Subphylum Vertebrata

1. Subphylum Vertebrata Chapters 31, 32, 33 and 36

2. Evolution of the Vertebrates The Vertebrate Family Tree, the phylogenetic tree in fig. 36-2 on page 786, is just one hypothesis about how vertebrates are related.

3. Where Do We Start From? • Phylum Chordata: What is a Chordate? (page 645, Textbook) • Chordates are animals that are characterized by a notochord, a hollow dorsal nerve cord and pharyngeal (throat) slits. • Characteristics of Chordates: • Notochord • Hollow Dorsal Nerve Cord • Pharyngeal slits

4. Chordates Continued • Notochordis a long flexible supporting rod that runs through at least part of the body, usually along the dorsal surface just beneath the nerve cord. • Most chordates have a notochord only during the early part of embryonic life. • The hollow dorsal nerve cord runs along the dorsal surface just above the notochord. • In most chordates, the front end of this nerve cord develops into a large brain.

5. Fishes Chapter 31.1

6. What is a Fish? • Fishes can be defined as aquatic vertebrates that are characterized by scales, fins, and pharyngeal slits. • Living Fishes Fall into Three Main groups: • Jawless Fishes • Bony Fishes • Cartilaginous Fishes

7. Evolution of Fishes (page 681, Fig. 31.3)

8. Form and Function in FishesFeeding: • Fishes can be herbivores, carnivores, parasites, filter feeders, and detritus feeders. One fish can be one or more of the above at the same time. • Fish have many different adaptations for feeding. • Most either tear their food into conveniently sized chunks or swallow their prey whole. • The food is processed in the digestive system of the fish. An important part of the digestive system of some fishes is the pyloric ceca, which is located at the point where the stomach and the intestine meet.

9. A Fish!!!

10. Whale Shark

11. Form and Function Continued: Respiration: Internal Transport: Fishes typically have a closed circulatory system with TWO Chambered Heart. The heart consists of an atrium and a ventricle. The aorta carries the blood to the gills, where gas exchange occurs. • Most fishes breathe with gills that are located on either side of the pharynx. • Many fishes have different adaptations, which are the result of the many evolutionary processes.

12. Siamese Fighting Fish

13. Form and Function ContinuedResponse: • Well-organized nervous system with a brain. • Most fishes have well developed eyes with colour vision. • Fishes have ears, but have poor hearing. • Fishes also have a well-developed lateral line system, which helps them detect other fishes and prey. • The most anterior parts of a fish’s brain are the olfactory bulbs, which are connected to the cerebrum and involved in the sense of smell.

14. Fish Brain

15. Excretion: • The waste that fishes get rid of is ammonia(nitrogen-containing). • Some of the waste diffuses through the gills. • Some of the waste is removed by the kidneys.

16. Form and Function Continued:Reproduction: • Most fishes have separate sexes. • Many fishes are oviparous, which means they lay eggs. Most oviparous fishes have external fertilization. • Some fishes are ovoviviparous and youngs develop in an egg and feed off the egg’s yolk during development. • Some fishes are viviparous, or truly live-bearing.

17. Mating Cuttle Fish

18. Types of Fishes:Jawless Fishes (page 687, Textbook) • Lampreys (fig. 31-12, top) – they are typically filter feeders as larvae and parasites as adults. They attach to fishes (occasionally whales and porpoises) and scrape away at the skin with their large teeth and strong, rasping tongue. • Hagfishes (fig. 31-12, bottom) – most primitive vertebrates that are still living. They secrete incredible amounts of slime, have six hearts, possess an open circulatory system, and regularly tie themselves into half-knots.

19. Sharks and Their RelativesClass Chondrichthyes (page 688-89) • The class includes sharks, rays, skates, sawfish and chimaeras. • Most of the species have curved tails, torpedo-shaped bodies, and rounded snouts with a mouth underneath. • Not all sharks are carnivorous predators. Some are filter feeders and some have flat teeth used to crush the shells of mollusks and crustaceans. • Rays and skates are flattened sharks that live at the bottom of the ocean and move by flapping their large pectoral fins.

20. Bony FishesClass Osteichthyes (pages 689-90) • Oste- means bone • Almost all bony fishes belong to the enormous group called the ray-finned fishes. The group includes everything from guppies to groupers, salmon, and eels. • Only lungfishes and coelacanth fishes do not belong to the group of ray-finned fishes. • Lungfishes are found in Australia, Africa and South America. • Coelacanth fishes are found in Africa as well. They live in waters of 70 to 400 meters deep.

