Examkin

Soru

Zorluk: Çok zorEvolution and Adaptation

In a population of cave-dwelling fish, the allele for functional eyes (EE) is completely dominant over the allele for blindness (ee). The original surface-dwelling ancestors of these fish possessed fully functional eyes. However, after millions of years of isolation in completely dark subterranean caves, the entire fish population is now blind. Which of the following statements best explains the evolutionary mechanism that led to this outcome?

  1. The metabolic energy conserved by not developing unnecessary eye tissues provided a selective advantage to individuals expressing the recessive blindness phenotype, increasing their reproductive success.Cevap
  2. B
    Because they were in complete darkness, individual fish gradually lost their vision over their lifespans from lack of use, and this acquired blindness was inherited by subsequent generations.
  3. C
    Since the functional eye allele is dominant, it would naturally remain the most frequent trait in the population; therefore, the current population must have descended from a completely different, originally blind species.
  4. D
    The complete absence of light directly caused the dominant functional eye alleles within individual fish to intentionally mutate into the recessive blindness alleles to ensure the population's survival.

Cevap

The metabolic energy conserved by not developing unnecessary eye tissues provided a selective advantage to individuals expressing the recessive blindness phenotype, increasing their reproductive success.
Natural selection favors traits that improve reproductive success. Even though blindness is a recessive trait, the metabolic energy saved by not developing useless eye tissue in a completely dark environment provided a significant survival advantage, allowing blind individuals to out-reproduce fish with functional eyes.

Adım Adım Çözüm

1
Analyze the environmental pressure on the population.
The environment is completely dark, making functional eyes useless and their development a waste of metabolic energy.
Identifying the selective pressure is the first step in determining how natural selection will affect allele frequencies.
2
Relate the genetic traits to the environmental pressure.
Individuals with the recessive alleles (eee e) saved metabolic energy by not developing eyes, giving them a survival advantage over those with the dominant allele (EE).
Traits only provide an advantage or disadvantage in the context of their specific environment.
3
Apply the principles of natural selection.
Over generations, the blind individuals survived longer and reproduced more successfully, causing the recessive blindness allele to become fixed in the population despite being genetically recessive.
Natural selection is driven by reproductive success, which ultimately changes the genetic makeup of the population over time.

Anahtar Kavram

Natural Selection and Evolutionary Trade-offs
Tahmini Süre:1m 30s
Bu soruyu puanla

Konular

Evolution and Adaptation

Bu konudan daha fazla soru