Chapter 14

Question 1

Who first explained natural selection as a mechanism of evolution in his writings?
Hint: C _ _ _ _ _ s D _ _ _ _ n.

Answer 1

Charles Darwin.

Question 2

What is natural selection?

Answer 2

Individuals with beneficial traits are more likely to survive and pass these traits onto offspring.

Question 3

What are adaptive phenotypes?

Answer 3

They are traits that are favorable in the environment.

Question 4

True or false: favorable characteristics are universal.

Answer 4

False, favorable characteristics are usually suited to a particular environment.

Question 5

What observations led Darwin to believe that species evolve rather than remain fixed? Hint:

1) F _ _ _ _ _ s resemble living organisms.
2) G _ _ _ _ _ _ _ _ _ _ l P _ _ _ _ _ _ s suggested that lineages change as organisms move to new habitats.
3) I _ _ _ _ _ s have diverse animal and plants that are related yet different from their mainland sources.

Answer 5

Fossils, Geographical Patterns, Islands.

Question 6

What is descent with modification? Hint: think of finches with varying beaks to accommodate different food sources.

Answer 6

Organisms evolve from a common ancestor but develop different adaptations based on needs.

Question 7

Evidence of evolution:

1) F _ _ _ _ l R _ _ _ _ _ s show that living organisms resemble once living organisms.
2) E _ _ _ _ _ s develop similarly.

Answer 7

Fossil Records, Embryos

Question 8

What is a homologous structure? List an example. Hint: what do humans and bats have in common?

Answer 8

A structure derived from the same body part present in an ancestor. Humans and bats have similar bones in their arms, indicating they evolved from a common ancestor.

Question 9

What is an analogous structure? List an example. Hint: how are birds and bats similar despite not being related?

Answer 9

They are similar-looking structures in unrelated lineages. Bats and birds have wings but are not related.

Question 10

What is convergent evolution? Hint: why do birds and bats have wings despite not being related?

Answer 10

Two species can develop similar looking structures- despite not being related- if is an advantage in their environment.

Question 11

What conditions must be present for the allele frequency of a gene to never change over generations?

1) Large P _ _ _ _ _ _ _ _ n
2) Random M _ _ _ _ g
3) No M _ _ _ _ _ _ n
4) No M _ _ _ _ _ _ _ n
5) No N _ _ _ _ _ l S _ _ _ _ _ _ _ n

Answer 11

Large Population, Random Mating, no Mutation, no Migration, no Natural Selection.

Question 12

What happens when a population reaches Hardy Weinberg equilibrium? Hint: its genotype frequencies don’t c _ _ _ _ e over generations.

Answer 12

Change.

Question 13

Mutation is r _ _e, but is the ultimate source of genetic variation. Mutation could change allele frequency.

Answer 13

Rare

Question 14

Mutation is r _ _e, but is the ultimate source of genetic variation. Mutation could change allele frequency.

Answer 14

Rare

Question 15

True or false: mutation could be adaptive (increases the frequency of good alleles) or deleterious (decreases the frequency of good alleles).

Answer 15

True.

Question 16

True or false: migration DOESN’T increase and decrease frequency of good alleles

Answer 16

False, it could increase or decrease the frequency of good alleles.

Question 17

What is genetic drift?

Answer 17

Refers to a change of allele frequencies in a SMALL population from generation to generation solely because of randomness in the chance for reproduction.

Question 18

What is founder’s effect?

Answer 18

A few individuals migrate and become the founders of a new, isolated population away from their place of origin.

Question 19

True or false: genetic drift merely increases the frequency of good alleles.

Answer 19

False, it could increase or decrease the frequency of good alleles.

Question 20

True or false: Nonrandom mating can change genotype frequencies without changing allele frequencies.

Answer 20

True.

Question 21

Natural selection does NOT increase the frequency of good alleles over generations.

Answer 21

False, those with good alleles are more likely to survive and pass on traits.

Question 22

True or false: an allele is considered good or bad relative to its environment.

Answer 22

True.

Question 23

What is disruptive selection?

Answer 23

Two extremes in an array of phenotypes become more common in a population.

Question 24

What is directional selection?

Answer 24

Eliminates one extreme from an array of phenotypes.

Question 25

What is stabilizing selection?

Answer 25

Both extremes from an array of phenotypes are eliminated.

Question 26

What is speciation?

Answer 26

A process of forming new species from preexisting species.

Question 27

What is a biological species?

Answer 27

Groups of naturally interbreeding populations that can produce fertile offspring. (Hence why a tiger + lion offspring is not considered one. They would not naturally breed in the wild).

Question 28

There are 2 types of reproductive isolating mechanisms:
Prezygotic isolating mechanisms.
Postzygotic isolating mechanisms.
What does each one mean?

Answer 28

1) Prezygotic prevents the formation of a zygote.

2) Postzygotic prevents proper functioning of the zygote once formed.

Question 29

Who is Alfred Wallace and why was his discovery significant?

Answer 29

He proposed that evolution occurs by natural selection.