Eight Different Classes of Vertebrates Help (page 4)

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Updated on Aug 29, 2011

Order Proboscidea

An elephant, of course, has a very long nose or proboscis (proh- BAHS -is) – an “elephant’s trunk or means of providing food.” Elephants, therefore, belong to the Order Proboscidea ( pro -bah- SID -ee-uh), because of their long, tube-like proboscis (trunk) they use for gathering leaves and other food.

Order Sirenia

Fairly closely related to the trunked Proboscidea are the members of the Order Sirenia ( sigh - REE -nee-ah) – consisting of the sirens ( SIGH -rens) or “sea nymphs.” According to ancient Greek and Latin mythology, the sirens or sea nymphs (later called mermaids) were half woman and half fish creatures of the sea who lured sailors to their deaths on rocky shores by seducing them with their bewitching singing! In modern times, the seductive “sea nymphs” are now known as the manatees ( man -uh- TEES ). But one look at the manatee, also called the sea cow, will reveal a big, chubby, torpedo-shaped body with fin-like forelimbs, and no hindlimbs. The manatees are sea cows in much the same sense as the land-dwelling cows busily munching in farmer’s fields; they are aquatic (uh- KWAT -ik) or “water ( aqua )-dwelling” creatures that are herbivores ( HER -buh-vors), “devourers” ( vor ) of “herbs or plants” ( herbi ).

Real cows, of course, have milk-giving udders. And the plant-eating manatee herbivores are named for their “female breasts” ( manati ). According to the World Book Dictionary , “The manatee . . . by its quiet breathing and gentle breasts probably originated the haunting mermaid legends.”

Order Carnivora

Starkly opposite to the herbivores in their feeding habits are the members of the Order Carnivora (car- NIV -er-uh). The carnivores ( CAR -nih-vors) are the “flesh-eaters.” These flesh-eaters have specialization of their teeth for gripping and tearing. The large, sharp canines ( KAY -nines) of dogs, wolves, and foxes, for example, help tear meat apart when eating it.

Order Cetacea

The Order Cetacea (suh- TAY -shuh) consists of the “large sea animals,” such as the dolphins, porpoises, and whales. These cetaceans (suh- TAY -shuns) are actually a group of marine mammals that have sleek, fish-like bodies. They sport paddle-shaped forelimbs, but no hindlimbs. Even though they may casually resemble fish, they are homeothermic (endothermic) like other mammals, and nurse their young with milk.

Order Primates

Finally, we come to our own group, the Order Primates. The primates were briefly introduced back in Chapter 3. Recall that they are considered “of first rank or importance” ( primat ). Why? Naturally, because they include us, Homo sapiens ! We members of Homo sapiens are classified as omnivores ( AHM -nuh-vors). Translated into Common English, that means we are “greedy eaters” ( vores ) of almost “everything” ( omni )! Hence, in contrast to those mammalian Orders that only include herbivores, and those that only contain carnivores, members of Homo sapiens have the great advantage of being very flexible in their diet. Perhaps this flexibility in diet, combined with great manual ( MAN -yew-al) dexterity (deck- STAIR -uh-tee) – skillful use of the “right” ( dextr ) and left “hands” ( manu ) – has allowed our species to use its superior intelligence to prevail. As a result, members of Homo sapiens have put all of the other mammals into zoos (not allowing all of the other mammals to put us into the zoos)!

Figure 12.8 provides an extensive summary diagram of the three major groups and all of the important Orders of the mammals.

The Chordata: Animals with a “Chord” in Their “Back” Wide Diversity in Backboned Creatures: Eight Different Classes of Vertebrates The Three Major Groups Of Mammals

Fig. 12.8 The great story of the mammals.

Study suggestion: After each technical term and mini-picture in the diagram, see if you can remember the literal English translation. These translations help tell “The Great Story of the Mammals.” Note the groups of mammals that are most closely related, indicated by their encircling within a dotted line. Look back over the last few pages of the book to check your answers.


Practice problems for these concepts can be found at: Chordata Practice Test

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