Natural Selection

Question 1

Evolution

Answer 1

the process of biological change in populations over time
-makes descendants different from ancestors

Question 2

Two types of Evolution

Answer 2

Microevolution:
-on a small scale
-affects one population
Macroevolution:
-on a large scale
-affects species across populations

Question 3

Charles Darwin

Answer 3

-english naturalist
-went to Galapagos islands
-Saw: Different species have diff. traits for their environments
-theory of Natural Selection
-“Survival of the fittest”

Question 4

Natural Selection

Answer 4

organisms with the best traits live longer and reproduce more, changing the population over time

Question 5

Principals of Natural Selection: Overproduction of Offspring

Answer 5

too many offspring and limited resources, causes competition over resources

Question 6

Principals of Natural Selection: Variation

Answer 6

different physical traits in organisms
Sources: Random Mutation (ultimate sources), genetic recombination (meiosis), migration

Question 7

Principals of Natural Selection: Adaptation

Answer 7

features that allow an organism to better survive
-beneficial traits become more common (changing gene pool)

Question 8

Principals of Natural Selection: Descent with Modification

Answer 8

-change in gene frequency over time (new phenotypes)
-Always starts with: “Over time…”

Question 9

3 Modes of Selection

Answer 9

Directional: favors one extreme
Disruptive: favors two extremes
Stabilizing: favors heterozygous

Question 10

Allele Frequencies

Answer 10

p: frequency of dom allele
q: frequency of rec allele
p+q=1

Question 11

Hardy-Weinberg Equilibrium

Answer 11

p2: genotype freq of homo dom
q2: genotype freq of homo rec
2pq: genotype freq of hetero
p2+2pq+q2=1
-Only used when no changes in allele frequencies

Question 12

Mechanisms of Microevolution: Mutations

Answer 12

-change in DNA sequence
-creates new geno + phenotypes
-changes allele freq
-increases variation
-can be harmful, neutral, or beneficial

Question 13

Mechanisms of Microevolution: Natural Selection

Answer 13

organisms more fit for their environment will live longer + reproduce more
-beneficial traits become more common

Question 14

Mechanisms of Microevolution: Genetic Drift

Answer 14

random change in allele freq. in a population over time
-rare alleles decrease in freq
-change is more apparent in smaller populations

Question 15

Mechanisms of Microevolution: Gene Flow

Answer 15

movement of genes in and out of a population
-during migration

Question 16

Mechanisms of Microevolution: Sexual Selection

Answer 16

traits that help an organism reproduce but does not help their fitness
-cannot reproduce w/out
-(non-random mating)

Question 17

Genetic Equilibrium (Hardy Weinberg Equilibrium)

Answer 17

when there’s no changes in the allele freq. in a population over time
Conditions:
-population is large
-random mating
-No migration
-No mutation
-No natural selection