1. Non-vertebrate Chordates, Fishes, and Amphibians
Chapter 30

2. 30-1 What is a chordate?
All chordates show the following traits at some point in their lifetime:
1. Dorsal, hollow nerve cord
2. Notochord
3. Pharyngeal pouches
4. Tail beyond the anus

3. What is a chordate? (cont)
The hollow nerve cord runs along the dorsal part of the body.
The notochord is a long, flexible rod that supports the body.
Found beneath the nerve cord
May be replaced by bone (in vertebrates)

4. What is a chordate? (cont)
Pharyngeal pouches are paired structures in the throat region.
In some chordates, they open to the outside of the body and used for gas exchange.
All chordates have a tail that extends beyond the anus.
It can contain bone and muscle.
Mouse embryo

5. Most Chordates are Vertebrates
About 96% of all chordates are in the subphylum Vertebrata.
Most vertebrates have a backbone.
The anterior end of the vertebrate backbone develops into a brain.
The backbone is made of vertebrae.
The backbone is part of an endoskeleton.

6. Nonvertebrate Chordates
Two groups of nonvertebrate chordates exist:
Tunicates
Lancelets
Both are soft bodied marine organisms.

7. 30-1 What is a fish? Fish are aquatic vertebrates.
Most have paired fins, scales, and gills.
Fish were the first vertebrates to evolve.
The evolution of jaws and the evolution of paired fins were important developments during the rise of the fishes.

8. The Evolution of Fish
Doryaspis
The earliest fish were jawless, armored with bony plates (about 400 million yrs ago).
Jaws allowed fish better feeding ability as well as defense.
Paired fins aided movement and provided more control of movement.
Pacific Hagfish

9. Form & Function in Fish
Fish can be herbivores, carnivores, parasites, filter feeders, and detritus feeders.
Most fish use gills for gas exchange.
Some fish have specialized organs that allow them to survive in oxygen-poor water or in areas where bodies of water often dry up. These specialized organs serve as lungs.
African Lungfish

10. Fish Form & Function (Cont)
Fish have a complete digestive system (alimentary canal).
Fish have a closed circulatory system with a two chambered heart that pumps blood.
Fish are ectothermic.
Most fish rid themselves of nitrogenous wastes in the form of ammonia through the gills and kidneys.

11. Fish Form & Function (Cont)
Fish have well-developed nervous systems and highly developed sense organs.
The lateral line system can detect gentle currents and vibrations in water with sensitive receptors.

12. Fish Form & Function (Cont)
The swim bladder is found in bony fish.
The swim bladder is an internal, gas-filled organ that can adjust the buoyancy. It lies just beneath the back bone.

13. Fish Form & Function (Cont)
Fish whose eggs hatch outside the mother’s body are oviparous. The embryos obtain food from a yolk in the egg.
Fish that retain the eggs after fertilization are called ovoviparous. Embryos use the yolk for nourishment. The young are “born alive”.
Viviparous animals develop in the mother’s body and obtain nourishment from the mother’s body. (Fish are not viviparous.)

14. Classification of Fish
All living fish can be classified into 3 groups:
1. Jawless fish (Agnatha)
2. Cartilaginous Fish (Chondrichthyes)
3. Bony fish (Osteichthyes)

15. The Jawless Fish
Jawless fish (Class Agnatha) have no true teeth or jaws.
Their skeleton is made of fibers and cartilage.
They lack vertebrae and retain their notochord as adults.
They have fish-like bodies, no scales, and unpaired fins.
Two types: Hagfish & Lampreys.
Hagfish
Lamprey

16. Cartilaginous Fish Belong to Class Chondrichthyes.
Includes sharks, skates, rays.
The skeleton is entirely cartilage (no bone).
Possess tooth-like scales.
Gills are not protected with bony covering.

