#Question id: 4997
#Unit 11. Evolution and Behavior
If one organ is an exaptation of another organ, then what must be true of these two organs?
#Question id: 4998
#Unit 11. Evolution and Behavior
Many species of snakes lay eggs, but in the forests of northern Minnesota where growing seasons are short, only live-bearing snake species are present. This trend toward species that perform live birth is an example of
#Question id: 4999
#Unit 11. Evolution and Behavior
In the 5—7 million years that the hominid lineage has been diverging from its common ancestor with the great apes, dozens of hominid species have arisen, often with several species coexisting in time and space. As recently as 30,000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both species had large brains and advanced intellects. The fact that these traits were common to both species is most easily explained by which of the following?
#Question id: 5000
#Unit 11. Evolution and Behavior
The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that
#Question id: 5001
#Unit 11. Evolution and Behavior
Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some of these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that
#Question id: 5002
#Unit 11. Evolution and Behavior
All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago.
The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on the information above, which explanation is most likely?