Question 1

Which piece of evidence did Darwin observe during his 5-year journey aboard the HMS Beagle?

Accepted Answer

During his journey, Darwin observed that the finches on the Galápagos Islands had varying beak shapes and sizes, which he hypothesized were adaptations to the different available food sources on each island. Later, he found a South American species of finch with similar variations in beak shape and size, which led him to believe that the Galápagos finches had descended from this species and undergone adaptive radiation.

Question 2

During sympatric speciation

Accepted Answer

During sympatric speciation, reproductive isolation occurs between certain subpopulations even though they are living in the same geographic area. This can happen through various mechanisms such as changes in mating behavior, differences in ecology or niche specialization leading to different mating preferences, or polyploidy. Wide phenotype differences may or may not develop between subpopulations, and geographic separation is not a requirement for this type of speciation. Mutations may contribute to the differences between subpopulations, but they are not the sole cause.

Question 3

An insect population lives along the edge of a north-south mountain range.The populations from the east and west slope eventually join in a low northern pass and interbreed,producing fertile offspring; but they do not circle around the southern edge because of a desert barrier.When glaciers move southward,the populations are pushed south of the northern pass and are isolated.While isolated,the two populations develop enough differences over time that when the glaciers retreat north and the insects again share the same pass,they no longer mate at the same time,nor can they produce fertile offspring.These insects

Accepted Answer

The isolation of the two populations caused them to develop enough genetic differences to become separate species. Therefore, they were originally one species but are now two different species.

Question 4

The difference between phyletic gradualism and punctuated equilibrium is that

Accepted Answer

Phyletic gradualism is the idea that evolution occurs slowly and gradually over time, while punctuated equilibrium suggests that speciation can occur relatively quickly in bursts, followed by long periods of stability. Therefore, option B is the correct answer. The other options are incorrect because they either provide false information or are not supported by the theory of phyletic gradualism and punctuated equilibrium.

Question 5

Phylogeny refers to the

Accepted Answer

Phylogeny refers to the evolutionary history of a species, including the relationships between different species and how they evolved over time. It involves the study of genetic and morphological similarities and differences to understand the evolutionary relationships among organisms.

Question 6

In the case of Darwin's finches,an ancestral finch species from the mainland arrived on the Galápagos Islands and soon developed into many new species via adaptive radiation.The finches did NOT undergo adaptive radiation back on the mainland.What is the most plausible biological explanation?

Accepted Answer

Competition from many other bird species on the mainland provided stabilizing selection that was absent on the islands, allowing for more diverse adaptations to emerge via adaptive radiation.

Question 7

In a cladogram,clades are groups of related organisms.In the past,phylogeneticists built clades using the idea of parsimony,that the pattern that uses the fewest evolutionary changes is the most likely to be correct.Today,with the use of computers and DNA sequences,the explanation that is thought to be the best is

Accepted Answer

Today, with the use of computers and DNA sequences, the explanation that is thought to be best is the one that shows the fewest changes in the nucleotide sequences. This is because the fewer the changes in the nucleotide sequences between two species, the more closely related they are thought to be.

Question 8

The three-domain system is primarily based on

Accepted Answer

The three-domain system is primarily based on molecular data showing prokaryotes are far more diverse than previously thought. It separates the prokaryotes into two separate domains, Archaea and Bacteria, due to significant molecular differences. Eukaryotes make up the third domain.

Question 9

What information is contained in the branches of a cladogram?

Accepted Answer

The branches of a cladogram represent a recent common ancestor and all of its descendants. This is because a cladogram is a diagram that shows evolutionary relationships based on shared derived characteristics, and a recent common ancestor gave rise to all of the descended species in the branch.

Question 10

Once a true cell was formed,biological evolution began.Biological evolution is all the changes that have occurred in living things since the beginning of life due to differential reproductive success.This means that

Accepted Answer

The statement "living things have all evolved from a common ancestor" is the correct explanation of biological evolution. It is widely accepted in the scientific community that all living organisms share a common ancestor and have undergone changes through differential reproductive success over time. Options A, B, D, and E are all incorrect as they do not accurately describe the process of biological evolution.

