Unit 7: Evolution and Genetic Diversity

Natural Selection

100

How did different island environments affect Galápagos finch populations over time?

A. The entire finch species became extinct.

B. The finch species adapted by increasing their height.

C. New species of finch formed with varying beak sizes.

D. Migration patterns changed, affecting finch reproductive rates

C. New species of finch formed with varying beak sizes.

200

Which statement best describes Darwin’s theory about evolution?

A. An organism’s traits remain constant from one generation to the next.

B. Traits only become prevalent in a healthy population randomly.

C. Variation naturally exists, and advantageous traits become more prevalent over time in a population.

D. Variation naturally exists, and environmental change does not impact genetic variation in a population.

C. Variation naturally exists, and advantageous traits become more prevalent over time in a population.

Note: Be able to understand that natural selection acts on the variation of traits. Be able to interpret data and recognize what is being acted on to DIRECT the evolution occuring. 

300

Which of the following best explains the importance of phenotypic variation?

A. Phenotypic variation is created by the direct action of natural selection.

B. Phenotypic variation arises in response to changes in the environment.

C. Phenotypic variation is present in a population before natural selection can act upon it.

D. Phenotypic variation helps increase a population’s reproductive success and survival rate.

D. Phenotypic variation helps increase a population’s reproductive success and survival rate.

Note: Certain phenotypes have increased fitness. this means they can better survive in particular environments. For example, how effective plants are at producing fruit. 

400

In which of these examples is artificial selection responsible for reducing diversity?

A. A brushfire blackens tree bark in the forest, and black moths are now more prevalent.

B. Prehistoric farmers bred the wild mustard plant into modern kale, cabbage, and cauliflower.

C. Farmers with the highest quality bulls sell the bulls’ genetic material worldwide for artificial breeding.

D. Each of the Galapagos Islands has a unique species of finch birds with highly specialized diets.

C. Farmers with the highest quality bulls sell the bulls’ genetic material worldwide for artificial breeding.

500

Scientists studied the Magellanic penguins of Argentina (Spheniscus magellanicus) over a period of 27 years. They analyzed phenotypic traits and the percent of chicks that did not survive. A subset of the results showing the relative increased or decreased incidence of traits is shown below.

 

Which statement is best supported by these data and Darwin’s theory of natural selection?

A. Smaller males are more likely to survive in years with high mortality.

B. Smaller females are more likely to survive in years with high mortality.

C. Longer billed males with longer flippers are more likely to survive in years with high mortality.

D. Shorter billed females with shorter flippers are more likely to survive in years with high mortality.

 C. Longer billed males with longer flippers are more likely to survive in years with high mortality.

Evolution of Populations

100

Which of the following can reduce variation in certain gene pools? Check all that apply.

A. natural selection

B. mutation

C. chromosomal changes

D. genetic drift

E. gene flow

A. natural selection

D. genetic drift

E. gene flow

Note: Remember that a decrease in genetic variation (diversity) means that genetic abnormalities can be increased.  What are some ways that genetic abnormalities are increased in small populations?

200

Giraffes live across Africa and generally have the same appearance despite the geographic barriers that separate various populations of giraffes. For a long time, giraffes have been thought to belong to one species, but as scientists tried to save giraffes from extinction, they ran into a problem. A traditional strategy of relocating animals from a healthy population to another area to increase numbers was not working.

Which of the following experiments could the scientists perform to determine whether there are multiple giraffe species that have evolved due to geographic barriers according to the biological definition of species?

A. Examine the morphology of each of the giraffe populations, looking for differences between the various populations.

B. Track the giraffe populations to see if they occupy the same ecological niche within each of the populations.

C. Measure the mating success of giraffes when mating two giraffes from different populations and measure the fitness of any offspring.

D. Analyze DNA from each of the giraffe populations and determine how similar they are to individuals within their own population and other populations.

C. Measure the mating success of giraffes when mating two giraffes from different populations and measure the fitness of any offspring.

300

Which of the following increases variation that natural selection can act upon?

A. mitosis

B. asexual reproduction

C. mutation in gametes

D. mutation in somatic cells

C. mutation in gametes

Note: Mutations can be harmful or beneficial in a population, this allows for natural selection to act upon the mutations. Mutations that are beneficial or allow the organisms to survive and reproduce will increase in the population. 

400

Phenylthiourea, PTC, can be tasted by some individuals but not by others. Students tested everyone in their grade to see who could taste PTC, 100 students total. The ability to taste PTC is a dominant trait. 10 people in the grade were unable to taste PTC. 

