According to the Darwinian concept of evolution, a giraffe has a long neck because:
1. | it was always like that since the beginning |
2. | during evolution the number of cervical vertebrae got increased |
3. | its ancestors stretched their necks to get food |
4. | ancestral giraffes with longer necks got more food and left more surviving offspring |
A population geneticist finds that a new allele in a population has suddenly increased in frequency. Most likely this allele is:
1. mutating rapidly
2. flowing with emigrants
3. strongly selected for
4. a product of assortative mating