Yellow birch (Betula cordifolia) and mountain birch (Betula alleghaniensis) have overlapping ranges. Pollen grains from one species are unable to germinate and make pollen tubes on female ovules of the other species. These two birch species are kept separate by _______.

List the five Hardy-Weinberg assumptions and give one sentence for each on how they could be violated.

Wheat plants have a gene for stalk length, with tall stalks dominant over short stalks. Wheat plants have a second gene for leaf texture, with rough texture dominant over smooth texture. You are given a plant with tall stalks and rough textured leaves. a. What type of wheat plant do you cross with your given plant to determine the genotype of the tall-stalked, rough-textured leaf plant? b. Assume that your given plant was heterozygous for stalk length and homozygous for leaf texture. What is the expected ratio of phenotypes in the offspring of your cross from the previous step?

In a large, sexually reproducing population, the frequency of an allele changes from 0.6 to 0.2. From this change, one can most logically assume that in this environment…

The four gametes produced from one completed meiotic event _________.

You are an undergraduate student working with a graduate student in an entomology lab, and she presents you with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to help her separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use?

In a population of plants, there are some pollinators that visit the tallest plants, a different species of pollinator that visits medium-height plants, and a third species of pollinator that prefers the shortest plants. If the pollinator that prefers medium-height plants goes extinct, what mode of selection will be acting on the plant population?

The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment means that…

Which organ system is not commonly affected by systemic scleroderma?

Which of the following is the energy storage found in our muscles?