Chapter 12- Forces Of Evolutionary Change

Question 1

Evolution

Answer 1

“Descent with modification”

Organisms come from a common ancestor and adapt to their environment

Occurs when allele frequencies change from one generation to the next

Question 2

Levels of organization

Answer 2

Organism—>Population—>Community—>Ecosystem

Question 3

Population

Answer 3

A group of interbreeding organisms of the same species

Question 4

Gene pool

Answer 4

Entire collection of genes and alleles

Differ from population to population

Question 5

Lamark

Answer 5

Believed organisms become adapted to their environment during their lifetime and pass these adaptations to their offspring

Question 6

Charles Darwin

Answer 6

Evolution through natural selection

His work with finches in the Galápagos Islands distinguishes 14 different types with varying beak lengths but all other traits similar

Question 7

Artificial Selection

Answer 7

Humans choose desired features, allows only those that best express qualities to reproduce

Question 8

Natural Selection

Answer 8

Environment determines which individuals will survive and reproduce

Fittest individual possesses the best adaptations that increase chance of survival

Question 9

3 step process in which the environment chooses the fittest individual

Answer 9

1. Members of a population have qualities that can be passed down genetically
2. Organisms produce too many offspring for the amount of resources available in the environment
3. Competition for resources ensues and Organisms that are better adapted to the environment survive and reproduce, usually passing down the advantageous traits
4. Over time a larger proportion of the population have those advantageous traits

Question 10

Genotype determines phenotype

Answer 10

Organisms do not adapt based on need

Variation within a population will lead to new genotypes which lead to new, better adapted traits (phenotypes)

Question 11

3 Ways natural selection can shape a population

Answer 11

Directional

Disruptive

Stabilizing

Question 12

Directional

Answer 12

One phenotype is favored over another

Question 13

Disruptive

Answer 13

Extreme phenotypes are favored over an intermediate

Question 14

Stabilizing

Answer 14

Intermediate are favored over extremes

Question 15

Genetic Drift

Answer 15

Random chance changes in allele frequencies

More pronounced effect in smaller pops

Can lead to complete loss or fixation of certain alleles in a pop

Question 16

Founder Effect

Answer 16

Small group of individuals leave main pop and start a new colony

Gene frequencies change based on those possessed by the “founders”

Question 17

Population Bottleneck

Answer 17

Pop is greatly reduced in a small amt of time

Gene frequencies change according to those possessed by the survivors

Question 18

Gene Flow

Answer 18

Exchange of genes btw pops of the same species

Immigration/emigration