Imagine that you are a marine biologist. As part of your exploration, you dredge up an

Bilateral symmetry in the animal kingdom is best correlated with a. an ability to sense equally in all directions. b. the presence of a skeleton. c. motility and active predation and escape. d. development of a body cavity

Identify which of the following categories includes all others in the list: arthropod, arachnid, insect, butterfly, crustacean, millipede.

The oldest group of tetrapods is the __________.

Reptiles are much more extensively adapted to life on land than amphibians because reptiles a. have a complete digestive tract. b. lay eggs that are enclosed in shells. c. are endothermic. d. go through a larval stage

What is the name of the phylum to which humans belong? For what anatomical structure is the phylum named? Where in your body is a derivative of this anatomical structure found?

Fossils suggest that the first major trait distinguishing human primates from other primates was __________.

Which of the following types of animals is not included in the human ancestry? (Hint: See Figure 17.30.) a. a bird b. a bony fish c. an amphibian d. a primate

Put the following list of species in order, from the oldest to the most recent: Homo erectus, Australopithecus species, Homo habilis, Homo sapiens.

Match each of the following animals to its phylum: a. human b. leech c. sea star d. lobster e. sea anemone 1. Echinodermata 2. Arthropoda 3. Cnidaria 4. Chordata 5. Annelida

Imagine that you are a marine biologist. As part of your exploration, you dredge up an unknown animal from the seafloor. Describe some of the characteristics you should look at to determine the phylum to which the creature should be assigned.

Vegan and vegetarian diets are increasingly popular. While vegans consume no animals or animal products, many vegetarians are less strict. Talk to acquaintances who describe themselves as vegetarians, or who follow a meat-free diet, and determine which taxonomic groups they avoid eating (see Figures 17.6 and 17.30). Try to generalize about their diet. What do they consider meat? For example, do they avoid eating vertebrates but eat some invertebrates? Do they avoid only birds and mammals? What about fish? Do they eat dairy products or eggs?

What adaptations inherited from our primate ancestors enable humans to make and use tools?

Interpreting Data Average brain size, relative to body mass, gives a rough indication of the intelligence of a species. Graph the data below for hominins. Which species is most similar to Homo floresiensis? Does this information support the hypothesis that Homo floresiensis is a dwarf form of Homo erectus or an alternative explanation? Hominin Species Mean Brain Volume (cm3 ) Mean Body Mass (kg) Australopithecus afarensis 440 37 Homo erectus 940 58 Homo floresiensis 420 32 Homo habilis 610 34 Homo neanderthalensis 1480 65 Homo sapiens 1330 64 Paranthropus boisei 490 41

This chapter presents a scientific understanding of human origins. Science is one approach to understanding the natural world (as you learned in Chapter 1). Reread the Biology and Society section and underline words or phrases that reflect a scientific approach to the study of Homo floresiensis. You are probably also familiar with at least one way of understanding human origins that is outside the scope of science. How does that approach to understanding life differ from a scientific one? What might be the potential value of studying human evolution in a scientific context?

Coral reefs harbor a greater diversity of animals than any other environment in the sea. Australias Great Barrier Reef has been protected as a marine reserve and is a mecca for scientists and nature enthusiasts. Elsewhere, such as in Indonesia and the Philippines, coral reefs are in danger. Many reefs have been depleted of fish, and runoff from the shore has covered coral with sediment. Nearly all the changes in the reefs can be traced back to human activities. What kinds of activities do you think might be contributing to the decline of the reefs? What are some reasons to be concerned about this decline? Do you think the situation is likely to improve or worsen in the future? Why? What might the local people do to halt the decline? Should the more industrialized countries help? Why or why not?

The human body has not changed much in the last 100,000 years, but human culture has changed a great deal. As a result of our culture, we change the environment at a rate far greater than the rate at which many species, including our own, can evolve. What evidence of rapid environmental change do you see around you? What aspects of human culture are responsible for these changes? Do you see any evidence of a decrease in the rate of human-caused environmental changes?