Calculate the frequencies of the  recessive allele (q) for the information presented. Round to the nearest hundredth.

0.32

Note: Be sure to know how to calculate p and q from a given population. 

500

The graph shows the population size and amount of genetic variation in the Sarotherodon galilaeus fish population over a period of time.

Overfishing of S. galilaeus in 2008 led to a drastic decline in their population size. Although the population has since increased, the genetic variation in S. galilaeus is still low. At which point on the graph was the population most vulnerable to the bottleneck effect due to a natural disaster and why?

A. Y, because the population is small and there is low genetic diversity

B. Z, because the population is large but the genetic diversity has remained low

C. X, because the population is too large and has exceeded its carrying capacity

D. W, because the population is just starting out and natural selection is still taking place

A. Y, because the population is small and there is low genetic diversity

Lines of Evidence

100

Which statement best explains why a small population is more likely to have changes to allele and genotype frequencies?

A. Small populations are more susceptible to predators or harsh living conditions.

B. Hardy-Weinberg equilibrium controls for genetic drift. Thus, it does not affect genotype frequencies.

C. Random fluctuations can cause frequencies to change more significantly than in larger populations.

D. Random migration patterns tend to be found in small island populations rather than larger populations.

C. Random fluctuations can cause frequencies to change more significantly than in larger populations.

200

Bird and bat wings are analogous due to their wings. They are homologous because of their forelimbs. How is this difference most likely possible?

A. Both animals inherited their forelimbs from a common ancestor.

B. Both of their wings followed the pattern of divergent evolution.

C. Both of their wings were inherited from a common ancestor.

D. Both animals had forelimbs that evolved from a pattern of convergent evolution.

A. Both animals inherited their forelimbs from a common ancestor.

Note: Be sure to know the difference between analogous and homologous structures in bats and birds. 

300

A scientist concludes that land animals evolved from lobe-finned fish. These fish displayed bones in their fins, resembling modern limbs seen in land animals today. In fact, data confirms these fish used their fins to push through very swampy waters, which helped them catch prey more easily. This selective pressure of pushing resulted in adaptation of strong fins to be more common in the population.

Which of the following best describes the type of data selected and why it was used?

A. Morphological data was used to study the structures of the land animals and lobe-finned fish.

B. Geological data was used to study how physical features changed in the environment.

C. Biochemical data was used to study how a mutated gene changed the lobe-finned fish.

D. Geological data was used to study how sedimentary rock created lobe-finned fish fossils.

A. Morphological data was used to study the structures of the land animals and lobe-finned fish.

Note: When using biochemical data scientists can look at DNA, nucleotides, and amino acids sequences. If an amino acid sequence is passed on from a very early ancestor then it is considered a primitive feature. This means that even some of the earliest ancestors possessed the characteristics. 

400

What characteristics below describe the eukarya domain?

A. linear chromosomes in nucleus

B. membrane bound organelles

C. circular DNA

D. unbranched hydrocarbons

E. cell walls

A. linear chromosomes in nucleus

B. membrane bound organelles

D. unbranched hydrocarbons 

Note: Be able to identify traits that LUCA would have. (the common ancestor of all three domains). For LUCA to have the trait, at least two of the three domains should possess the trait. 

500

Which statement best describes the origin of eukaryotes?

A. Eukaryotes first evolved on land where there were open habitats.

B. Archaea and Bacteria microorganisms developed a hybrid organism.

C. Bacteria cells were internalized by early eukaryotic cells, which were probably similar to early Archaea.

D. Bacteria and eukaryotes evolved together, competing with microorganisms in the domain Archaea.

C. Bacteria cells were internalized by early eukaryotic cells, which were probably similar to early Archaea.

Speciation/ Phylogeny

100

What is the difference between prezygotic and postzygotic barriers in speciation? 

A. Prezygotic barriers prevent the formation of a zygote, while postzygotic barriers prevent the development of a mature/fertile offspring.

B. Postzygotic barriers prevent the formation of a zygote, while prezygotic barriers prevent the development of a mature/fertile offspring. 

C. Postzygotic barriers prevent species from mating, while prezygotic barriers do not. 

D. Prezygotic and postzygotic barriers prevent species from mating. 

A. Prezygotic barriers prevent the formation of a zygote, while postzygotic barriers prevent the development of a mature/fertile offspring.

Note: Be sure to understand how hybrid species are formed. For hybrid species to be created both prezygotic and postzygotic barriers must be incomplete. Meaning the two original species are no longer mating or produce fertile offspring. 

