The Galápagos woodpecker finch uses cactus spines to remove insects hidden deep inside tree bark. Finches that were better able to extract insects survived and reproduced more successfully than others.

Which selective pressure most likely led to this behavioral adaptation?

Wild mountain goats reproduce only once per year instead of continuously throughout the year.

What is the most likely evolutionary explanation for this seasonal breeding pattern?

According to the principles of natural selection, which of the following is most likely to result in speciation?

The African fish eagle (a) looks very similar to the American bald eagle (b).

Which of the following statements provides the best evidence that the African fish eagle and American bald eagle are distinct biological species?

The Greater Prairie Chicken population in Illinois declined to fewer than 50 individuals due to natural disasters and agricultural development. As a result of inbreeding, many birds showed genetic defects that reduced fertility and survival rates. To address this issue, prairie chickens from neighboring states were introduced into the Illinois population to allow interbreeding. The resulting hybrid offspring showed increased genetic variation and higher reproductive success compared to the original population.

Which table best represents the mechanism of evolution and the effect on the gene pool of the Greater Prairie Chicken population?

The Aeshna anax or dragonfly has a detailed fossil record in which the lengths of wings and limbs (legs) have developed gradually over millions of years as shown below.

Which statement is best supported by this information?

This cladogram shows the evolutionary relationships among some organisms based on homologous structures.

Which statement is supported by this cladogram?

A new species of lion is introduced to a savannah where zebras live. Although the lions are fast, some zebras are able to outrun and escape the new predator.

Which of the following best predicts what will happen to the zebra population over time after the lions are introduced to their ecosystem?

The "Clean Air Act" was passed in 1970 to combat heavy pollution. After the bill passed, scientists collected data on a local moth population. The table below shows the survival rate of two types of moths in the same environment over a period of four years.

Which statements about the moths in this environment is best supported by the data?

Select TWO correct answers.

Natural selection favors traits that improve an organism’s success in its environment. In evolutionary terms, which situation best represents high biological fitness?

Some species of bacteria reproduce asexually by binary fission. However, they can also exchange DNA through processes such as conjugation, transformation, or transduction.

How does the exchange of DNA between bacteria help populations survive environmental changes?

The bar graph shows the frequency of the dark-fur allele in a population of field mice before and after a wildfire. After the wildfire, the habitat consisted mostly of dark soil and rocks.

Which factor BEST explains the change shown in the graph?

The graph shows the average fur thickness of a population of arctic foxes over several decades. During this time, winters on the island became longer and colder.

Which question would be MOST important for scientists to answer to determine whether natural selection caused the increase in average fur thickness?

A species of lizards can be found in both light-colored sandy deserts and darker volcanic rock regions in the southwestern United States. The lizards in sandy environments tend to have lighter scale coloration, while the lizards living on dark rocks have darker scales. The difference in coloration affects how easily predators can detect the lizards in their environments.

Scientists studied variation in two pigmentation genes, TYR and OCA2, in populations from both habitats. The table shows allele frequencies for these genes in each population.

Which evidence would BEST support the claim that the phenotypic distribution observed in these populations of lizards are a result of natural selection?

The diagram below shows the morphological change in two species of lizards.

Which statement explains why species 1 and species 2 are different?

Conservation biologists studying an island population of foxes discovered that the population has very low genetic diversity due to a severe population genetic drift bottleneck effect.

Which outcome is most likely to result from the fox population’s low genetic diversity?

Certain species of the coral-like sea organisms called bryozoans first appeared about 140 million years ago. They remained unchanged for the first 40 million years and then suddenly experienced rapid genetic change.

Which process would BEST account for the pattern of evolution of bryozoans?

Current day, scientists estimate there to be approximately 8.7 million different species of eukaryotes living on Earth including animals, plants, and fungi. It is estimated that 80% of species are yet to be discovered!

The graph below shows an estimate of the number of species that existed millions of years ago.

Select TWO true statements based on information provided in the graph.

Categorize the following as either Punctuated equilibrium or Gradualism.

Which two organisms share the LEAST common ancestor with Organism Kiwi?

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Below is a diagram of a phylogenetic tree on DNA similarities of five organisms.

Which lettered location on the phylogenetic tree identifies characteristics shared by species X, Y and Z?

African elephants, Asian elephants, and their extinct relatives, such as mammoths, all belong to the same taxonomic family, Elephantidae. Members of this family share characteristics such as large ears, tusks, a long trunk, and pillar-like legs. Despite their similarities, African and Asian elephants have distinct features, including differences in ear size, tusk shape, and trunk structure.

The physical features of animals in this family and the family's geographical origin provide evidence that all of these animals...

A population of lizards once inhabited a continuous stretch of tropical forest. However, over thousands of years, a wide river formed, dividing the forest into two separate regions.

As a result, the lizard population was split into two isolated groups, preventing gene flow between them. Over time, due to differences in environmental conditions and natural selection, the two groups developed distinct coloration, body size, and mating behaviors.

When researchers later attempted to reunite the two groups, they found that the lizards no longer recognized each other as potential mates and could not interbreed.

Which evolutionary process best explains the formation of these two distinct lizard species?

Scientists have observed that two closely related species of cichlid fish live in the same lake but occupy different ecological niches. One species primarily feeds on small insects near the surface, while the other species specializes in eating crustaceans from the lake bottom. Despite living in the same body of water, these two species have developed distinct physical and behavioral traits over time, leading scientists to believe they evolved from a common ancestor.

• Are these two cichlid fish able to reproduce with each other?

• What type of speciation has occurred?

Think about the questions carefully. Then enter your answer and your explanation in the box provided.

Why did the darker-colored beetle population decrease over time?

The cross-pollination of flowers will most likely result in-