ap bio unit 7

Competition for food would probably be most severe between two

Closely related species in similar niches.

Which of the following best explains the observed distribution pattern of the snails?

Dark-colored snails absorb more solar energy and so survive more readily in the colder northern waters.

A small number of lizards from a mainland population have been deposited on four isolated islands because of the effects of a rare strong storm. Which of the following best predicts the outcome of these lizards reproducing for many generations on the islands?

The isolation prevents gene flow; thus, the lizards on different islands experience prezygotic isolation.

All of the following are examples of prezygotic genetic isolating mechanisms EXCEPT:

The progeny of a cross between two different lizard species fail to develop properly.

If the two finch populations are each in Hardy-Weinberg equilibrium and are isolated from each other, then which of the following graphs correctly displays the relative genotype frequencies?

.2, .5, .3

Which of the following phylogenetic trees is most consistent with the data?

3, 4, 2, 1, 5

Assuming that the population was in Hardy-Weinberg equilibrium for the G locus, what percentage of moths in the natural population was white in 1962 ?

4%

In a certain flock of sheep, 4 percent of the population has black wool and 96 percent has white wool. Assume that the population is in Hardy-Weinberg equilibrium. What percentage of the population is homozygous for white wool?

64%

Another hypothesis about the origin of life suggests that life began somewhere else in the universe and arrived on Earth by chance. Which of the following questions might scientists ask to most reliably determine if there has ever been life on Mars?

Did Mars have the elements present in its atmosphere to support life?

Based on the cladogram, which of the following are the traits shared between ferns and pines?

Embryo and xylem only

Which of the following statements might best explain the increase in average beak size in the finch population during the drought?

Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.

For subsequent studies, the researchers wish to determine whether adding a low, sublethal dose of an additional antibiotic causes further decline in the fitness of the bacteria. Which of the following best represents the next step the researchers should take with respect to experimental design?

Group 1: low dose of streptomycin ++ no dose of additional antibiotic Group 2: low dose of streptomycin ++ low dose of additional antibiotic

Using the data in the table, construct a cladogram on the template provided to indicate the most likely evolutionary relationships among the different mammals. Indicate on the cladogram where each of the characters most likey arose in the evolutionary process, and justify the placement of the characters on the cladogram.

Lactose and protein a are a common ancestor to all 5 animals. protein b and casien only arose in the pig/cow/horse branch.

Which of the following data sets is most likely to provide reliable information about the evolutionary relationships among these three snail species?

Location of fossils and shell orientation

Which of the following best explains the directional shift in beak length in these birds?

Longer beaks allow the birds to better access seeds in bird feeders.

Based on the data in the table below, draw a phylogenetic tree that reflects the evolutionary relationships of the organisms based on the differences in their cytochrome c amino-acid sequences and explain the relationships of the organisms. Based on the data, identify which organism is most closely related to the chicken and explain your choice.

Phylogenetic tree: rooted trees with common ancestor, and with snakes, birds, mammals in correct relative order (1 point for tree). Cytochrome c: the more differences in amino acids of cytochrome c, the less closely related, OR fewer differences, more closely related. (1 point) • Penguin is most closely related to chicken. (1 point) • Three amino acids differing between penguin and chicken/penguin has fewest differences from chicken. (1 point)

Which of the following could best explain the change in fur color distribution, as shown in the table above?

The allele for black fur color is unstable, and over twenty years most of the black fur alleles mutated to become alleles for gray fur.

Which of the following statements best explains the changes seen in S. pistillata in response to the changing water conditions?

The corals' adaptation is an example of natural selection because the tolerance is in response to a changing environment and has a genetic basis.

Which of the following best represents the null hypothesis for the experiment detailed in Figure 1 ?

The mating preferences of flies are not dependent on the nutrient source on which they are grown.

For EACH of the four contributions listed above, discuss one example of supporting evidence.

The non-constancy of species: is when within a species there is genetic variation, Ex- peppered moths have variations in color from light brown to dark brown. Branching evolution, which implies the common descent of all species: all mammals have the same bones in their forelimbs, implying a common ancestor. Ex- bats fly but whales swim. Occurrence of gradual changes in species: speciation, a group of finches begins to exhibit different features from those in the rest of the population, including shorter beaks and black stripes on their wings. Eventually, the two distinct groups of birds are considered entirely separate species from one another. Natural selection as the mechanism for evolution: genetic variation may give some individuals an advantage in their environment so they can reproduce to pass down these traits. (antibiotic-resistant bacteria would be a good example)

Which of the following is an appropriate null hypothesis regarding the phenotypic frequencies of this population of salamanders before and after the flood?

