AP biology macroevolution
One of the oldest known mammalian fossils belongs to a small furry species, Hadrocodium wui, that lived 195 million years ago. For the following 100 million years, only a small number of groups of mammalian fossils are found in the fossil record. By 65 million years ago, the nonavian dinosaurs were extinct. By 55 million years ago, there were 130 mammal genera, including 4,000 different species that occupied a wide variety of habitats. Which of the following best describes the cause of the rapid increase in the number of mammalian species between 65 and 55 million years ago?
After the dinosaur extinction, many ecological niches became available, leading to the adaptive radiation of mammals.
Which of the following best predicts how phylogenetic relationships might be revised if transposon 1 was not found in chimpanzees?
Chimpanzees would be more closely related to humans than to bonobos.
Paleoclimatic analysis has generated a claim that there is a possible correlation between an extinction event around 29 million years ago that allowed grasslands to become abundant and the adaptive radiation of several groups of butterflies. Which of the following proposes the best alternative hypothesis for the claim?
Climate analysis conducted by sampling pollen preserved in amber shows an increase in grass pollen 29 million years ago, which indicates there was an increase in grasslands that correlates to an increase in butterfly speciation during the same time period.
Which of the following experiments would be most appropriate to determine whether populations of S. aureus are continuously adapting in order to obtain iron from hosts more effectively?
Culture S. aureus bacteria with hemoglobin from a novel host species as the only source of iron for many generations, then compare protein structure from bacteria in this culture with bacteria from the original culture.
Which of the following data could best support the claim that species B arose from a speciation event in Lake I?
DNA analysis shows fewer differences between species A and species B in Lake II than between species B and the populations in Lake II
Finch beak depth was measured before and after a severe drought in 1977. The averaged results are shown in Figure 1. After the drought, there were fewer seeds available for the finches to eat and the seeds that did remain were larger and harder to crack open. Researchers claim that when large, hard seeds are the predominate food source, the average beak depth of these finches tends to increase in subsequent generations. Using the evidence provided, which of the following best justifies the researchers' claim?
Finch beak depth increased as a consequence of selective pressure after the drought because the remaining seeds were larger and harder.
Low doses of antibiotics are often added to livestock feed to increase production. Studies have shown that bacterial populations constantly exposed to the sublethal doses can evolve resistance to the antibiotics. A research group claimed that when a population of bacteria are constantly exposed to sublethal doses of streptomycin, their fitness declines due to the increased energy requirements for survival in the presence of the antibiotic. 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 antibioticGroup 2: low dose of streptomycin ++ low dose of additional antibiotic
Which of the following best explains how the ecological conditions are likely to be different in the two models?
In model A the ecological conditions change gradually over a long period of time; in model B the ecological conditions remain unchanged for long periods of time and then change drastically.
Which of the following best justifies the claim that alleles that may be adaptive in one type of environment can be deleterious in another because of different selective pressures?
Light-colored mice are significantly more susceptible to predation by owls in habitats with lava rocks than in habitats with sandy soil.
Researchers observed selected internal structures of four different microscopic organisms as part of a larger study on the divergence between eukaryotes and prokaryotes. Their observations are recorded in Figure 1. Which organism would the researchers most likely predict to be the most distantly related to eukaryotes?
Organism 1
Researchers examined the ability of cultures of the bacterium Pseudomonas aeruginosa to adapt to the antibiotics ceftazidime and avibactam when they are administered together. The researchers grew four replicate cultures in growth medium with no antibiotics added (control) and four additional replicate cultures in the same growth medium with added ceftazidime and avibactam. At the conclusion of the experiment, samples of the replicates exposed to the antibiotics were removed and their genomes were sequenced. All of the antibiotic-resistant mutants were missing three genes (hmgA, galU, mexXY). It is known that one of these three genes makes wild-type P. aeruginosa susceptible to the two antibiotics. However, the researchers do not know which gene it is. Which of the following experiments would specifically determine which gene is responsible for ceftazidime-avibactam sensitivity in P. aeruginosa ?
Perform gene knockout (targeted mutation) of either the hmgAhmgA, galUgalU, or mexXYmexXY gene on separate cultures of the wild-type P. aeruginosa. For each individual mutant, determine whether or not ceftazidime-avibactam resistance has occurred.
A scientist is attempting to provide support for the hypothesis that RNA was the first genetic material. Which of the following would be a workable alternate hypothesis?
RNARNA can be observed to self-replicate without the assistance of proteins, while DNADNA always requires protein-based enzymes to replicate.
Which of the following mechanisms could most likely account for the origin of species B in Lake I?
Sympatric speciation
Which of the following best provides reasoning supporting a method that would help protect commercial banana crops from infection by pathogenic organisms such as Fusarium fungi?
The commercial banana strains should not be grown in monocultures, since many pathogenic organisms are able to evolve rapidly in response to a single selective pressure.
Some scientists claim that amphibians are currently experiencing a period of mass extinction. Which of the following should be included in an alternative hypothesis that would best support this claim?
The current extinction rate of amphibians compared with the background rate of extinction as determined by the fossil record
Female European corn borer moths (Ostrinia nubilalis) produce the sex pheromone 11−tetradecenyl acetate (11−TDA), which attracts males of their species. 11−TDA can be produced in two forms, E and Z, each with a different three-dimensional shape. Researchers have discovered two different strains of the European corn borer moth living in the same area. Females of the E strain produce primarily the E form of 11−TDA and females of the Z strain produce primarily the Z form of 11−TDA. Males of both strains are more attracted to the form of 11−TDA produced by the females of the same strain. Which of the following best predicts a long-term effect of the differences between the E and Z strains?
The difference between the forms of the sex pheromone 11−TDA11−TDA produced by EE and ZZ strains will act as a prezygotic reproductive barrier leading to sympatric speciation.
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.
Many scientists claim that the synthesis of the first organic molecules from inorganic precursors was possible because of the highly reducing atmosphere found on primitive Earth. Which of the following is an appropriate null hypothesis that could be used when investigating the claim?
The synthesis of organic molecules from inorganic molecules is possible under current atmospheric oxygen levels as well as those found on primitive Earth.
Dr. Robert Hazen has worked to develop a hypothesis that explains the origin of life on Earth. His work has focused on hydrothermal vents, which are cracks in the ocean floor. Water heated by molten rock beneath the crust escapes from these vents at very high temperatures, producing hot, high‑pressure environments at the vents on the ocean floor. In order to provide evidence that these vents may be areas where life originated, which of the following states a null hypothesis Hazen might have used to begin his research?
The temperatures and pressures found in hydrothermal vents resemble conditions described in currently accepted origins of life hypotheses.
Which of the following is the null hypothesis most relevant for evaluating the data in Table 1 ?
There is no significant difference between the extinction rate of animals between 1950 and 2000 in China and the background extinction rate.
Figure 1 illustrates a process that occurs in a certain group of organisms. Which of the following best predicts the importance of this process?
This process is common to all members of Eukarya and allows noncoding regions of RNARNA to be removed so that proteins with the correct amino acid sequence are produced.
