evolution

In addition to the ABOABO blood groups, humans have an MNMN blood type system in which the MM and NN alleles are codominant to one another. A group of scientists found that in one population the frequency of the MM allele was 0.82, and the frequency of the NN allele was 0.18. If the population is in Hardy-Weinberg equilibrium, the frequency of heterozygotes is determined by the expression 2pq, where p is the frequency of one allele and q is the frequency of the other. Assuming that the population is in Hardy‑Weinberg equilibrium, which of the following is the expected frequency of individuals with the genotype MN a. 0.295 b. 0.640 c. 0.672 d. 0.148

a. 0.295

Whales, bony fishes, and cartilaginous fishes all have similar adaptations that enable them to live in the ocean. Figure 1 shows the phylogenetic relationships of selected vertebrates. Figure 1. Cladogram of selected vertebrate groups Based on the phylogenetic relationships shown in Figure 1, which of the following best explains the similarities exhibited by whales, bony fishes, and cartilaginous fishes? a. Convergent evolution, because these organisms do not share a recent common ancestor. b. Adaptive radiation, because all three groups evolved from a unique, shared common ancestor from the cartilaginous fishes group. c. Mutation, because the shared traits can be traced back to a shared recent common ancestor. d. Founder effect, because all three groups formerly existed together as one population that then was disrupted, causing speciation.

a. Convergent evolution, because these organisms do not share a recent common ancestor.

In a particular region, a species of lizard lives in the lowlands. Even though there are numerous mountains in the region, the climate on the mountains is too cold for the lizards to survive. Scientists are concerned that the lowlands will become much warmer by the end of the twenty-first century and will become unsuitable for this lowland lizard species. Which of the following best predicts the impact on the lizard species if there is a gradual increase in the average temperatures found in both the lowlands and mountains in this region? a. Some lizards will migrate to new habitats in the mountains and become isolated, leading to allopatric speciation. b. The species will undergo artificial selection, as the genes will adapt to warmer temperatures. c. The species will experience a genetic bottleneck, and sympatric speciation will result in the development of several new species. d. The lizards will hybridize with a different lizard species that is adapted to a warmer environment, leading to increased genetic variation in the species.

a. Some lizards will migrate to new habitats in the mountains and become isolated, leading to allopatric speciation.

A famous study from the nineteenth century involves the peppered moth, Biston betularia, commonly found in Great Britain and Ireland. At that time, the moths, normally white with black speckles, known as the peppered variety, became less common than the solid black variety. The population was predominantly black throughout the nineteenth century. By the end of the twentieth century, the peppered version of the moth was again more common than the black version. Which of the following best explains the phenotypic pattern in the moths over time? a. The frequencies of the different phenotypes in the moth population changed randomly due to genetic drift. b. The increased air pollution of the nineteenth century due to the use of coal led to a darkening of surfaces from soot. The darker backgrounds conferred a selective advantage to the black variety, as described by natural selection. A shift to less polluting fuel in the twentieth led to cleaner air and a lightening of the moth's normal habitat. c. During the nineteenth century, increased ship commerce between Great Britain and Ireland facilitated the gene flow of the black variety, spreading it throughout the moth's normal range. The switch to increased transport by planes during the twentieth century reduced this gene flow. d. The black variety was a nineteenth century mutation, dominant to the peppered variety. The allele for the peppered trait, being recessive, decreased in frequency. However, an additional mutation in the black allele changed it from a dominant to a recessive allele at the turn of the twentieth century, leading to a return to the dominance of the original peppered variety.

b. The increased air pollution of the nineteenth century due to the use of coal led to a darkening of surfaces from soot. The darker backgrounds conferred a selective advantage to the black variety, as described by natural selection. A shift to less polluting fuel in the twentieth led to cleaner air and a lightening of the moth's normal habitat.

