#Question id: 4647
#Section 2: Evolution
The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. Which of the five common ancestors, labeled V—Z, has been most successful in terms of the percent of its derived species that are extant?
#Question id: 4648
#Section 2: Evolution
In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely be observed in the algae-eater population over the course of many generations?
#Question id: 4649
#Section 2: Evolution
Which statement best describes the evolution of pesticide resistance in a population of insects?
#Question id: 4651
#Section 2: Evolution
Some members of a photosynthetic plant species are genetically resistant to an herbicide, while other members of the same species are not resistant to the herbicide. Which combination of events should cause the most effective replacement of the non-herbicide-resistant strain of plants by the resistant strain?
1. The presence of the herbicide in the environment
2. The absence of the herbicide from the environment
3. The maintenance of the proper conditions for one generation
4. The maintenance of the proper conditions for many generations
#Question id: 4655
#Section 2: Evolution
Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?
#Question id: 4656
#Section 2: Evolution
Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?