1. Animal Diversity II: Vertebrates
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2. Chordate features in the human embryo (F23.1 p. 450)
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3. Key Features of Chordates eye heart liver tail limb bud (future leg)
Figure: 23-1
Title:
Chordate features in the human embryo
Caption:
This 5-week-old human embryo is about 1 centimeter long and clearly shows a tail and external gill slits (more properly called grooves, since they do not penetrate the body wall). Although the tail will disappear completely, the gill grooves contribute to the formation of the lower jaw.
gill slit
limb bud (future arm)

4. Key Features of Chordates
Invertebrate Chordates Lack a Backbone
Invertebrate chordates (F23.2 p. 451)
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5. nerve cord notochord gut muscle segments tail (a) Lancelet mouth anus
gill slits
water enters
(mouth)
water exits
(b) Tunicate
atrial
opening
tail
mouth
anus
gill slits
Figure: 23-2
Title:
Invertebrate chordates
Caption:
(a) A lancelet, a fishlike invertebrate chordate. The adult organism exhibits all the diagnostic features of chordates. (b) The sea squirt larva (left) also exhibits all the chordate features. The adult sea squirt (a type of tunicate, middle) has lost its tail and notochord and has assumed a sedentary life, as shown in the photo (right).
nerve
cord
attachment
points
gut
gill
slits
notochord
larva
heart
gut
gonad
adult

6. Key Features of Chordates
Vertebrates Have a Backbone
Major Groups of Vertebrates
Some Vertebrates Lack Jaws
Hagfishes Are Slimy Residents of the Ocean Floor
Jawless fishes (F23.3 p. 452)
Some Lampreys Parasitize Fish
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7. Figure: 23-3
Title:
Jawless fishes
Caption:
(a) Hagfishes live in communal burrows in mud, feeding on worms. (b) Some lampreys are parasitic, attaching to fish (such as this carp) with suckerlike mouths lined with rasping teeth (inset).

8. Major Groups of Vertebrates
Jawed Fishes Rule Earth’s Waters
Cartilaginous Fishes Are Marine Predators
Cartilaginous fishes (F23.4 p. 453)
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9. Figure: 23-4
Title:
Cartilaginous fishes
Caption:
(a) A sand tiger shark displaying several rows of teeth. As outer teeth are lost, they are replaced by the new ones behind them. Both sharks and rays lack a swim bladder and tend to sink toward the bottom when they stop swimming. (b) The tropical blue-spotted sting ray swims by graceful undulations of lateral extensions of the body.

10. Major Groups of Vertebrates
Bony Fishes Are the Most Diverse Vertebrates
The diversity of the bony fishes (F23.5 p. 453)
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11. Figure: 23-5
Title:
The diversity of the bony fishes
Caption:
Bony fishes have colonized nearly every aquatic habitat. (a) This female deep-sea angler fish attracts prey with a living lure that projects just above her mouth. The fish is ghostly white; at the 6000 foot depth where anglers live, no light penetrates and thus colors are unnecessary. Male deep-sea angler fish are extremely small and remain attached to the female as permanent parasites, always available to fertilize her eggs. Two parasitic males can be seen attached to this female. (b) This tropical green moray eel lives in rocky crevices. A small fish (a banded cleaner goby) on its lower jaw eats parasites that cling to the moray's skin. (c) The tropical seahorse may anchor itself with its prehensile tail (adapted for grasping) while feeding on small crustaceans. Question In terms of water regulation (maintaining the proper amount of water in the body), how does the challenge faced by a freshwater fish differ from that faced by a saltwater fish?

12. Major Groups of Vertebrates
Amphibians Live A Double Life
Amphibian means “double life” (F 23.6 p. 455)
Copyright © 2005 Pearson Prentice Hall, Inc.

