Question 1

-In the section "Investigating Life: Evolving Backwards," what was hypothesized about the loss of legs in modern-day snakes?

Accepted Answer

Various hypotheses have been advanced over time to identify the ancestors of snakes.

Question 2

The number of differences between cytochrome c of humans and cytochrome c of other organisms is as follows: Rhesus monkey - 1 difference; pigeon - 12 differences; fruit fly - 24 differences.The order in which these species are most similar to humans is

Accepted Answer

Evolutionary closeness can be seen in the gene sequence differences between organisms.

Question 3

Dinosaurs lived during the Paleozoic era.

Accepted Answer

Dinosaurs lived during the Mesozoic.

Question 4

The femur in a snake and pelvis in a whale are examples of

Accepted Answer

Whales and snakes have lost functional limbs, so the remnant femur and pelvis bones are vestigial.

Question 5

The wings of a bat and an insect are examples of

Accepted Answer

Since bat and insect wings are derived from completely different structures, they are considered analogous.

Question 6

The fossil record is often incomplete,in part because scientists will never be able to discover some of the fossils that are buried deep in the earth and in part because some living things fossilize more readily than others.

Accepted Answer

The fossil record is very valuable, but its incompleteness requires caution from scientists.

Question 7

The observation that most aquatic animals,like fish,penguins,and whales,all have streamlined bodies and fins or flippers for steering are a result of

Accepted Answer

Many aquatic animals from very different lineages have converged on streamlined bodies as an effective solution for moving through the water.

Question 8

The techniques used to study molecular evolution are based on the comparison of nucleotide and amino acid sequences among species.

Accepted Answer

Sequences diverge over time in different species, giving some idea of just how distantly related species are.

Question 9

In a fruit fly embryo,the end that becomes the head contains high amounts of the protein bicoid.What may happen if you injected high levels of bicoid in the other end of the embryo?

Accepted Answer

The injection of extra bicoid protein out of its usual place would disrupt normal pattern formation.

Question 10

If you were looking for a time line of Earth's history,you would need one spanning about 4.6 billion years.

Accepted Answer

Earth has existed for billions of years, but life has been on land for only a small fraction of that time.

Question 11

If many human genes differ in about 10% of their bases from another species' same genes and substitutions occur at an estimated rate of 2% per one million years,approximately how many years have passed since the two species diverged?

Accepted Answer

Combining fossil data with molecular data allows us to time the divergence of different groups of organisms.

Question 12

When a land bridge formed about 70 million years ago,marsupial mammals moved into South America and displaced many of the placental mammal species.

Accepted Answer

Placental mammals displaced many of the marsupial mammals in South America beginning around 2 million years ago.

Question 13

Why do different mutations accumulate in two species once they diverge?

Accepted Answer

Two non-mixing gene pools cannot homogenize by mating and remain similar-they diverge in the sequence of their genes.

Question 14

The wings of a bat and a bird are examples of

Accepted Answer

Since wings are derived, in bats and in birds, from forelimbs of vertebrates, they are homologous.

Question 15

If many genes from two species differ in about 5% of their bases and substitutions occur at an estimated rate of 5% per one million years,approximately how many years have passed since the two species diverged?

Accepted Answer

Putting timing on the separation of species based, in part, on gene sequence data, is known as using a molecular clock.

Question 16

-In the section "Investigating Life: Evolving Backwards," how did the scientists test the hypothesis?

Accepted Answer

Fossils can be a great help in seeing connections between ancestors and current animals, using the anatomy of each for comparison.

Question 17

Placental mammals give birth to more fully developed offspring than marsupial mammals and therefore have a greater chance of survival.

Accepted Answer

More advanced young at birth have a phenotype which is promoted by natural selection over the less advanced young of marsupials.

Question 18

Amphibians,birds,and mammals look the most similar as

Accepted Answer

Similar embryogenesis results from similar patterns generated by gene expression and provides significant clues about how organisms are related.

Question 19

The abundant presence of ammonite fossils in a large area indicates that the area was once part of an ocean.

Accepted Answer

Ammonites are oceanic creatures, so their presence in a place indicates the former existence of an ocean there.

Question 20

The fossil record indicates that at one time marsupials were common to both Australia and South America,but today most South American marsupials have become extinct.The most probable explanation for marsupials being common to Australia yet not very common to South America today is that

Accepted Answer

Most marsupials have disappeared from the Americas, with the exception of some types of opossums.

Quiz 13: Evidence of Evolution