To prevent the loss of genes as chromosome ends wear down during DNADNA replication, the tips of eukaryotic chromosomes have specialized DNADNA "caps" called telomeres. Telomeres consist of hundreds or thousands of repeats of the same short DNADNA sequence, which varies between organisms. The telomeric repeat sequences for selected organisms are given in Table 1. Which of the following best predicts why humans and mice have identical telomeric repeat sequences? a. Humans and mice have the same number of genes. b. Humans and mice have the same number of chromosomes. c. Humans and mice share a recent common ancestor that had the 5′-TTAGGG-3′ repeat sequence in its telomeres. d. Mice utilized the 5′-TTAGGG-3′ telomeric repeat sequence first, but the sequence independently evolved in humans as well.

c. Humans and mice share a recent common ancestor that had the 5′-TTAGGG-3′ repeat sequence in its telomeres.

Table 1 summarizes selected characteristics of organisms from each of the three domains of life. Table 1. A Summary of Selected Characters across Domains of Life Which of the following sets of data provides evidence that best supports common ancestry for organisms in all three domains? a. There are autotrophic and heterotrophic organisms found in Bacteria, Archaea, and Eukarya. b. There is a progression of pathways in organisms found in Bacteria, Archaea, and Eukarya. c. Organisms in Bacteria, Archaea, and Eukarya each have adenine, thymine, guanine, and cytosine bases forming their DNA. d. There is a progression of cellular organization in organisms found in Bacteria, Archaea, and Eukarya.

c. Organisms in Bacteria, Archaea, and Eukarya each have adenine, thymine, guanine, and cytosine bases forming their DNA .

Catalase is a protein enzyme that catalyzes the breakdown of hydrogen peroxide (H2O2)(H2O2) into water and oxygen gas in the cells of many living organisms. Students used an online database, which used the structure of catalase from different species, to generate the phylogenetic tree shown in Figure 1. Figure 1. Relationships of selected organisms based on catalase structure Which of the following student claims is best supported by the data provided? a. Mushrooms and potatoes are most closely related, since the node they share gave rise to all of the other organisms. b. Cattle are equally related to pigs and sheep, because the phylogeny places cattle between pigs and sheep. c. Yeast and mushrooms are the most closely related, because they are both fungi. d. Cattle and sheep are separated by only one node, and they are separated from the other organisms by more than one node.

d. Cattle and sheep are separated by only one node, and they are separated from the other organisms by more than one node.

Figure 1 shows some major structural changes between a typical prokaryotic cell, the first eukaryotic common ancestor, and the last eukaryotic common ancestor. Figure 1. Models of a prokaryote, first eukaryotic common ancestor, and last eukaryotic common ancestor. Based on the information provided in the figure, which of the following best describes how membrane-bound organelles provided unique evolutionary advantages to the last eukaryotic common ancestor? a. Cells with nuclear membranes were better able to protect their genetic material against damage. b. Cells with flagella were better able to find food and escape predators. c. Cells with ribosomes were better able to produce proteins needed for a variety of metabolic functions. d. Cells with mitochondria were able to utilize metabolic energy more efficiently.

d. Cells with mitochondria were able to utilize metabolic energy more efficiently.

There are two species of elephant seals: northern elephant seals, Mirounga angustirostris, found off the western coast of North America from Baja California to the Gulf of Alaska, and southern elephant seals, M. leonina, found in the southern oceans. Hunting in the nineteenth century has been blamed for a drastic reduction in the northern elephant seal population. Even though the population has rebounded following restrictions on seal hunting, genetic variation is greatly reduced in the northern species compared to that in the southern species. A small population typically shows decreased genetic variation, and if the population is reduced sufficiently, it will undergo a bottleneck, where some previously existing genetic variants will be lost, Which of the following conditions of Hardy-Weinberg equilibrium was most likely not met in the northern elephant seal population following overhunting? a. Absense of Selection b. No new mutations c. Random Mating d. Large Population Size

d. Large Population Size

Scientists want to determine the age of four fossil specimens. They have analyzed the fossils and gathered the data shown in Table 1. **amino acid differences of a conserved protein compared with a fifth fossil specimen Carbon-14 is incorporated into living organisms based on the percent of carbon−14 in the atmosphere. After the organism dies, carbon−14 breaks down by radioactive decay. Which of the specimens indicated in the table is the oldest? a. Specimen 1 b. Specimen 2 c. Specimen 3 d. Specimen 4

d. specimen 4