You will use information on the World Wide Web
to answer a series of questions.

EXERCISE 1
CONVERGENT EVOLUTION AND MAMMAL DIVERSITY

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Convergent evolution has produced mammals on different continents that look similar and occupy similar niches, but are not closely related. Some of these similar-looking mammals were once grouped together. Closer examination of skeletal structures, as well as protein and DNA analysis, has led to better classification schemes. You will be using the Animal Diversity Web from the University of Michigan to answer the following questions about mammal classification and to investigate a mammal of your choosing.

Print out the worksheet below and use the link above to answer the following questions.

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Name _____________________________________________________

 

Link and Think: Convergent Evolution and Mammal Diversity

Use the Animal Diversity Web to get descriptions of mammalian orders and profiles of specific species. You may access this information by conducting a quick search, or by browsing the mammal pages.

1. The pangolin, or scaly anteater, was once grouped with the armadillos and anteaters. It has now been reclassified in a new order called Pholidota. What order do the armadillo and anteater belong to? What other animal belongs to this order (it comes in two or three-toed varieties)?

2. To understand the old and revised classification of the pangolin, write "yes" or "no" in the table below. The last column is for the animal that you named in question 1. You should also write in the geographical region in which these animals are found (Africa, Asia, Americas) in the last row. If you would like to take a look at the pangolin, see the Pholidota Page from the University of California Museum of Paleontology.

	Pangolin	Anteater	Armadillo	Two- and three-toed _____
Any teeth?		no
Body armor?				v
Claws?
Long tongue?			no	no
Eats insects?
Xenarthrous processes on lumbar vertebrae?
Geographical distribution?

3. Have you ever seen an aardvark? Find the aardvark on the Animal Diversity Web and answer the following questions.

What similarities does the aardvark have to the pangolin and the anteater?

What order does it belong to?

4. You are given the job of identifying a mammal skull. It has no canine teeth. As you observe the skull, you see only two upper incisors, one on the right and one on the left. Closer inspection of the inside of the mouth, however, reveals two small, peg-like incisors directly behind the larger teeth. You also notice that the back and front of the incisors are covered with enamel. Look at the Animal Diversity Web to find out the dental characteristics of rodents, hyraxes, and lagomorphs, then read about the Kinds of Teeth to find out how to interpret a "dental formula." Your textbook also has a diagram of mammal teeth on page 649. What type of mammal does the skull belong to? Justify your answer.

rodent

hyrax

lagomorph

 

Reason:

 

5. Take a look at this photo of a hyrax, then read the description of the hyrax on the Animal Diversity Web. Circle the two mammals that have been closely linked to the hyrax.

elephants	rabbits	sirenians
walrus	rodents	bats

 

6. Investigate a mammal of your choosing on the Internet, preferably one your classmates have probably never heard of. You should start with the Animal Diversity Web, but will probably have to use HotBot, or another search engine, to find a photo of your mammal. (If you use HotBot, make sure to check the "image" box iand be specific!) Suggested mammals include: bandicoot, aye-aye, quagga, siamang, capybara, marmot, serval, pika, sugar glider, bonobo, aardwolf, hyaena, colugo, tenrec, bettong. Suggested categories of mammals: smallest mammal, poisonous mammals, mammals with unusual forms of hair.

Other possible resources:

• Mammal Species of the World (MSW): Search this database using common or scientific names to identify the classification of mammal species. Click 'parent' to move to higher taxa; click 'offspring' to move to lower taxa.
• IUCN Red List of Threatened Animals: Search this database for a specific species to find out if it is considered threatened or endangered.

Name:
Scientific name:
Order:
Physical description (attach photo):
Oddest characteristic:
Food:
Geographic region:
Extinct, endangered, or threatened?