Evolution by natural selection has been interpreted as “the strongest survive.” This is false; the strongest individuals in a population don’t always survive.  Why not? So, what is evolution by natural selection?

With respect to this form of natural selection, explain the meaning of the word directional.

Origins of Modern Humans Current data suggest that modern humans evolved from archaic humans primarily in East Africa. A 195,000 year old fossil from the Omo 1 site in Ethiopia shows the beginnings of the skull changes that we associate with modern people, including a rounded skull case and possibly a projecting chin. A 160,000 year old skull from the Herto site in the Middle Awash area of Ethiopia also seems to be at the early stages of this transition. It had the rounded skull case but retained the large brow ridges of archaic humans. Somewhat more advanced transitional forms have been found at Laetoli in Tanzania dating to about 120,000 years ago. By 115,000 years ago, early modern humans had expanded their range to South Africa and into Southwest Asia (Israel) shortly after 100,000 years ago. There is no reliable evidence of modern humans elsewhere in the Old World until 60,000-40,000 years ago, during a short temperate period in the midst of the last ice age.

A hypothetical population has two alleles for a “B" gene: B1 and B2. In a random sample of 50 diploid zygotes (for a total of 100 alleles), the following genotypes were found: 20 B1B1, 20 B1B2, and 10 B2B2 The above values represent the initial genotype frequencies of zygotes in the population. Let's say that selection acts against the B2 allele, and all 10 individuals with B2B2 genotype die off before reaching maturity (leaving 0 B2B2 individuals). (The number of surviving adults in the population is 40, so the number of alleles is 80). What is the new observed frequency of the homozygous dominant genotype? O A. 0.10 О В. О.70 O C. 0.25 O D.0.50 O E. 0.75

From the same fishing village in Alaska, where the allele frequency of webbed feet is 0.15, selection seems like a drastic step to increase the number of webbed footed individuals. Instead, the village examines how inbreeding would affect the population. If first cousins were allowed to mate, how frequently would webbed footed individuals be observed? (Remember this is a dominant trait!)