Question 1

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 bones are vestigial.Please see section 13.4 for more information.

Question 2

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.Please see section 13.6 for more information.

Question 3

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.Please see section 13.1 for more information.

Question 4

Within the country of Indonesia,the island of Sumatra has tigers and rhinos,while to the East,the island of Sulawesi has cockatoos and tree kangaroos.What is the best explanation for this observation?

Accepted Answer

The animals listed for Sumatra are placental mammals,while those listed for Sulawesi are marsupials.Please see section 13.3 for more information.

Question 5

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.Please see section 13.4 for more information.

Question 6

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.Please see section 13.3 for more information.

Question 7

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.Please see section 13.4 for more information.

Question 8

Placental mammals give birth to more fully developed offspring than marsupial mammals and therefore have a greater chance of survival.This helps to explain why placental mammals from North America displaced many native South American marsupial mammals when a land bridge formed between the two continents.

Accepted Answer

More advanced young at birth have a phenotype which is promoted by natural selection over the less advanced young of marsupials selected.Please see section 13.3 for more information.

Question 9

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.Please see section 13.4 for more information.

Question 10

Dinosaurs lived essentially during the Paleozoic era.

Accepted Answer

Dinosaurs lived during the Mesozoic.Please see section 13.1 for more information.

Question 11

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.Please see section 13.1 for more information.

Question 12

In a fruit fly embryo,the homeotic gene Antp determines where legs grow.When the promoter of Antp is mutated,flies grow legs from their head instead of antennae.In this mutation

Accepted Answer

If legs appear unexpectedly,AntP must be acting in that place.Please see section 13.5 for more information.

Question 13

Evolution occurs in

Accepted Answer

While there is a role for alleles,individuals,and other things in evolution,evolution itseld is about the divergence of one species from another.Please see section 13.6 for more information.

Question 14

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.Please see section 13.6 for more information.

Question 15

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.Please see section 13.5 for more information.

Question 16

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.Please see section 13.2 for more information.

Question 17

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.Please see section 13.6 for more information.

Question 18

When ocean levels dropped about 70 million years ago,marsupial mammals moved into North America and displaced many of the placental mammal species.

Accepted Answer

The movement of marsupials into North America occured millions,not tens of millions,of years ago.Please see section 13.3 for more information.

Question 19

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.Please see section 13.6 for more information.

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 possums.Please see section 13.3 for more information.

Quiz 13: Evidence of Evolution