Vertebrates

1. Vertebrates

2. Fishes • All fishes are ectotherms. • Ectotherms- animals with body temperatures dependent upon the temperature of their surroundings. • Fish have a two chambered heart and breath through gills. • Different types of fishes are grouped into three different classes, jawless fishes, cartilaginous fishes and bony fishes.

3. Fishes cont. Jawless Fishes • Types of jawless fishes are lampreys and hagfishes. • Jawless fish have endoskeletons made of cartilage like sharks and types of rays.

4. Fishes cont. Cartilaginous fishes • Types of cartilaginous fishes are sharks, skates and rays. • Evidence has proven that jaws were first evolved in this type of fish. • Cartilaginous fish have endoskeletons made of cartilage like jawless fish. • Cartilaginous fish have paired fins and a lateral line system that enables them to detect movement and vibrations in water.

5. Fishes cont. Bony Fishes • Most fishes belong to the bony fish class. • All bony fishes have a bony skeleton, gills, paired fins, flattened bony scales and a lateral line system. • Bony fishes breath by drawing in water into their mouth then passing it over the gills where gas exchange occurs. • They adjust their depth in the water by regulating the amount of gas that diffuses out of their blood into the swim bladder.

6. Amphibians • Amphibians are ectothermic with three chambered hearts, lungs and thin moist skin. • Most gas exchange is carried out through the skin not the lungs. • Adult amphibians live on land but rely on water for reproduction. • Almost all amphibians go through the process of metamorphosis. • Metamorphosis- which the young hatch into tadpoles, then gradually lose their tails and gills as they develop legs, lungs and other adult structures. • Amphibians can be classified into three orders Anura, Caudata and Apoda.

7. Amphibians cont. • Anura are considered to be frogs and toads. • Anuras have vocal cords that can produce wide range sounds. • Frogs have think, smooth, moist skin. • While toads have thick bumpy skin with poison glands. • Caudata are considered to be salamanders and newts. • Salamanders have long, slender bodies with a neck and tail. • Apoda are considered to be legless caecilians. • Caecilians have long, wormlike bodies with no legs.

8. Reptiles • Reptiles are ectotherms with dry, scaly skin and clawed toes. • Types of reptiles are snakes, lizards, turtles, crocodiles and alligators. • All reptiles have four legs that are positioned under the body except snakes. • Most reptiles have a three chambered heart except for a crocodile it has a four chambered heart. • The scaly skin of reptiles reduces the loss of moisture on land scales also prevent the skin from absorbing or releasing gas. • Reptiles are dependent on lungs for the essential gas exchange. • Reptiles lay amniotic eggs to reproduce.

9. Birds • Birds are the only class of animals to have feathers. • Feathers are lightweight, modified scales, that help insulate birds and enable them to fly. • They have wings which are modified forelimbs. • Similar to reptiles birds have scales on their feet and clawed toes. • Unlike reptiles they are endotherms. • Endotherms- animals that maintain a constant body temperature. • Endotherms must eat frequently to provide energy needed for producing heat.

10. Birds cont. • Birds have thin hallow bones with cross braces that provide support for strong flight muscles while reducing their body weight. • Birds have a four chambered heart. • Birds have a unique respiratory system which oxygen is available through exhalation and inhalation. • Like reptiles birds lay amniotic eggs but unlike reptiles birds incubate their eggs in nests. The nest keeps the egg warm till the young birds hatch.

11. Mammals • Mammals are endotherms. • Mammals are named after their mammary glands, which produces milk to feed their young. • Most mammals have hair which is used to help insulate their bodies and sweat glands that help keep them cool. • Mammals need a high energy level for maintaining body temperature and high speeds of locomotion. • Mammals have a efficient four chambered heart and muscular diaphragm beneath the lungs to help deliver oxygen for their activities.

12. Mammals cont. • All mammals have internal fertilization and the young begin development inside the mothers uterus. • Mammals are divided into three large groups monotremes, marsupials and placental. • Monotremes are mammals that lay eggs. • Marsupials are mammals which the young complete a second stage of development after birth in a pouch made of skin and hair on the outside of the mothers body. • Placental mammals carry their young inside the uterus until development is nearly complete. • Mammals can also be classified by their teeth, how many they have and type. • Types of teeth are incisors, canines, molars and premolars. • Incisors are used to cut food. • Canines are long pointed teeth used to stab or hold food. • Molars or premolars have flat surfaces with ridges and are used to rind and chew food.