Question 1

Because of age estimates of the Tiktaalik fossil species,at approximately 380 mya,it lived

Accepted Answer

The age estimate for Tiktaalik places it in the Phanerozoic eon, specifically the Devonian era, which precedes the appearance of dinosaurs and mammals in the fossil record. Therefore, option C correctly places Tiktaalik's geologic time scale context.

Question 2

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

Placental mammals have a longer gestation period and give birth to more fully developed offspring, which gives them a greater chance of survival compared to marsupial mammals. This advantage helped placental mammals from North America displace many native South American marsupial mammals when a land bridge formed between the two continents.

Question 3

According to fossil evidence,Tiktaalik either crawled or paddled in shallow,tropical streams,approximately 380 mya.These streams may have occasionally become anaerobic,but fossil structures in Tiktaalik indicate it could have what adaptation or selective advantage in these conditions?

Accepted Answer

Tiktaalik's ability to lift and support its head allowed it to breathe air with its lungs, giving it an advantage in shallow streams that may have occasionally become anaerobic. This adaptation allowed it to survive in environments where other aquatic animals may not have been able to survive.

Question 4

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.

Accepted Answer

This statement is true. The fossil record is incomplete because not all fossils have been discovered or preserved. Some may be buried too deep for us to reach, or may have been destroyed by geological processes. Additionally, not all organisms are equally likely to be fossilized, so we may not have a complete record of the diversity of ancient life.

Question 5

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

Accepted Answer

The most common techniques used to study molecular evolution involve comparing nucleotide and amino acid sequences among species. By examining the similarities and differences in these sequences, scientists can infer how closely related different species are and how recently they diverged from a common ancestor. This information can shed light on the processes that drive evolution at the molecular level, including mutation, selection, and genetic drift.

Question 6

Figuer: 
-Najash is an extinct fossil species that has distinct functional pelvis and hindlimbs.Choose the best answer which explains this in evolutionary theory.theory?

Accepted Answer

This is because Najash is a transitional species that shares homologous structures with other vertebrates, such as reptiles. Its distinct functional pelvis and hindlimbs suggest a developmental process that allowed some species of snakes to move from a quadrupedal to a fully limbless form. The presence of homologous structures in Najash supports the theory of evolution, which states that living organisms share a common ancestry.

Question 7

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,then about _____ years have passed since the two species diverged.

Accepted Answer

If substitutions occur at a rate of 2% per million years, then a 10% difference would have taken approximately 5 million years (10% / 2% per million years = 5 million years) since the two species diverged.

Question 8

If many genes from two species differ in about 5% of their bases and substitutions occur at an estimated rate of 5% per 1 million years,then about _____ million years have passed since the two species diverged.

Accepted Answer

The answer of If many genes from two species differ...

Question 9

Figuer: 
-A phylogenetic tree is shown in part (b)of the image above.Phylogenetic trees visually represent hypotheses of the evolutionary relationships and ancestry of species or species groups.In this case,Najash is placed in proposed context with other snake species,representing different groups of snakes around the world.What can you conclude about the evolution of sea snakes and the Najash species?

Accepted Answer

The phylogenetic tree illustrates evolutionary relationships, suggesting that both Najash and the three fossil marine snakes share a common ancestor, indicative of a shared evolutionary origin.

Question 10

Earth's history spans about 4.5 billion years.

Accepted Answer

This is the accepted age of the Earth based on scientific evidence.

Question 11

The abundant presence of ammonite fossils,corals,sponges,and crinoids in a large area indicate that the area was once part of an ocean.

Accepted Answer

Ammonite fossils, corals, sponges, and crinoids are all marine organisms and their abundance in a large area suggests that the area was once underwater as part of an ocean.

Question 12

Dinosaurs devoloped,became diverse and eventually became extinct during the Paleozoic era.

Accepted Answer

Dinosaurs actually evolved and thrived during the Mesozoic era, which followed the Paleozoic era.

Question 13

Figuer: 
-If,according to one hypothesis,Najash evolved from terrestrial,burrowing snakes,which of the following best reflects the adaptive or selective benefit for other snakes to have lost their pelvis and hindlimbs?

Accepted Answer

Losing the hindlimbs and pelvis would have allowed snakes to move more easily through confined spaces such as tunnels and burrows. This would have given them an advantage when pursuing prey or avoiding predators in these environments. Swimming ability (B), digging ability (D), and grasping prey (E) are not directly related to the benefits of losing the pelvis and hindlimbs. While increased speed (A) is a possibility, the hypothesis specifically suggests that Najash evolved from burrowing snakes, and speed may not have been a primary selective pressure in that environment.

Question 14

The common skeletal organization between two vertebrate animals,with bony limbs used for movement,is a example of analogous structures.

Accepted Answer

The common skeletal organization between two vertebrate animals is an example of homologous structures, not analogous structures. Analogous structures are those that have similar functions but different evolutionary origins. Homologous structures, on the other hand, have the same evolutionary origin but may have different functions. In this case, the bony limbs used for movement in both animals have a common evolutionary origin, making them homologous structures.

Question 15

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

Accepted Answer

Once two species diverge, they usually evolve separately and can no longer interbreed. As a result, they cannot exchange genetic material and different mutations can accumulate in each species over time.

Question 16

The hypothesis that birds are closely related to small dinosaurs called theropods began with the discovery of the fossilized skeleton of Archeopteryx.

Accepted Answer

The discovery of the fossilized skeleton of Archeopteryx in the late 1800s was one of the earliest pieces of evidence suggesting that birds evolved from theropod dinosaurs. Since then, numerous other fossil discoveries have provided further support for this hypothesis.

Question 17

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

Marsupial mammals moved into North America from South America during the Cenozoic era, not because ocean levels dropped 70 million years ago. The major migrations and displacements of mammal species, including the interchange between North and South American faunas, occurred much later, primarily due to the formation of the Isthmus of Panama around 3 million years ago, rather than due to changes in ocean levels 70 million years ago.

Question 18

Figuer: 
-Fossil evidence shows that Tiktaalik had both lungs and gills,indicating that it could

Accepted Answer

Fossil evidence suggests that Tiktaalik had both lungs and gills, indicating that it could absorb oxygen from both air and water. This feature would have allowed Tiktaalik to survive in both aquatic and terrestrial environments.

Question 19

One line of evidence that humans arose in Africa is the observation that

Accepted Answer

Mitochondrial DNA is passed down maternally, and studies have shown that African populations have the most diverse mitochondrial DNA sequences, supporting the theory that humans arose in Africa.

Quiz 13: Evidence of Evolution