The proportions of black, dark-brown, and light-brown salamanders before and after the flood are not significantly different, and any observed differences are due to random chance.

Sugar gliders are native to Australia, and Northern flying squirrels are native to North America. Which of the following best explains the morphological similarities between these two species?

The similarities in traits indicate the species are the result of divergent evolution from a common ancestor that had the same traits that these two species share.

The different fruit preferences of the two fly populations will most likely have which of the following effects?

The single fly species will evolve into two distinct species because of the lack of gene flow between the two populations.

Which of the following pieces of evidence best supports the hypothesis that birds and crocodilians (crocodiles and alligators) are more closely related to each other than they are to other organisms?

The skulls of birds and crocodilians have an opening that is absent in the skulls of other reptiles.

A new bacterial disease, which is easily spread and extremely virulent, affects both populations at the same time. Which of the following is the best prediction of how the new disease will affect the two populations?

The smaller population will be more affected than will the larger population, because the smaller population has less genetic variation than the larger population has.

(a) Explain the theory of evolution by natural selection as presented by Darwin.

a.) Evolution occurs through natural selection. As condition in the environment change, certain traits in a species are favored. Individuals with a trait better fir for the changing environment will in turn produce more successful offspring. As a result, that trait becomes more dominant because those individuals are surviving. The individuals that do not have that trait will eventually die off.

(a) What is the frequency of each genotype (AA, Aa, aa) in this population? What is the frequency of the dominant phenotype? (b) How can the Hardy-Weinberg principle of genetic equilibrium be used to determine whether this population is evolving? (c) Identify a particular environmental change and describe how it might alter allelic frequencies in this population. Explain which condition of the Hardy-Weinberg principle would not be met.

a.) Frequency AA = .36 · Frequency Aa = .48 · Frequency aa = .16 · Frequency dominant phenotype = .84 b.)Allelic frequency changes or five conditions that do not change if population is not evolving. c.) Environmental change identified (1 point) (first one scored) · Explanation of how allelic frequency changed (1-2 points) · Which Hardy-Weinberg condition not met (1 point)

The behaviors of equal numbers of foxes from each population were assessed. Each fox's behavior was scored on a continuum from docile to aggressive based on its interaction with a trained behaviorist. The data is shown in Figure 1. The phenotypic variation in behavior between the two populations can best be described as resulting from

artificial selection

(b) Each of the following relates to an aspect of evolution by natural selection. Explain three of the following.

b.) 1.) CONVERGENT EVOLUTION- Bacteria has an advantage especially because they reproduce so quickly, allowing them to change and evolve. They begin to select the traits that antibiotics do not respond to, and change to eventually become completely resistant. This is the same for insecticide-resistant insects. 2.) NATURAL SELECTION- Isolation is often a way for new species to form. An example would be endemic species, which were isolated from mainland species at one point. They maintained basic characteristics, but had to evolve to a newer geographic environment, ultimately creating a new species. (Reproductive isolation) 3.) SPECIATION- One example of this would be individuals heterozygous with sickle-cell anemia. They do not have both recessive, they do not get too sick to form the disease, but since they at least have one, they are resistant to malaria. This would be an advantage in a population faced with malaria.

Both have fleshy stems adapted for water storage, protective spines, and leaves that are greatly reduced or absent. The similarities between these two families of plants represent an example of

convergent evolution

The table above shows derived characters for selected organisms. Based on the information in the table, which of the following cladograms best represents the evolutionary relationships among the organisms?

fish, amphibians, crocodilians, birds, mammals

The wing of a bat, the flipper of a whale, and the forelimb of a horse appear very different, yet detailed studies reveal the presence of the same basic bone pattern. These structures are examples of

homologous structures

In Darwinian terms, the fittest individuals of a species are those that

leave the greatest number of reproducing descendants

If p equals the frequency of the dominant allele and q equals the frequency of the recessive allele, which of the following terms represents the frequency of the individuals who show the dominant phenotype?

p^2 + 2pq

The fossil record indicates that in some cases reasonably well-defined species appear suddenly and remain unchanged for a long time before they become extinct. This phenomenon is referred to as

punctuated equilibrium

Which of the following factors is the most effective in changing the allele frequency in a natural population?

selection