1. explain what the ""biological species"" definition is. describe its strengths and weaknesses. 2. why does a biological species have to be reproductively isolated from other organisms? 3. compare allopatric and sympatric speciation. 4. briefly explain the following species barriers a. habitat isolation b. temporal isolation c. behavioral isolation d. mechanic isolation e. gametic isolation f. reduced hybrid viability g. reduced hybrid fertility h. hybrid breakdown 5. compare the concepts of gradualism and punctuated equilibrium.

There are six elements that make up most of the human body. which of the following is not one of these six elements?

The kind of fertilization found in the majority of aquatic animals is (internal or external) fertilization.

Humans are believed to have evolved in coastal regions in east africa. the region had an abundant supply of fish for early humanoids to eat. when scientists analyze the fads gene they see an interesting pattern. people whose families have lived in this area of east africa for generation show a high level of diversity in alleles for the fads gene. conversely, people whose families had migrated inland a moderate distance from sources of fish showed a much lower diversity for fads gene alleles. additionally, the fads alleles found in people whose family has lived inland for generation are almost all gene alleles which produce fads proteins with a high level of function and activity. how do anthropologists explain this?