What events would lead to directional selection?
_____ a new allele arises that increases fitness
_____ a population's main food source changes
_____ a population's environment becomes increasingly heterogenous
_____ heterozygotes have a fitness advantage over homozygotes
__X__ a new allele arises that increases fitness
__X__ a population's main food source changes
_____ a population's environment becomes increasingly heterogenous
_____ heterozygotes have a fitness advantage over homozygotes
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If a pedigree of several generations shows only females affected by a particular trait, it cannot be a(n) ____ trait
a. autosomal recessive b. autosomal dominant c. Y-linked d. X-linked recessive e. X-linked dominant
A small angle for a branch point in an evolutionary tree indicates
A. extinction. B. punctuated equilibrium. C. gradualism. D. convergent evolution. E. temporal isolation
Glyceraldehyde-3-phosphate can do all of the following except
A. be converted to usable energy for the cell. B. manufacture lipids. C. produce trace elements required for plant growth (nitrogen, magnesium, phosphorus, etc.). D. be converted to ribulose.
Answer the following questions true (T) or false (F)
1. Acute inflammation is normally beneficial. 2. The growth of some microbes is inhibited by elevated body temperature. 3. Neutrophils can kill bacteria by nonphagocytic mechanisms.