200

What is true of sympatric speciation?

A. occurs when a physical barrier geographical separates groups that were once a single population

B. occurs when a population becomes reproductively isolated without a physical barrier.

C. is more frequent than allopatric speciation

D. Gene flow of the population is interrupted when geographically isolated 

B. occurs when a population becomes reproductively isolated without a physical barrier. 

Note: Sympatric isolation occurs when the population no longer mates in the same area, this can be due to sexual selection. 

300

If you were using cladistic analysis to build a phylogenetic tree of cats, which of the following would make the best outgroup?

A. lion

B. rubber plant

C. wolf

D. domestic cat

C. wolf

Note: Be sure you understand how to determine an out group and create a cladogram. You should be able to use a character chart to create a cladogram. 

400

Study the diagram carefully. According to this tree, which two species are most closely related?

A. deer and cow

B. camel and whale

C. hippo and deer

D. peccary and camel

A. deer and cow

Note: Be able to determine common ancestors from a phylogenetic tree. Remember the nodes indicate a speciation event (a common ancestor).

500

The rise and formation of the Isthmus of Panama about 9 million to 3 million years ago separated marine habitats in the Gulf of Mexico and the eastern Pacific Ocean, which had previously been connected. This diagram shows the divergence and speciation of snapping shrimp species giving rise to pairs of sister species as a result of the formation of the Isthmus of Panama.

It can be seen that the formation of sister species had taken a considerably shorter time than the formation of their parental species B and C.

What could be the plausible reasons that led to the much faster speciation due to the formation of the Isthmus of Panama?

1. The genetic flow between populations of parental species had been prevented by the formation of the Isthmus of Panama.
2. The populations of parental species faced a different ecological environment and selection on different sides of the Isthmus of Panama.
3. Before the formation of the Isthmus of Panama, the populations of parental species were under more stringent natural selection in competition for resources.
4. Before the formation of the Isthmus of Panama, the populations of parental species had a lower mutation rate.

A. I and II

B. I and IV

C. II and III

D. II and IV

A. I and II

Diversity

100

Antibiotic resistant bacteria is is able to withstand the use of antibiotics because of its _______?

A. mutation rate

B. speciation

C. genetic diversity

D. population size 

C. genetic diversity 

Note: The genetic diversity of antibiotic resistance bacteria allows it to survive and pass on its resistant genes to other bacteria. The overuse of antibiotics increases the amount of resistant bacteria. When antibiotics are not used, bacteria with the gene are at a disadvantage. This is why scientists suggests circulating antibiotics. 

200

Which statement best describes why a small population is less likely to survive environmental changes?

A. Small populations are less likely to experience gene shuffling.

B. Genetic drift can introduce disadvantageous alleles into the population. 

C. Mutations cannot create novel genetic variations within the small populations.

D. Small populations lack the genetic diversity needed to adapt to environmental change.

D. Small populations lack the genetic diversity needed to adapt to environmental change.

Note: To increase the survival of animals/plants having a wide diversity is essential to survival. 

300

Which of the following are possible sources of the first organic compounds on Earth? Check all that apply.

A. water vapor

B. meteorites

C. fossils

D. inorganic gases 

E. self-replicating molecules

B. meteorites

D. inorganic gases

400

 

A recent United Nations analysis report gathered data on declines in biodiversity across the world. Using the graphs provided, which statement shows an area of concern and is an alternative to the general hypothesis "Humans are responsible for a significant increase in the extinction rate among species in the world today as a result of damage caused to the environment"?

A. Fertilizer use in developing countries should be encouraged to decrease the extinction rate

B. Decreasing air pollution in the least developed countries would decrease species survival rate

C. Protection of key biodiversity areas should be a priority for developed countries to lower the extinction rate

D. Assisting developing countries with more sustainable methods of extraction of living biomass would increase species survival rates

D. Assisting developing countries with more sustainable methods of extraction of living biomass would increase species survival rates

500

Which of the following explains the RNA World Hypothesis?

A. life on Earth arose gradually from inorganic molecules, with amino acids forming first

B. early Earth contained a primitive soup of the inorganic molecules needed to synthesize organic compounds 

C. the world consisted of RNA, a self- replication molecule, before the DNA macromolecule

D. that DNA was the earliest genetic material with RNA following after

C. the world consisted of RNA, a self- replication molecule, before the DNA macromolecule 

Note: From the RNA World Hypothesis, know what a ribozyme is.