AP Biology › Identify evolutionary change mechanisms
Which of the following is not true regarding adaptation?
They result in the divergence of species
It makes an organism better suited to live in a given habitat
It is produced by natural selection
They increase the chance of survival and reproduction
Adaptation can be defined as the gradual outcome of evolution that makes an organism or group of organisms better suited to live in a given habitat. Adaptation is a result of natural selection and increases the chance of survival and reproduction. This outcome can result from either a loss of an ancestral feature or the development of a new trait.
Which of the following best defines interference competition?
Direct competition between individuals through aggression
Indirect competition through a limiting resource
Members of the same species compete for the same resources
Indirect competition between two species hunted by the same predator
Interference competition is a type of competition that occurs directly between individuals through the use of aggression.
Males in a population of frogs compete for territory along the edge of a pond. During mating season, the males guard their territory and croak loudly when females approach. Which of the following types of selection does this most closely resemble?
Sexual selection
Territorial selection
Stabilizing selection
Directional selection
Because the males croak loudly when females approach, this behavior is suggestive of sexual selection. It is likely the males are demonstrating for the females in an effort to attract a mate. Sexual selection occurs when one sex (usually females) choose a mate based on a trait that does not directly affect survival (here, the frog's croak). There is not enough information to determine if the selection is stabilizing, directional, or neither. Territorial selection is not one of the types of a natural selection.
Which of the following is true regarding the process of stabilizing selection?
It decreases genetic diversity
It increases genetic diversity
It has the same impact as disruptive selection
It favors individuals with extreme phenotypes
Stabilizing selection is a type of selection that decreases genetic diversity and stabilizes an optimum trait. In this situation, there is selection against extreme phenotypes. It is the opposite of disruptive selection and similar to purifying selection.
Which of the following was not part of Darwin's theory of evolution?
The inheritance of traits in discrete units called alleles
Organisms that are best adapted to their environments are most likely to survive and reproduce
Over time, traits that are beneficial to an organism in a given environment are likely to accumulate in a population
Organisms of the same species display a variety of different traits
None of these - Darwin did not develop a theory of evolution
The inheritance of traits through discrete units called alleles was not a part of Darwin's theory of evolution. A monk named Gregor Mendel developed the theory of inheritance through alleles. Darwin's theory did not propose a method of inheritance, and Darwin was unaware of Mendel’s work. The works of Darwin and Mendel were later combined by scientists to create the modern theory of evolution.
Which of the following best describes what happens to the frequency of a certain allele in the process of negative selection?
It decreases in frequency
It increases in frequency
There is no change in the allele's frequency
The allele disappears from the gene pool
Negative selection is a type of natural selection in which the frequency of an allele decreases.
Which of the following best describes what happens to the frequency of a certain allele in the process of positive selection?
It increases in frequency
It decreases in frequency
There is no change in the allele's frequency
The allele disappears from the gene pool
Positive selection is a type of natural selection in which the frequency of an allele increases.
Which of the following best represents an example of sexual selection?
Selection for brightly colored plumage to attract female birds
Selection for mechanisms that prevent polyspermy
Selection for antibiotic resistance in microorganisms
Selection for traits that aid in predator avoidance
Sexual selection is selection for traits that confer greater reproductive success. This includes selection for traits that better attract mates.
What is true regarding mutations?
All of these
Duplications, inversions, and translocations are all types of mutations
Mutations are changes to a cell's genome
Mutations may be harmful
Mutations are changes to a cell’s genome and include inversions, duplications, translocations, and deletions, among other unplanned changes to the DNA. Mutations can be harmful to the organism, but can also have beneficial or neutral impacts. Mutation is an important means of evolution because it introduces new genetic combinations into a genome, allowing for the potential of new functions.
Due to the abundance of blue-bellied lizards, they are easier for predators to find. Predators such as hawks become adapted to spotting these blue-bellied lizards and prey on them more frequently than yellow-bellied lizards. When the blue-bellied lizard population begins to decline, the yellow-bellied lizard population begins to rise (due to more abundant resources and the fact that they are preyed on less than the blue-bellies). Which of the following best describes the relationship between the two types of lizards?
Frequency-dependent selection
Heterozygote advantage
Disruptive selection
Intersexual selection
Relative fitness
This relationship displays a frequency-dependent selection. Frequency-dependent selection occurs when the fitness of a phenotype depends on how common it is in the population. When blue-bellied lizards are preyed on the most because they are most abundant, the yellow-bellied lizard population grows quickly. However, as the blue-bellied lizard population declines, predators will begin to prey on the yellow-bellied lizards. As the yellow-bellied lizard population declines, the blue-bellied lizard population will increase, and so on. The number of blue or yellow-bellied lizards depends on the relative amount of lizards of a different phenotype, demonstrating frequency-dependent selection.