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Genetics and Evolution Flashcards

7 cards from real OAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. Which of the following describes allopatric speciation?

    Answer: A population divides into two species due to physical geographic barriers

    Allopatric speciation occurs when a geographic barrier physically separates a population into two isolated groups that diverge genetically until they can no longer interbreed.

  2. A deletion of one nucleotide in the middle of a coding sequence would most likely cause which type of mutation?

    Answer: Frameshift mutation altering all downstream codons

    Deleting a single nucleotide shifts the reading frame for all codons downstream, typically resulting in a completely different and usually non-functional protein.

  3. Which of the following is NOT a condition required to maintain Hardy-Weinberg equilibrium?

    Answer: Small population size

    Hardy-Weinberg equilibrium requires a large (ideally infinite) population; small population size promotes genetic drift, which is an evolutionary force that disrupts equilibrium.

  4. In a dihybrid cross between two AaBb parents, what is the expected ratio of offspring showing both dominant phenotypes (A_B_)?

    Answer: 9/16

    In a dihybrid cross (AaBb × AaBb) with independent assortment, 9 of 16 offspring are expected to show both dominant phenotypes (A_B_), giving a 9:3:3:1 ratio.

  5. Mitochondrial DNA is primarily inherited from:

    Answer: The mother only

    Mitochondria are inherited maternally because the egg contributes almost all the cytoplasm to the zygote, while sperm contribute little to no cytoplasm.

  6. Which of the following best describes convergent evolution?

    Answer: Unrelated species independently evolving similar traits due to similar environmental pressures

    Convergent evolution occurs when unrelated lineages independently evolve similar structures or traits in response to analogous selective pressures in their environments.

  7. A diploid organism has 2n = 8 chromosomes. How many chromosomes would be present in each daughter cell following meiosis II?

    Answer: 4

    Starting with 2n = 8, meiosis I reduces to n = 4 chromosomes per cell; meiosis II separates sister chromatids, yielding 4 chromosomes in each of the four resulting haploid cells.