CHAPTER 32 and 34 - ANIMAL ORIGINS AND Spring
VERTEBRATES 2011
Origins of Animal Diversity
1. List the characteristics and the hypothesized sequence of events in the origin of animals
from single-celled protists.
2. Describe the four derived traits that define the phylum Chordata.
3. Explain briefly the different genetic origins of genetic variation.
4. Explain the Hox gene and its evolutionary importance.
Craniates are Chordates with a Head
5. Discuss the importance of gene duplication in chordate evolution.
6. It turns out that, in several different animal lineages, organisms with heads first
appeared around 530 million years ago. Does this finding constitute proof that having a
head is favored by natural selection? Explain.
Vertebrates are Craniates with a Backbone
7. Describe a couple of important roles that mineralization may have played in early
vertebrates.
Gnathostomes are Vertebrates with Jaws
8. Describe three new evolutionary adaptations of gnathostomes.
Tetrapods are Gnathostomes with Limbs
9. Define and distinguish among gnathostomes, tetrapods, and amniotes. In particular,
explain why an amphibian is not considered an amniote.
Amniotes have Tetrapods with Amniotic Eggs
10. Describe reptile features that are adaptive for life on land.
11. Explain why non-bird reptiles should be called “ectothermic” rather than “coldblooded”.
Mammals are Amniotes with Hair and Milk
12. Distinguish among monotreme, marsupial, and eutherian mammals. Which type are
humans?
13. Describe the general characteristics of primates. Note in particular the features
associated with an arboreal existence.
Humans are Bipedal Mammals with Large Brains
14. Explain what analyses of mitochondrial DNA and Y chromosome suggest about human
origins and geographic migrations.