Chapter 31, Problem 3
What two major lineages make up the living Amniota?
Video transcript
True or false? Both echinoderms and vertebrates have endoskeletons. Explain.
What trait(s) characterize the vertebrates? a. vertebrae and a cranium b. jaws and a spinal cord c. bony endoskeleton d. notochord and post-anal tail
Most species of hominins are known only from Africa. Which species have been found in other parts of the world as well?
a. early Homo—H. habilis and H. ergaster
b. H. erectus, H. neanderthalensis, and H. floresiensis
c. Australopithecus afarensis
Which statement is true about endothermy in mammals and birds? a. They both inherited this trait from a common ancestor. b. Birds are more closely related to mammals than to reptiles. c. Endothermy arose independently in these two lineages. d. Birds are reptiles and all reptiles are ectothermic.
To estimate the relative abundance of the major phyla, calculate how many named species of arthropods, mollusks, and nematode worms exist per named species of chordate (the phylum containing vertebrates, including humans; see Table 30.1). Do you think these calculations are likely to be underestimates or overestimates? Why?