chapter 23

Question 1

macroevolution

Answer 1

refers to evolutionary changed that occur at or above the species level. Its about the broad pattern

ex. think about the evolution of tetrapods from fish that’s macroevolution involves a major change in body plan.

Question 2

monomorphic

Answer 2

if all individuals in population are homozygous for an allele

Question 3

polymorphic

Answer 3

2 or more alleles for a gene . It can refer to a species with different forms of individuals (like a jaguar’s light or dark fur

Question 4

allelic frequencies remain constant if

Answer 4

• no mutation
• no migration
• no mate selection
• no genetic drift
• no natural selection

Question 5

h-w is disrupted by

Answer 5

• mutation ( new alleles)
• mate selection ( shuffling of allelic combinations)
• migration / gene flow
• genetic drift
• natural selection

Question 6

mutation

Answer 6

• original source of all new alleles
• usually harmful = deleterious
• slow if it is the only source of variation

Question 7

mate selection

Answer 7

• changes genotype frequencies but not allelic frequencies
• assortive mating - likes mate with likes, promotes interbreeding, more homozygotes
• dissassortive mating - rare in nature; more homozygotes

Question 8

migration ( gene flow)

Answer 8

• alleles exchanged between populations
• immigration- into. emigration- out of
• loss or gain of alleles
• not usually adaptive
• high amounts keep populations similar

Question 9

genetic drift

Answer 9

random change in allele frequency between generations
-reduces genetic variation
- small populations more susceptible to
- two causes of genetic drift
- founder effect and bottleneck effect

Question 10

founder effect

Answer 10

few individuals start a population different allele frequency than parent population

Question 11

bottleneck effect

Answer 11

• population reduced to small numbers

Question 12

natural selection

Answer 12

differential survival of phenotypes
- differential survival of genotyped
- only processes producing adaptive changes

Question 13

directional selection

Answer 13

shifts the overall makeup of the population by favouring variants of one extreme

Question 14

diversifying or disruptive selection

Answer 14

• favours variants of opposite extreme

Question 15

stabilizing selection

Answer 15

• culls extreme variants from the population

Question 16

not all evolution is

Answer 16

adaptive

Question 17

role of population size in genetic drift

Answer 17

has a greater impact on smaller populations, in small populations random events can significantly alter allele frequencies from one generation to the next

Question 18

fitness

Answer 18

an organisms ability to survive and reproduce in a particular environment

Question 19

mutations…

Answer 19

• the effect of mutations is very slow if natural selection doesn’t come into play
• are the original source of all new alleles in a species

Question 20

during an organisms lifetime which is most likely to help the organism respond properly to changes in its environment

Answer 20

change in gene expression

Question 21

which of the following is most likely to produce a butterfly species in the wild whose members have one. of two strikingly different colour patterns?

Answer 21

disruptive selection

Question 22

new alleles can arise by

Answer 22

mutation

Question 23

Mutations can be caused by factors such as e

Answer 23

Mutations can be caused by factors such as errors in DNA replication, exposure to UV light and other high-energy forms of radiation, and exposure to certain chemicals (see Concept 17.5).

Question 24

We can characterize a population’s genetic makeup by describing its

Answer 24

gene pool

Question 25

conditions for hardy Weinberg

Answer 25

no mutations - the gene pool is modified if mutations occur random mating - If individuals mate within a subset of the population, such as near neighbours or close relatives (inbreeding), random mixing of gametes does not occur and genotype frequencies change. no natural selection - Allele frequencies change when individuals with different genotypes show consistent differences in their survival or reproductive success.

Question 26

Chance events can also cause allele frequencies to fluctuate unpredictably from one generation to the next, especially in small populations

Answer 26

genetic drift

Question 27

When a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool differs from the source population; this is called the

Answer 27

founder effect

Question 28

The founder effect might occur,

Answer 28

for example, when a few members of a population are blown by a storm to a new island.

Question 29

genetic drift is significant in

Answer 29

small populations

Question 30

Genetic drift can cause allele frequencies to change at random.

Answer 30

Because of genetic drift, an allele may increase in frequency one year, then decrease the next; the change from year to year is not predictable

Question 31

A community is comprised of only one species.

Answer 31

false

Question 32

Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence?

Answer 32

genetic drift

Question 33

The latin word for "species" means:

Answer 33

appearance or type

Question 34

You are shown caterpillars of the moth Nemoria arizonaria. The caterpillars belong to the same species, but some of the caterpillars that were collected from oak flowers resemble oak flowers, while caterpillars collected from oak twigs resemble oak twigs. What is the most plausible explanation for the phenotypic variation?

Answer 34

The phenotypic variation appears to be influenced by the environment/diet.

Question 35

Which of the following statements is/are true about mutations:

Answer 35

the effect of mutations in a population is very slow if natural selection does not come into play are the original source of all new alleles in a species

Question 36

Which of the following is most likely to produce a butterfly species in the wild whose members have one of two strikingly different colour patterns?

Answer 36

disruptive selection

Question 37

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing

Answer 37

gene flow

Question 38

During an individual organism's lifetime, which of these is most likely to help the organism respond properly to changes in its environment?

Answer 38

change in gene expression