Chapter 7 (Part 2)

Question 1

Darwin’s finches

Answer 1

a closely related group of distinct species
→ Birds are similar to each other except for the shape of their bills
→ Genetic differences (in the timing and amount of two genes) account for the physical differences in the beaks
→ Birds with larger beaks make more of a protein called BMP4 (bone morphogenic protein 4) and calmodulin.

Question 2

Proportion of a specific beak shape

Answer 2

changed over time depending on the type of food available in different ecological niches.

Question 3

Rate of evolutionary change can occur in two ways…

Answer 3

Gradualism and Punctuated equilibrium

Question 4

Gradualism

Answer 4

evolutionary change that occurs extremely slowly over a long period of time

Question 5

Punctuated equilibrium

Answer 5

evolutionary change where species experience long periods of little or no evolutionary change (stasis) interrupted by bursts of significant
changes.

Question 6

three main types of evidence that support an existing species came from a common ancestor.

Answer 6

1. Fossils
2. The anatomical record
3. The molecular record

Question 7

soft tissues are (Likely/Unlikely) to be fossilized?

Answer 7

Unlikely

Question 8

most fossils are skeletons but they can also be…

Answer 8

feathers, scales, hooves, horns, teeth, and shells. Or…they can be the impression of a structure

Question 9

Fossilization is rare and conditions must be

Answer 9

perfect

Question 10

Fossils give a sequential picture of evolution for some species, but this is rare due t

Answer 10

the scarcity of fossils

Question 11

Similarities among primate skulls suggest that we evolved from…

Answer 11

a common ancestor

Question 12

Homologous structures

Answer 12

anatomical structures that share similar structure or origin, indicating possible descent from a common ancestor

Question 13

There are similarities in the macromolecules of species

Answer 13

mainly protein and DNA sequences

Question 14

The Earth is about __________ years old

Answer 14

4.5 billion

Question 15

Oceans formed _________ years ago

Answer 15

3.8 billion

Question 16

Prokaryotes first appeared __________ years ago

Answer 16

3.5 billion

Question 17

Eukaryotes (protists) – _________ years ago

Answer 17

1.5 billion

Question 18

Multicellular organisms – __________ years ago

Answer 18

1 billion

Question 19

Fish – ___________ years ago

Answer 19

500 million

Question 20

Amphibians – __________ years ago

Answer 20

350 million

Question 21

Insects – __________ years ago

Answer 21

300 million

Question 22

Dinosaurs – __________ years ago

Answer 22

250–65 million

Question 23

Mammals – _________ years ago

Answer 23

200 million

Question 24

Primates – __________ years ago

Answer 24

65 million

Question 25

Hominids – _________ years ago

Answer 25

2 million

Question 26

Homo sapiens – __________ years ago

Answer 26

200 000

Question 27

who studied the frequencies of genes in a gene pool

Answer 27

Hardy and Weinberg

Question 28

We can use population data to look at frequencies of…

Answer 28

phenotypes, genotypes, and alleles.

Question 29

Hardy-Weinberg equilibrium

Answer 29

When the proportions of allele frequencies and genotypes remain constant from generation to generation.
→ Therefore, the population is not evolving

Question 30

We can use phenotype frequencies to calculate the…

Answer 30

frequency of the genotypes and alleles in a population

Question 31

all combinations of genotypes possible in the population add up to

Answer 31

1

Question 32

Allele Frequencies

Answer 32

p + q = 1

Question 33

Genotype Frequencies

Answer 33

p2 + 2pq + q2 = 1

Question 34

Hardy-Weinberg equilibrium occurs only if…

Answer 34

1. the population is very large
2. mating is random
3. there are no mutations
4. there is no input of any new alleles
5. there is no natural selection (no selection pressure on that specific trait)

Question 35

The following factors can alter the proportions of genotypes enough to produce significant deviations from Hardy-Weinberg predictions

Answer 35

1. Selection
2. Mutation
3. Non-random mating
4. Migration
5. Genetic drift

Question 36

Mutation

Answer 36

is a change in DNA nucleotide sequence

Question 37

However, no matter how rare, mutation is the…

Answer 37

ultimate long-term source of variation in a population

Question 38

Migration

Answer 38

is the movement of individuals between populations.

Question 39

The effects of migration are based on two factors…

Answer 39

• the number of migrants in the population
• the difference in allele frequencies between the migrants and the original population

Question 40

Founder effect

Answer 40

• a special example of the effects of migration on the genetic diversity of a population
• occurs when a small group of migrants (not genetically representative of the population from which they came) establish in a new area`

Question 41

Genetic drift

Answer 41

the change in frequency of an existing gene variant in the population due to random chance

Question 42

genetic drift can cause

Answer 42

gene variants to disappear completely and thereby reduce genetic variation; and cause rare alleles to become more frequent

Question 43

The bottleneck effect

Answer 43

an extreme example of genetic drift that happens when the size of a population is severely reduced