Biology questions ! ?
charles darwin's main focus was on the gradual process of adaptation within populations. this form of change a) explains all important forms of evolutionary change b) is the main means by which new species arise c) cannot account for increases in species diversity over time d) occurs mainly in small, isolated populations e) leads to the formation of major new branches on the tree of life often, the morphological species concept is used to define and describe species. why? a) if two organisms look alike, they must be the same biological species. b) the morphological species concept defines a species in terms of its reproductive behavior, which is the most direct way to identify biological species. c) if two organisms look different, they must be different biological species. d) this is the most convenient way of identifying species, and it is one of the few ways to identify fossil or asexual species. e) physical traits clearly define unique branches on the tree of life. the following options are all reproductive barriers. which one is an example of a prezygotic barrier in which the two different species do mate? a) one bird species lives in wetlands, the other in dry forests; hence, they do not encounter each other. b) hybrid mules produced by mating donkeys and horses are sterile. c) two dragonfly species regularly mate, but their gametes are incompatible. d) two crayfish species cannot interbreed because their genitalia do not engage properly with each other. e) two daisy species produce hybrid offspring, but the hybrids produce very few seeds. what is the first step in allopatric speciation? a) genetic drift b) geographic isolation c) polyploidy d) hybridization e) formation of a reproductive barrier according to the model, evolution occurs in spurts: species evolve relatively rapidly and then remain unchanged for long periods. a) allopatric b) gradualist c) adaptive radiation d) punctuated equilibrium e) mutation