13. Figure: 23-6
Title:
Amphibian means "double life"
Caption:
The double life of amphibians is illustrated by the bullfrog's transition from (a) a completely aquatic larval tadpole to (b) an adult leading a semiterrestrial life. (c) The red salamander is restricted to moist habitats in the eastern United States. Salamanders hatch in a form that closely resembles the adult. Question What advantages might amphibians gain from their "double life"?

14. Major Groups of Vertebrates
Reptiles and Birds Are Adapted for Life on Land
The diversity of reptiles (F23.7 p. 456)
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15. Figure: 23-7
Title:
The diversity of reptiles
Caption:
(a) The mountain king snake has a color pattern very similar to that of the poisonous coral snake, which potential predators avoid. This mimicry helps the harmless king snake elude predation. (b) The outward appearance of the American alligator, found in swampy areas of the South, is almost identical to that of 150-million-year-old fossil alligators. (c) The tortoises of the Galapagos Islands, Ecuador, may live to be more than 100 years old.

16. Major Groups of Vertebrates
Have Scales and Shelled Eggs
The amniote egg (F23.8 p. 456)
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17. Figure: 23-8
Title:
The amniote egg
Caption:
An anole lizard struggles free of its egg. The amniote egg encapsulates the developing embryo in a liquid-filled membrane (the amnion), ensuring that development occurs in a watery environment, even if the egg is far from water.

18. Major Groups of Vertebrates
Birds Are Feathered Reptiles
The diversity of birds (F23.9 p. 457)
Archaeopteryx, the “missing link” between reptiles and birds (F23.10 p. 457)
Copyright © 2005 Pearson Prentice Hall, Inc.

19. Figure: 23-9
Title:
The diversity of birds
Caption:
(a) The delicate hummingbird beats its wings about 60 times per second and weighs about 0.15 ounce (4 grams). (b) This young frigate bird, a fish-eater from the Galapagos Islands, has nearly outgrown its nest. (c) The ostrich is the largest of all birds, weighing more than 300 pounds (136 kilograms); its eggs weigh more than 3 pounds (1500 grams). Question Although the ancestor of all birds could fly, many bird species, like the ostrich, cannot. Why do you suppose flightlessness has evolved repeatedly among birds?

20. Figure: 23-10
Title:
Archaeopteryx, the “missing link” between reptiles and birds
Caption:
The earliest known bird is Archaeopteryx, preserved here in 150-million-year-old limestone. Feathers, a feature unique to birds, are clearly visible, but the reptilian ancestry of birds is also apparent: like a modern reptile (but unlike a modern bird), Archaeopteryx had teeth, a tail, and claws.

21. Major Groups of Vertebrates
Mammals Provide Milk to Their Offspring
The diversity of mammals (F23.11 p. 458)
Nonplacental mammals (F p. 459)
Copyright © 2005 Pearson Prentice Hall, Inc.

22. Figure: 23-11
Title:
The diversity of mammals
Caption:
(a) A humpback whale gives its offspring a boost. (b) A bat, the only type of mammal capable of true flight, navigates at night by using a kind of sonar. Large ears help the animal detect echoes as its high-pitched cries bounce off nearby objects. (c) Mammals are named after the mammary glands with which females nurse their young, as illustrated by this mother cheetah. (d) The male orangutan can reach 75 kilograms (165 pounds). These gentle, intelligent apes occupy swamp forests in limited areas of the Tropics, but are endangered by hunting and habitat destruction.

23. Figure: 23-12
Title:
Nonplacental mammals
Caption:
(a) Monotremes, such as this platypus from Australia, lay leathery eggs resembling those of reptiles. The newly hatched young obtain milk from slitlike openings in the mother's abdomen. (b) Marsupials, such as the wallaby, give birth to extremely immature young who immediately grasp a nipple and develop within the mother's protective pouch (inset).

24. Figure: E23-1 Title: Amphibians in danger Caption: The corroboree toad, shown here with its eggs, is rapidly declining in its native Australia. Tadpoles are developing within the eggs. The thin water-permeable and gas-permeable skin of the adult and the jellylike coating around the eggs make them vulnerable to both air and water pollutants.