Selective pressure Knowledge-Based Practice

Questions

1. 1.

   In evolutionary biology, which statement correctly distinguishes between biotic and abiotic selective pressures acting on a population?

   • A) Biotic selective pressures induce directed mutations in target organisms, whereas abiotic selective pressures eliminate only non-heritable variations.
   • B) Biotic selective pressures affect only mating displays and courtship, whereas abiotic selective pressures determine juvenile survival rates exclusively.
   • C) Biotic selective pressures stem from interactions with other living organisms, whereas abiotic selective pressures arise from non-living physical or chemical factors.
   • D) Biotic selective pressures operate solely on primary producers, whereas abiotic selective pressures act exclusively on higher-trophic-level consumers.
2. 2.

   Which statement accurately describes how an environmental selective pressure interacts with genetic variation during natural selection?

   • A) It acts as an external filter on existing phenotypic variation by conferring differential reproductive success rather than causing specific adaptations to arise.
   • B) It directly stimulates targeted genetic mutations in organisms that lack the traits necessary for survival under the new conditions.
   • C) It permanently eliminates all non-advantageous alleles from the gene pool within a single generation.
   • D) It increases the overall spontaneous mutation rate proportionally across the genome to generate novel adaptive phenotypes.
3. 3.

   Which condition must be met for an environmental factor to function as a selective pressure on a biological population?

   • A) The factor must cause differences in reproductive success that correlate with heritable phenotypic variation.
   • B) The factor must induce directed genetic mutations that allow organisms to cope with the challenge.
   • C) The factor must affect every individual in the population with equal severity regardless of phenotype.
   • D) The factor must cause immediate physiological adaptations that are permanently incorporated into the germline.
4. 4.

   Which statement best describes how a selective pressure influences the genetic composition of a population over generations?

   • A) It induces targeted genetic mutations that allow organisms to cope with new environmental conditions.
   • B) It alters allele frequencies by enabling individuals with advantageous traits to achieve higher reproductive success.
   • C) It maximizes overall genetic diversity by ensuring equivalent survival rates across all existing phenotypes.
   • D) It prompts individual organisms to permanently alter their physiological genotypes during their own lifetime.
5. 5.

   Which of the following scenarios directly describes the action of an environmental selective pressure on a biological population?

   • A) An indiscriminate drop in population size resulting from a sudden volcanic eruption
   • B) A spontaneous nucleotide substitution that produces no measurable change in organismal fitness
   • C) The random dispersal of individuals causing alleles to migrate into an adjacent population
   • D) A prolonged drought that selectively reduces the survival of shallow-rooted plants relative to deep-rooted variants

Answers and step-by-step solutions appear after you finish the test.