift to occur

GD-random change in allele frequencies that occurs in small populations Occurs in small populations

What is the first step that occurred in the speciation of the Galapagos finches?

Geographic isolation

Due to a mutation, a new fur color (orange) occurred in a population of rabbits. How will we know how this color affects the fitness of the rabbits?

If the orange rabbit survive to the next generation then it hasn't

What are the three sources of genetic variation?

Mutation, genetic variation during sexual reproduction, lateral gene transfer

What does natural selection act on?

Phenotype

What is reproduction isolation? B) Name and define the three types of reproductive isolation.

RI-condition in which a reproductive barrier keeps two species from interbreeding Behavioral Isolation- type of reproductive isolation in which two organisms have different mating rituals that prevent them from interbreeding Geographical Isolation-type of reproductive isolation in which two different species live in different habitats Temporal Isolation-form of reproductive isolation in which two populations reproduce at different times

What factor is necessary for the formation of a new species?

Reproductive isolation

Define species

a group of organisms so similar to one another that they can breed and produce fertile offspring

What is meant by the term genetic equilibrium?

allele frequencies remain constant.

What were the two testable assumptions that the Grants studied?

beak size changed as a result of changes in food supply Galápagos finches could have evolved from a common ancestor.

Define gene pool.

combined genetic information of all the members of a particular population