Recessive alleles are necessarily more rare than dominant alleles. The molecular clock hypothesis is based on the assumptions that mutation rates are constant and natural selection is unimportant. The average number of individuals per square kilometer will probably not represent the actual density each individual experiences. The exponential growth curve is S-shaped. Five points each.
Polyploidy involves a multiplication of chromosome sets.
Thus polyploids may form a new species within the same geographic range as the diploid parental species. Heterozygote carriers of the sickle cell allele are resistant to malaria. Homozygotes with the normal allele are susceptible to malaria, an often fatal disease. Compare and contrast the views of selectionists and neutralists. Selectionists argue that natural selection maintains the genetic diversity found in most populations and that different alleles have different fitnesses associated with them.