Chapter 3

Question 1

What was Darwin’s conclusion in On the Origin of Species b Means of Natural Selection?

Answer 1

Earth’s organisms were not independently created, but are instead descended with modification form a single common ancestor or a few

Question 2

What is the process that yields the pattern e call evolution?

Answer 2

Natural selection

Question 3

What was the final act that led to a greater acceptance of natural selection?

Answer 3

The rediscovery of Mendel’s ideas in 1900 and other three decades of work on population genetics

Question 4

Darwin’s postulates on natural selection:

Answer 4

1. The individuals within a population differ from one another
2. The differences are, at least in part, passed from parents to offspring
3. Some individuals are more successful at surviving and reproducing than others
4. The successful individuals are not merely lucky; instead, they succeed because of the variant traits they have inherited and will pass to their offspring

Question 5

If all of Darwin’s postulates hold, what happens?

Answer 5

The composition of the population inevitably changes from one generation to the next

Question 6

Darwinian fitness:

Answer 6

An individual’s ability to survive and reproduce

Question 7

Adaptation:

Answer 7

A trait that increases an organism’s fitness relative to individual’s lacking it

Question 8

Heritability:

Answer 8

The fraction of the variation in a population that is due to differences in genes

Question 9

Which of the following is a true statement regarding pre adaptations?

Answer 9

A trait that evolved for one function, but that coincidentally is also suited for a new, different function

Question 10

Which of the following statement is central to the idea of uniformitarianism?

Answer 10

Natural laws that are observable today also operated in the past. Geological change happens gradually for the most part

Question 11

Successful artificial selection, such as that practiced by plant and animal breeders to modify their crops and livestock, depends on which of the following?

Answer 11

Breeders must be able to selectively breed the individuals with the most desirable traits. Some individuals must have more desirable traits than others. When individuals with the most desirable traits are bred, their traits must be passed from parent to offspring.

Question 12

Which is the best definition of Darwinian fitness?

Answer 12

The ability of an individual to survive and reproduce in a certain environment, compared to other individuals

Question 13

Exaptation:

Answer 13

A trait that is used in a novel way. They represent coincidence. It enhances an individual’s fitness fortuitously. A trait that is elaborated into a completely new structure by selection related to its new function.

Question 14

Secondary adaptations

Answer 14

Additional modifications that arise during exaptation.

Question 15

Blending inheritance:

Answer 15

Favorable variants would merge into existing traits and be lost. Biologist thought inheritance worked like pigments in paint. Instead, alleles are passed on intact to offspring, thus making inheritance particulate (not blending).

Question 16

What are angiosperms?

Answer 16

Monocots + Dicots

Question 17

Testing postulate 3: Do individuals vary in their success at surviving and reproducing?

Answer 17

In every natural population studied, more offspring are produced each generation that survive to breed.

Question 18

Testing postulate 4: Are survival and reproduction nonrandom?

Answer 18

Individuals who survive and go on to reproduce, or who reproduce the most, are those with certain variations.
In the case of the Galapagos finches, seeds ranged from small and soft to large and hard, as the soft and small seeds were the first to be eaten, only large and hard seeds were left after the drought, large birds with deep, narrow beaks were more successful at cracking the seeds left and therefore more successful at surviving and reproducing.

Question 19

Testing Darwin’s prediction: Did the population evolve?

Answer 19

Because of the drought, the finch population evolved. Selection occurs within generations; evolution occurs between generations

Question 20

The nature of natural selection

Answer 20

Natural selection acts on individuals, but its consequences occur in populations
Natural selection acts on phenotypes, but evolution consists of changes in allele frequencies.
Natural selection is not forward looking; evolving populations always lag at least a generation behind changes in the environment.
Although selection acts on existing traits, new traits can evolve via mutations and genetic recombination.
Natural selection does not lead to perfection.
It is nonrandom, but it is not progressive.

Question 21

Natural selection is nonrandom, but is not progressive

Answer 21

The automatic sorting among variant phenotypes and genotypes to increase survival and reproduction of some variants over other is non random. However, it is not progressive in the sense of moving toward a predetermined goal.
There is no such thing as a higher or lower plant or animal.

Question 22

Selection acts on individuals, not for the good of the species

Answer 22

Individuals do not do things for the good of their species. They behave in a way that maximizes their genetic contribution to future generations.

Question 23

Modern synthesis of Darwin’s postulates

Answer 23

1. Individuals vary as a result of mutation creating new alleles, and segregation and independent assortment shuffling alleles into new combinations.
2. Individuals pass their alleles on to their offspring intact.
3. In every generation, some individuals are more successful at surviving and reproducing than others.
4. The individuals most successful at surviving and reproducing are those with the alleles and allelic combinations that best adapt them to their environment.

Question 24

The argument from intelligent design/creationism

Answer 24

Contends that adaptation- traits that increase the fitness of individuals that possess them- must result from the actions of a conscious entity

Question 25

What would Lamarck and Darwin have agreed on?

a. One generation can pass on its traits to the next.
b. Individual animals and plants can adapt to their environment.
c. Life was driven from simplicity to complexity.
d. Both a and b
e. Both b and c

Answer 25

a. One generation can pass on its traits to the next.

Question 26

Who is Linnaeus

Answer 26

Father of taxonomy

Question 27

Who is Cuvier

Answer 27

Pope of bones

Question 28

Who paved the way for popular acceptance and transmutability?

Answer 28

Buffon and Erasmus Darwin

Question 29

Who made significant contributions to understanding process of evolution?

Answer 29

Lamarck and Lyell

Question 30

Diversity results from

Answer 30

Decent with modification

Question 31

Homology

Answer 31

A trait shared by two organisms as a result of inheritance from a common ancestor

Question 32

Lamarck’s proposed postulates

Answer 32

1. Use or disuse causes changes in organismal structure during its lifetime
2. The structural changes that occur in an organism’s lifetime are inherited by its offspring

Question 33

Natural selection can only act on traits that:

a. are acquired by parents during their lifetime
b. will be useful in the future
c. increase longevity
d. are heritable
e. are influenced by the environment

Answer 33

D. Are heritable

Question 34

The flippers of a seal and turtles could be considered:

a. convergent, because they did not evolve from common ancestor with flippers.
b. analogous, because they both function in swimming.
c. Homologous, because they contain the same series of bones inherited from their common tetrapod ancestor.
d. adaptations, because they were produced by natural selection under selective pressure for swimming.
e. all of the above

Answer 34

E. All of the above

Question 35

Why does postulate 3 have to be true in natural selection? (individuals vary in their success at surviving or reproducing

Answer 35

For stable population, only 2 can survive to reproduce (on average) per mating pair.

Question 36

Which postulate is not necessarily always true?

Answer 36

Postulate 4 (Survival and/or reproduction is nonrandom), but when it is true, natural selection is the only possible outcome.

Question 37

What were the contributions of Gregor Mendel to understanding inheritance?

Answer 37

Law of segregation: each gamete receives one of two alleles for each gene and each parent contributes one randomly selected to offspring.- No blending!
Law of independent assortment: each trait inherited independently from other (we now know this is only true if genes are on separate chromosomes).

Question 38

Modern synthesis:

Answer 38

Gradual evolution results from small genetic changes that are acted upon by natural selection.
The origin of species and higher taxa, or macroevolution, can be explained in terms of natural selection acting on individuals, or microevolution.