17. Bony Fish Belong to Class Osteichthyes. Skeletons are made of bone.
Divided into two groups
Ray-finned fish (have bony spines or rays in the fins)
Perch
Trout
Lobe-finned fish (fleshy fins have bones)
Lungfish
Coelocanth
Trout
Coelocanth

18. 30-3 Amphibians
An amphibian is a vertebrate that, with some exceptions, lives in water as a larva and on land as an adult, breathes with lungs as an adult, has moist skin that contains mucus glands, and lacks scales and claws.
The first amphibians probably resembled lobe-finned fish but had legs.
There were challenges to surviving on land
Terrestrial vertebrates have to breathe air, protect themselves (and eggs) from drying out, and support against the pull of gravity.

19. Evolution of Amphibians
Early amphibians evolved several adaptations to land:
Bones in the limbs and limb girdles became stronger, permitting better movement
Lungs and breathing tubes aided gas exchange
A sternum formed a shield to support and protect the internal organs
Most amphibians became extinct at the end of the Permian Period. Only 3 orders of small amphibians still exist: frogs and toads, salamanders, and caecilians.

20. Amphibian Form & Function
Tadpoles are typically filter feeders or herbivores; as adults they become meat eaters.
Amphibians have a complete digestive system.
Respiration occurs through the skin and gills (tadpoles) or via the skin and lungs (adults).
Lungless amphibians use the thin lining of the mouth cavity and the skin.

21. Amphibian Form & Function
Amphibians have a closed circulatory system with a 3 chambered heart (two atria and a ventricle).
Amphibians are ectothermic.
A pair of kidneys removes metabolic wastes from the blood and form urine. Urine can be stored in the urinary bladder and excreted through the cloaca.

22. Amphibian Form & Function
Because amphibian eggs lack a shell, the eggs must be kept moist.
In most species, females lay the eggs in water. Fertilization is external.
Eggs are covered with a sticky jelly.
Most amphibians abandon their eggs after laying them.

23. Amphibian Classification
Salamanders have long bodies and tails. Most have four legs. Adults and larvae are carnivores.
Frogs and toads share their ability to jump. Frogs tend to have long legs and jump longer. Frogs are more closely tied to water. Adult frogs and toads lack tails.
Caecilians are legless amphibians that live in water or burrow in moist soil.

24. Reptiles & Birds
Chapter 31

25. What is a reptile?
A reptile is a vertebrate that has dry, scaly skin, lungs, and terrestrial eggs, with several membranes.
Reptilian skin is dry and often covered with thick scales.
Scaly skin must be shed periodically.
Reptiles were the first animals to lay shelled eggs (amniote eggs).
Reptiles evolved from amphibian-like ancestors.

26. Reptile Form & Function
Reptiles are ectothermic.
Gas exchange is always via lungs.
Reptiles have a 3 chambered heart with a partially divided ventricle.
Kidneys remove metabolic wastes.
All reptiles use internal fertilization. Most males have a penis-like organ that allows them to deliver sperm into the female’s cloaca.
Reptiles are oviparous or ovoviviparous.
Legs have clawed toes.

27. Reptile Eggs
The amnion is a fluid-filled sac that surrounds and cushions the embryo.
The chorion regulates gas exchange.
The yolk sac contains a nutrient-rich food supply.
The allantois stores metabolic wastes.
The shell is impermeable to water and to sperm.
The amniote egg is one of the most important adaptations to life on land.
Crocodile eggs

28. Reptile Classification
There are four surviving groups of reptiles:
1. Lizards and Snakes
2. Crocodilians
3. Turtles and Tortoises
4. Tuataras

29. What is a bird?
Birds are reptile-like animals that maintain a constant internal body temperature. They have an outer covering feathers; two legs that are covered with scales and are sued for walking or perching; and front limbs modified into wings.
The single most important trait separating birds from other vertebrates is feathers.

30. Bird Feathers Feathers are made mostly of protein (keratin).
Feathers help birds fly and keep them warm.
Preening allows birds to rub oil on the feathers to keep them water resistant.
Though all birds have wings and feathers, not all birds can fly.

