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Zorluk: KolayModern Evolutionary Theory and Genetic Basis of Evolution

Arrange the following steps in the correct chronological sequence to illustrate how modern evolutionary theory (Neo-Darwinism) explains a change in allele frequency within a population.

  1. 1A random genetic mutation occurs in germline DNA, producing a novel allele.
  2. 2The new allele expresses a phenotypic trait that confers a selective advantage in the environment.
  3. 3Organisms possessing the advantageous trait experience greater survival and differential reproductive success.
  4. 4The frequency of the beneficial allele increases in the population's gene pool over successive generations.

Cevap

The correct chronological sequence begins with a random germline mutation introducing a new allele, followed by phenotypic expression of a beneficial trait, differential reproductive success of favored individuals, and finally an increase in allele frequency in the population's gene pool.
Modern evolutionary theory specifies that random gene mutations generate novel alleles, which express phenotypic traits. Environmental selective pressures favor individuals bearing advantageous phenotypes, leading to higher reproductive success. Consequently, the frequency of those advantageous alleles increases in the population's gene pool over time.

Adım Adım Çözüm

1
Identify the origin of new genetic variation in population genetics.
Random gene mutation in germline cells creates a new allele.
According to the modern synthesis, mutation is the ultimate primary source of novel genetic variation.
2
Determine how the new allele manifests in the organism.
The novel allele is expressed phenotypically and provides an adaptive advantage.
Natural selection operates on phenotypic variations produced by underlying genotypes.
3
Analyze the impact of the adaptive trait on reproduction.
Organisms with the trait survive better and leave more offspring (differential reproduction).
Advantageous traits improve fitness, enabling higher reproductive output.
4
Trace the population-level genetic outcome over generations.
The beneficial allele's frequency rises in the gene pool across generations.
Evolution at the microevolutionary scale is defined as a change in population allele frequencies over time.

Anahtar Kavram

Neo-Darwinian Mechanism of Evolution
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