Q: A population of beetles has two alleles for a gene: A and a. If the frequency of allele A ($$p) is 0.7 $$and the frequency of allele a ($$q) is 0.3$$, what is the expected frequency of heterozygotes ($$2pq) $$under Hardy-Weinberg equilibrium?

$$2pq = 2 \times 0.7 \times 0.3 = 0.42$$

Question 1

Which of the following best describes a vestigial trait, and what does its presence in a species suggest about evolutionary processes?

Accepted Answer

A structure that is reduced or nonfunctional but similar to a functional structure in an ancestor, providing evidence for change through time.

Question 2

A population of beetles has two alleles for a gene: A and a. If the frequency of allele A ($$p) is 0.7 $$and the frequency of allele a ($$q) is 0.3$$, what is the expected frequency of heterozygotes ($$2pq) $$under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$$

Question 3

Which scenario best illustrates disruptive selection in a natural population?

Accepted Answer

A population of fish where both individuals with very high and very low numbers of gill rakers survive better than those with intermediate numbers.

Question 4

Which of the following is NOT an assumption of the Hardy-Weinberg equilibrium?

Accepted Answer

There is non-random mating based on phenotype.

Question 5

A small group of lizards is blown by a storm to a new island, where they establish a new population. Over time, the allele frequencies in this population differ from the original. This is an example of:

Accepted Answer

Founder effect, a type of genetic drift

Question 6

Which of the following best explains why gene flow tends to reduce genetic differences between populations?

Accepted Answer

Gene flow introduces new alleles into a population, making allele frequencies more similar across populations.

Question 7

Which of the following is a postzygotic reproductive isolating mechanism?

Accepted Answer

Hybrid sterility, where hybrid offspring mature but are sterile as adults.

Question 8

A botanist discovers a new plant species that arose when two different species hybridized and the offspring underwent chromosome doubling, resulting in a fertile plant with two full sets of chromosomes from each parent. This is an example of:

Accepted Answer

Allopolyploidy

Question 9

Which of the following statements about the fossil record is correct?

Accepted Answer

Organisms with hard parts and those living in sediment-rich environments are more likely to be fossilized.

Question 10

Which of the following is a key difference between Bacteria and Archaea?

Accepted Answer

Bacteria have peptidoglycan in their cell walls, while Archaea do not.

Question 11

A researcher is studying a bacterial infection and wants to determine if a specific microbe is the causative agent. According to Koch’s postulates, which step must be performed after isolating the suspected microbe in pure culture?

Accepted Answer

Inoculate a healthy, susceptible organism with the cultured microbe and observe if the same disease develops.

Question 12

Which of the following best describes the process of lateral (horizontal) gene transfer in prokaryotes?

Accepted Answer

Transfer of genetic material between unrelated species, often via plasmids or viruses.

Question 13

Which metabolic strategy is used by prokaryotes that obtain energy from inorganic molecules and carbon from CO$$_2$$?

Accepted Answer

Chemolithoautotrophy

Question 14

Which of the following is strong evidence supporting the endosymbiotic origin of mitochondria?

Accepted Answer

Mitochondria are similar in size to alpha-proteobacteria and have their own circular genome.

Question 15

Which of the following statements about alternation of generations in plants is correct?

Accepted Answer

Nonvascular land plants are gametophyte dominant, while seed plants are sporophyte dominant.

Question 16

Which of the following is a key innovation that allowed seed plants to colonize drier terrestrial environments?

Accepted Answer

Evolution of pollen grains, allowing sperm transfer without water.

Question 17

Which of the following is a defining feature of animals that distinguishes them from fungi?

Accepted Answer

Animals are multicellular heterotrophs that ingest their food before digesting it.

Question 18

Which of the following best describes the difference between protostomes and deuterostomes during embryonic development?

Accepted Answer

Protostomes develop the mouth before the anus; deuterostomes develop the anus before the mouth.

Question 19

Which of the following is a characteristic unique to chordates at some stage of their life cycle?

Accepted Answer

Presence of a dorsal hollow nerve cord.

Question 20

Which of the following statements about viruses is correct?

Accepted Answer

Viruses lack ribosomes and depend on host cells for protein synthesis.

Comprehensive Study Notes: Evolution, Speciation, History of Life, Prokaryotes, Protists, Plants, Animals, and Viruses

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