21. Amphibians Chapter 31.2

22. What is an Amphibian? Amphibians: Evolution of Amphibians: Most probably amphibians evolved from lobe-finned fishes. Let’s take a look at the phylogenetic tree in chapter 36. • Amphi- means both and bio- means life. • Amphibians can be defined as vertebrates that are aquatic as larvae and terrestrial as adults, breath with gills as adults, have a moist skin that contains many glands, and lack scales and claws.

23. Form and Function of Amphibians: Feeding: Respiration: Most adult amphibians breathe using lungs, mouth cavities, and skin. For example, frogs fill their mouth cavity with air, which is then forced into an opening called glottis and then into the lungs. • Tadpoles are typically filter feeders or herbivores, while adult amphibians are almost entirely carnivores.

24. Internal Transport: • The adult amphibian heart has three separate chambers: left atrium, right atrium and a ventricle. Adult amphibians have a double-loop, closed circulatory system. • The heart of a tadpole has only TWO chambers and a single loop system.

25. Amphibians! Excretion: Response: Amphibians have well-developed eyes that often bulge out of the sockets. They also have sensitive ears. Amphibians also have different, very ingenious ways of protecting themselves against predators. • Amphibians excrete urine with the help of kidneys.

26. Reproduction Some amphibians are oviparous with external fertilization. However, many have internal fertilization and are either oviparous, ovoviviparous, or viviparous.

27. Reptiles Chapter 32.1

28. What is a Reptile? • Reptiles are vertebrate animals that have lungs, a scaly skin, and a special type of egg – adaptations that enable them to live their entire life out of water. • Reptiles have an amniotic egg, which has protective layers and does not need water to survive.

29. Form and Function of Reptiles: Feeding: Respiration: Reptiles have two well-developed lungs. Some crocodiles have flaps of skin that can separate the mouth from the nasal passages, thus allowing them to breathe through their nostrils while their mouth is open. • Some reptiles, such as the iguana, are herbivores. • Some reptiles, such as snakes, are carnivores. • Reptiles have many adaptations for capturing and killing their prey.

30. Reptiles! Internal Transport: Excretion: Reptiles excrete urine, which is produced by kidneys. Some reptiles have a urinary bladder, which is used to store urine. Many reptiles excrete uric acid which is less toxic than ammonia. This helps with preventing excessive water loss. • Reptiles have a well-developed double loop circulatory system. • A reptile’s heart consists of two atria and one or two ventricles. • The dry skin of reptiles makes it necessary for them to have a well developed system of oxygen delivery.

31. Response: Sensory organs in reptiles are very well-developed with some exceptions. Snakes have a very good sense of smell but cannot hear. Snakes pick up smells with the help of their tongue. Some reptiles, such as vipers can detect heat, which helps them with catching prey.

32. Reptiles! Movement: Reproduction: All reptiles reproduce through internal fertilization. Almost all male reptiles have a penis, which helps them deliver sperm to the female. Many reptiles, such as turtles, are oviparous. Snakes are often ovoviviparous, or they bear living young. • Reptiles have strong limbs and well-developed muscular and skeletal systems. • They use their limbs to walk, swim, burrow, or climb. • Snakes expand and contract the muscles around their ribs in waves, thus moving forward.

33. Birds Chapter 32.3

34. What is a Bird? • Birds are endothermic, reptile-like animals with outer covering of feathers, two legs used for walking and perching, and front limbs modified into wings that usually do not have useful craws. • Birds have three types of feathers: • Contour feathers • Down feathers • Powder feathers

35. Form and Function in Birds Feeding: Respiration: Birds have a highly efficient respiratory system. Part of birds’ respiratory system are air sacs. Air sacs enable bird to remove oxygen from air when they are inhaling or exhaling. • Birds have high metabolic rates and burn many calories to keep warm. • Bird are carnivores, nectar and seed feeders, and insect feeders. • Many birds have organs called crop and gizzard. The crop and gizzard help with digestion.

36. Birds! Internal Transport: Excretion: Birds eliminate nitrogenous wastes by filtering them from the blood in the kidneys. Urine, which contains wastes in the form of uric acid, flows to the cloaca through the ureters. • Birds have a four-chambered heart and two separate circulatory loops. • In order to keep blood moving, a bird’s heart can beat from 150 to 1000 beats every minute.