Question 11

Which of the following would NOT result in reproductive isolation?

Accepted Answer

Genetic identity alone does not necessarily result in reproductive isolation. There needs to be some sort of barrier preventing interbreeding, such as geographic or behavioral barriers.

Question 12

Different species of female fireflies flash different patterns during mating season.This is an example of _________ isolation.

Accepted Answer

Behavioral isolation is a type of prezygotic isolation where individuals of different species have different mating behaviors or rituals, preventing them from successfully interbreeding. In this case, different species of female fireflies flash different patterns during mating season, which acts as a behavioral barrier to mating between different species of fireflies.

Question 13

The model of speciation that requires some time with geographic barriers between two populations,allowing evolution of reproductive isolation,is

Accepted Answer

Allopatric speciation is the model of speciation that requires geographic barriers to exist between two populations for an extended period of time. The geographic barriers lead to reproductive isolation, and the populations diverge enough to become distinct species. This process takes place over a long period of time and is therefore considered a type of gradualism.

Question 14

You are traveling across the Pacific Ocean when you come across a small island,island #1.There is lush vegetation and several species of beetles that vary in the color of their carapace.The colors you find are green,blue,purple,and black.A second island,200 miles closer to the mainland (island #2),is mostly sand with some palm trees and has a single species of beetle that has a brown carapace.You examine the colored beetles and discover that they are all related and that they are related to the brown species on the second island.Which of the following is the most likely scenario?

Accepted Answer

The brown beetle migrated to island #1 and gave rise to the colored species on island #2 through adaptive radiation.

Question 15

Phylogenetics uses evolutionary trees called cladograms to arrange species into clades,or related groups,showing all of the descendents of a common ancestor.The branches of the tree are based on all but which of the following?

Accepted Answer

Cladograms are based on shared derived characteristics, homologous structures, morphology, and DNA sequences. Convergent evolution (choice B) is not used to arrange species into clades because it is a result of unrelated species evolving similar characteristics due to similar environmental pressures, rather than due to a shared common ancestor.

Question 16

Gulls recognize their own species by the type of ring around the eye.This is an example of

Accepted Answer

This is an example of behavioral isolation, as the gulls are able to distinguish their own species based on a specific behavior (recognition of the ring around the eye) and are less likely to mate or interact with individuals of other species. Geographical isolation involves physical barriers that prevent organisms from interbreeding, ecological isolation occurs when organisms occupy different niches or habitats, physiological isolation involves physical or biochemical differences that prevent reproduction, and temporal isolation involves differences in reproduction timing. None of these concepts are applicable in this scenario.

Question 17

According to the proposed three-domain system,

Accepted Answer

The three-domain system, proposed by Carl Woese, divides cellular life forms into archaea, bacteria, and eukarya. It suggests that archaea and eukarya share a more recent common ancestor with each other than either does with bacteria, based on differences in their ribosomal RNA sequences.

Question 18

During allopatric speciation

Accepted Answer

Allopatric speciation occurs due to a geographic separation between subpopulations, which creates reproductive isolation and leads to divergence in traits over time. Gene flow decreases or stops altogether between the separated subpopulations.

Question 19

All living organisms share characteristics such as DNA,the molecule that passes information between generations; metabolic processes like glycolysis,and the ability to utilize specific energy sources.This is thought to be due to

Accepted Answer

The shared characteristics among all living organisms are thought to be due to biological evolution, which has resulted in the conservation of key genetic and metabolic processes that have allowed for the survival and proliferation of living organisms over time. Limited environmental stimuli, the presence of transitional forms, postzygotic isolation, and prezygotic isolation may all play a role in evolution and species differentiation, but they do not explain the fundamental shared characteristics among all living organisms.

Question 20

The new model of evolution that proposes that organisms spend most of their time in fairly unchanging form and undergo occasional bursts of speciation is called

Accepted Answer

The new model of evolution that proposes that organisms spend most of their time in fairly unchanging form and undergo occasional bursts of speciation is called punctuated equilibrium. This model contrasts with phyletic gradualism, which suggests that evolution occurs at a steady pace over a long period of time.

Quiz 27: Evolution of Life