Consider two isolated populations of lady slipper orchids. these populations are hundreds of miles apart; one is in northern minnesota and the other is in the upper peninsula of michigan. they are so far apart that pollinators cannot possibly transfer pollen between the two populations. based on this information, you expect there to be between these two populations.

Over the past 60 years, many amphibian species have experienced significant population declines and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. in some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. if these resistant individuals continue to survive and prosper, new resistant populations might emerge. this would be an example of the founder effect artificial selection genetic drift natural selection sexual selection

Competition occurs between species when

Blood has traveled from the heart to the toes. which describes the next step of the circulation process?