Unit 2 Post Class Assignment questions

Question 1

In a given population, a few individuals may, by random chance, leave behind more descendants than other individuals. Thus, the genes of the next generation will have a higher proportion of the alleles of the “lucky” individuals. Which concept does this example represent?

Answer 1

genetic drift

Question 2

Natural selection can only act on traits that:

Answer 2

are heritable.

Question 3

If evolution has occurred:

Answer 3

the allele frequencies in a population have changed.

Question 4

Which statement is the best description of evolution as currently understood by modern biologists?

Answer 4

Evolution is influenced by the differential survival and reproduction of phenotypes.

Question 5

A population is:

Answer 5

a group of individuals of the same species that live in the same general location and have the potential to interbreed.

Question 6

Which statement describes an important difference between natural selection and genetic drift?

Answer 6

Natural selection involves differential reproductive success in the struggle for existence in an environment, whereas genetic drift does not.

Question 7

Gene flow means most nearly the same as:

Answer 7

migration.

Question 8

Which statement about mutations is false?

Answer 8

Mutations are always passed on to offspring.

Question 9

___________ can result from many processes, including ___________ and __________.

Answer 9

Evolution; mutation; immigration

Question 10

The migration of reproductive individuals between populations results in a movement of alleles called:

Answer 10

gene flow.

Question 11

What wavelengths of light are absorbed by melanin?

Answer 11

ultraviolet

Question 12

What gene in humans is involved in melanin production?

Answer 12

MC1R

Question 13

What essential nutrient is broken down by UV light?

Answer 13

folate

Question 14

What evolutionary mechanism is most responsible for the variation in human skin color?

Answer 14

natural selection

Question 15

What essential nutrient is produced in our skin from UVB light?

Answer 15

vitamin D

Question 16

What is melanin?

Answer 16

a pigment in human skin

Question 17

Which of these is least likely to be an adaptation of an organism to its environment?

Answer 17

Cave fish have evolved degenerated eyes because they have no use for vision in dark, underwater caves.

Question 18

While traveling around the world on the HMS Beagle, Charles Darwin made which of the following observations?

Answer 18

Island species of finch closely resembled mainland finches.

Question 19

Darwin’s observations while traveling on the Beagle helped him develop which theory?

Answer 19

Species might change over time.

Question 20

Which statement best describes the difference between natural and artificial selection?

Answer 20

Natural selection can act without the input of humans; artificial selection requires some human input.

Question 21

“Scientists can never observe evolution in action.” This statement is:

Answer 21

false. Multiple replicated, controlled laboratory experiments and long-term studies of natural populations have enabled scientists to observe and measure evolution as it occurs.

Question 22

Natural selection means most nearly the same as:

Answer 22

differential reproductive success.

Question 23

According to Darwin’s theories and observations on “the struggle for existence,” organisms better suited to an environment have a greater probability of surviving and will also:

Answer 23

leave more offspring.

Question 24

The best measure of an organism’s fitness is:

Answer 24

the number of fertile offspring it produces.

Question 25

What is the difference between artificial selection and natural selection?

Answer 25

Artificial selection requires human intervention, whereas natural selection does not require human intervention.

Question 26

Which statement about Charles Darwin is false?

Answer 26

He influenced Malthus's ideas about the limits of population growth.

Question 27

How did bats coevolve/adapt in response to moths gaining the ability to hear/jam their ultrasonic clicks?

Answer 27

They moved the frequency and intensity of their echolocation cries away from the peak sensitivity of moth ears.

Question 28

What benefit do corals gain from their mutualism with zooxanthellae?

Answer 28

Energy from the photosynthetic Zooxanthellae.

Question 29

What is an example of Mullerian mimicry?

Answer 29

Monarch and Viceroy butterflies

Question 30

What is different about coevolutionary interactions and adaptations compared to other types of evolution?

Answer 30

They are reciprocal, when one organism adapts the other adapts in response.

Question 31

Which organismal interaction is NOT coevolutionary?

Answer 31

Commensalism

Question 32

What type of mimicry involves a non-harmful/toxic organism mimicking a harmful/toxic organism?

Answer 32

Batesian

Question 33

If DNA replication occurs by unwinding and rebuilding, then:

Answer 33

the two resulting DNA molecules each contain one original strand and one new strand.

Question 34

Errors sometimes occur when DNA duplicates itself. Why might that be a good thing?

Answer 34

New alleles are produced, making it possible for the population to evolve.

Question 35

All of the following are cells that undergo mitosis, except:

Answer 35

sperm cells.

Question 36

A human brain cell contains 46 chromosomes. It divides by mitosis. How many chromosomes will be in each daughter cell?

Answer 36

46

Question 37

What is the purpose of mitosis?

Answer 37

to make genetically identical cells for growth and replacement of dead cells

Question 38

Which of the following places the events of mitosis into the correct order?

Answer 38

Chromosomes condense, chromosomes line up in the middle of the cell, sister chromatids separate, and the cell divides into two.

Question 39

Sister chromatids are held together:

Answer 39

at the centromere.

Question 40

The function of the spindle is to:

Answer 40

move chromosomes

Question 41

Which of the following is the direct product of DNA replication?

Answer 41

two sister chromatids

Question 42

In humans, somatic cells have 46 chromosomes. Sperm and egg cells have:

Answer 42

23 chromosomes.

Question 43

Whether it is eggs or sperm being produced through meiosis, under normal circumstances, each gamete ends up with:

Answer 43

exactly one copy of each chromosome.

Question 44

Crossing over means the same as:

Answer 44

the process by which pieces of homologous chromosomes are exchanged.

Question 45

Chromosomes on which crossing over (recombination) takes place:

Answer 45

have a mixture of maternal and paternal chromosomes.

Question 46

Which statement about homologous chromosomes is false?

Answer 46

One of the two homologous chromosomes is produced by the cell during the DNA replication.

Question 47

Which process is necessary to prevent the doubling of genome size during sexual reproduction?

Answer 47

meiosis

Question 48

What type of chromosomal abnormality leads to the phenotype known as Down syndrome?

Answer 48

trisomy 21

Question 49

An abnormal number of chromosomes can occur due to one particular erroneous meiotic event called:

Answer 49

nondisjunction (chromosomes don't separate).

Question 50

During metaphase II in meiosis, a cell contains ________ of the DNA it did at the beginning of metaphase I.

Answer 50

1/2

Question 51

Sexual reproduction leads to offspring that are all genetically different from one another and from either parent. What are the three aspects of sexual reproduction that lead to this variation?

Answer 51

crossing over during the production of gametes; shuffling and reassortment of homologues during meiosis; and combination of alleles from two parents at fertilization

Question 52

Unicellular organisms

Answer 52

Are all comprised of a single cell

Question 53

Complex multicellularity evolved

Answer 53

Several times independently

Question 54

Which of the following may have led to the evolution of simple multicellularity?

Answer 54

Predation and gene co-option

Question 55

Which of the following is not a feature of simple multicellular organisms?

Answer 55

Few cells are capable of reproduction

Question 56

Which of the following is not a feature of complex multicellularity?

Answer 56

Most cells are capable of reproduction

Question 57

Prokaryotes and eukaryotes are similar in that they both

Answer 57

have DNA and ribosomes

Question 58

What global environmental factor may have promoted the evolution of complex multicellularity?

Answer 58

Increased oxygen concentrations in the atmosphere and oceans

Question 59

How do cells of complex multicellular organisms communicate with each other?

Answer 59

Through direct cell connections | Through genetic signal transduction pathways