31. Form & Function of Birds
Birds are endothermic.
The mouth lacks teeth and is modified into a beak.
Lacking teeth, birds have specialized structures to help digest food.
A crop at the lower end of the esophagus stores and moistens food. It can also be used to store nutrient rich food to feed baby birds.
The gizzard is a muscular organ that may contain small rocks to help grind food.
gizzard

32. Bird Form & Function
Bird lungs have many air sacs to increase gas exchange.
Birds have a 4 chambered heart and are endothermic.
Light-weight bones aid flight.
Birds that fly have only one gonad and no urinary bladder.

33. Bird Reproduction
Both male and female reproductive tracts empty into the cloaca.
Bird eggs are amniotic.
Most birds incubate their eggs until the eggs hatch.
Both parents may be involved in raising the offspring.

34. Bird Classification Nearly 30 orders of birds exist.
The largest order of birds includes the perching birds (songbirds). There are nearly 5000 species of perching birds.

35. Mammals
Chapter 32

36. What is a mammal? Mammals have milk producing mammary glands.
Mammals have hair covering the body.
All breathe air with lungs, have 4 chambered hearts, and are endothermic.

37. Mammal Form & Function
Endotherms have a much higher metabolic rate than other chordates.
Hair and a layer of subcutaneous fat helps keep mammals warm.
Sweat glands help cool the body. Panting is a way that mammals without sweat glands can cool the body.

38. Mammal Form & Function High metabolic rates require more food intake.
Mammals can be herbivores, carnivores, or omnivores.
Jaws and teeth are specialized.
Incisors
Canines
Premolars
Molars
Herbivores have a rumen (stomach chamber) that contains symbiotic bacteria to digest the cellulose.

39. Mammal Form & Function All mammals use lungs.
A powerful muscle called the diaphragm aids breathing.
Mammals have a powerful 4 chambered heart.
Kidneys are used to remove metabolic wastes in the form of urea.

40. Mammal Form & Function Mammals reproduce by internal fertilization.
All offspring feed on the mother’s milk.
Offspring are cared for by one or both parents.
Mammals are classified into 3 groups based on their mode of development and birth.

41. Mammal Diversity & Classification
The three groups of mammals are
1. Monotremes (egg laying)
2. Marsupials (pouched mammals)
3. Placentals (develop in a uterus and are nourished by a placenta)

42. The Orders of Mammals Order Monotremata Order Marsupialia Egg laying
Includes platypus and echidna
Order Marsupialia
Pouched mammals
Bear live young but at a very early stage of development
Young complete development in a pouch (marsupium)

43. Orders of Mammals Order Insectivora Order Sirenia Insect eaters
Long narrow snout
Sharp claws well suited for digging
Includes shrews, hedgehogs, moles
Order Sirenia
Herbivores that live in rivers and bays
Large, slow-moving aquatic mammals
Manatees

44. Orders of Mammals Order Cetacea Order Chiroptera
Adapted to life underwater
Have a blow hole
Whales, dolphins, porpoises
Order Chiroptera
Winged mammals
Only mammals capable of true flight
Eat mostly insects and fruit
Bats

45. Orders of Mammals Order Carnivora Order Rodentia
Have sharp canines for catching prey
Sharp claws
Dogs, foxes, bears, cats, walruses
Order Rodentia
Single pair of long, curved incisors for gnawing
Mice, rats, voles, squirrels, beavers, gerbils

46. Orders of Mammals Order Artiodactyla Order Perissodactyla
Even toed hoofed mammals
Mostly large, grazing animals
Cattle, sheep, goats, pigs, giraffes, hippopotamus, camels, deer
Order Perissodactyla
Odd toed hoofed mammals
Horses, tapirs, rhinoceroses, zebras

47. Orders of Mammals Order Lagomorpha Order Proboscidea
Herbivores with two pairs of incisors
Adapted for running and jumping
Rabbits, hares
Order Proboscidea
Trunk-nosed mammals
Elephants

48. Orders of Mammals Order Primata Order Xenarthra
Highly developed cerebrum and complex behaviors
Five digits on hands and feet
Lemurs, tarsiers, apes, gibbons, humans
Order Xenarthra
Simple teeth without enamel; some with no teeth at all
Sloths, anteaters, armadillos