The A allele is dominant and beneficial compared to the A' allele. The A allele is recessive and beneficial compared to the A' allele. The A allele is dominant and harmful compared to the A' allele. The A allele is recessive and harmful compared to the A' allele. This figure shows the distribution of wing length in a population of dragonflies.
Natural selection acts directly on a. the phenotype.
The forelimbs of birds and bats are a. homologous b. analogous. The first step in speciation in animals is usually a. evolution of premating isolating mechanisms. Most biological diversity has probably arisen by a. anagenesis. In any population variation exists and much of this variation is heritable. Individuals with more favorable traits are more likely to reproduce and these inherited favorable traits become more common in succeeding generations.