Evolutionary Relationships
A scientist is trying to determine the relationship between clams, snails, and squid. When she generates a molecular clock, she is surprised to see that clams and squid are more closely related than clams and snails. Which did the molecular clock data show?
Clams and squid have been evolving separately for a shorter time than clams and snails.
Scientists notice structural similarities between fossils of a land animal and an aquatic organism. They know the similarities are not a result of the two organisms having to adapt to similar environments. What can they attribute the structural similarities to?
common ancestry
Which best describes biogeographic isolation?
It is a mechanism for evolution.
Which type of selection leads to increased phenotypic and genetic variation?
disruptive selection
Consider the picture on question 20. A bird that preys on moths is introduced to the habitat with moths and trees like the ones in the picture. What will most likely happen to the population of moths in this habitat?
The moths will evolve from dark to light due to a selective pressure.
Consider the cladogram on question 2. A fossilized fish is found that has jaws but no true bones. Where does this fossil belong on the cladogram?
B
Why are the Miller-Urey experiments essential to the theory of evolution?
They showed how organic molecules could be made from Earth's early atmosphere.
Which of the following is an example of reproductive isolation?
two populations of finches that cannot produce viable offspring
Consider the graph on question 18. Babies with very low or very high birth weight are less likely to survive. The graph shows the percentage of babies born at different weights. Which statement is a valid claim that could be made using the data in the graph?
Stabilizing selection is occurring because the average is favored.
Consider the picture on question 21. Which of Charles Darwin’s main points is depicted in the image?
Organisms within a population compete with each other to survive.
In a cladogram, when does a group of organisms branch off?
when a new trait evolves
Thylacosmilus is a marsupial, and Smilodon is a mammal. Thylacosmilus and Smilodon both have saber teeth, but they do not share an ancestor that had saber teeth. What are saber teeth for these organisms?
analogous structures
Horses and zebras can be bred to produce a zorse, which is infertile. Which is most likely the reason zebras and horses are considered separate species?
Their offspring cannot breed.
A biology teacher asks students to give examples of genetic variations that support the idea that changes in a population’s environment affect genetic variation. Which is the least supportive example?
changes in genetics in human populations
Which best illustrates a result of natural selection?
giraffes having increasingly longer necks over time
Mr. Morales is teaching a lesson on classification. He says that spiders are classified as a different group than insects because they have eight legs instead of six legs. He explains that spiders evolved first. Mr. Morales also says that having eight legs is the derived trait that separates the two groups. Antonio thinks Mr. Morales is wrong. Which piece of information is Antonio considering?
If spiders evolved first, six legs is the derived trait.
Which best describes the fossil record?
The fossil record provides evidence of a common ancestor to many species.
Evolution is change in a population over time and includes the gene pools of that population. How does biogeographic isolation allow for the change of gene pools over time?
Biogeographic isolation causes changes in gene pools that result from populations being separated.
Henry was studying two populations of the same species of lizards. One population lived on an island and the other lived on the mainland. Both populations were affected by a hurricane that hit the island and the mainland with equal force. A year later, Henry was testing the gene frequency and saw a decrease in genetic variation in the island species, but not in the mainland species. Which best describes a conclusion he might have reached?
Genetic drift greatly affects small populations, but large populations can recover.
A male cardinal’s red color is an example of a trait affected by natural selection. The females of the species choose mates based on the vibrant colors of the males’ feathers. If females begin using different criteria than feather color when they choose mates, what would most likely happen to the color of the male cardinals over time?
increased variation in the shades of red because there is no advantage in one specific color
Does evolution occur in individuals or in populations?
Populations
Jezelyn needs to create a project that shows geographic isolation in action and decides to make a video. Which of the following would make the best project?
a video that shows a large river that has penguin populations on both sides
A student has written a paper about a deer population that was separated when a canyon developed between members of the group. In her paper, she showed that the two groups adapted differently and can no longer interbreed. What would be the best title for her paper?
Speciation by Geographic Isolation
Which of the following best defines a gene pool?
the sum of all genetic traits in a population’s individuals at a given time
Charles Darwin hypothesized that some individuals would be better equipped for survival than others, and that those that were less equipped would not survive. Darwin formulated this hypothesis based on the work of which scholar?
Thomas Malthus, who studied population growth