Animals with backbones Vertebrates Animals with backbones

Characteristics of chordates: 1. Dorsal hollow nerve cord 2. Notochord

3. Gill slits 4. Tail

Most chordates are vertebrates like the fish, amphibians, reptiles, birds and mammals.

A small number are nonvertebrate chordates like the lancelets and the tunicates

Fish Characteristics: Aquatic 2 Paired fins Scales

Gills Ectothermic (cold blooded)

Fins

Structures and functions: Feeding: herbivores, carnivores, omnivores Circulation-closed, 2 chambered heart upper chamber is called the atrium, bottom is ventricle

Excretion-kidneys remove waste from blood response-well developed, brain divided into parts: olfactory-smell optic-sight cerebellum-muscular movement and balance cerebrum-thinking medulla-internal body organs

Most fish have ears but they don’t function well Lateral line on side of fish picks up motion in water

Reproduction: Oviparous-lay eggs (most fish are this)                                               Reproduction: Oviparous-lay eggs (most fish are this) ovoviviparous-eggs develop inside mother but are not nourished by her (sharks) viviparous-live young (guppies)

Depth is controlled by a swim bladder.

Examples 1. Jawless fish hagfish lamprey

2. Cartilaginous sharks skates rays

3. Bony fish-Osteichtheyes ray finned Lobefinned-fleshy fins

Amphibians Characteristics Live in water as larva and on land as adults Skin is moist lack scales and claws ectothermic

Structures and functions: Feeding: Young are filter feeders, adults are carnivores

Circulation -3 chambered heart Respiration Gas exchange in gills when in the water, by lungs, mouth and skin as adults. Circulation -3 chambered heart

Response: Well developed brain and sensory organs Eyes covered with nictitating membrane (protects and keeps eyes moist) Eardrum is called the tympanum

Reproduction: Eggs must be laid in water Male squeezes eggs out of female’s body and then fertilizes them (external)

Examples of amphibians 1. Frogs and toads-lose their tail

2. Salamanders-keep their tails

3. Caecililian-legless, (lives in the tropics)

Importance in the world poisonous (advertise with bright colors) eat insects that damage crops

Reptiles Characteristics Dry scaly skin Larger lungs

Terrestrial eggs Ectothermic

Feeding-some herbivores, some carnivores Respiration-use lungs only, no gills

Internal transport-3 chambered heart except crocodiles and alligators have 4 Excretion-secrete dry waste to conserve water

Response-senses are well developed, brain is larger than fish and amphibians Reproduction-internal fertilization Molting-shedding of skin

Examples of reptiles: 1. Tuatara-found only in New Zealand

2. Lizards and snakes Pit vipers-detect prey with heat sensitive pits on head

Toxins-hemotoxins, neurotoxins

3. Crocodiles and alligators Alligators live in fresh water only, crocodiles in both

4. Turtles and tortoises Shell is part of skeleton generally turtles like water, tortoises land

The evolution of reptiles to birds:

Birds Characteristics: Covered with feathers legs covered with scales Front limbs modified into wings All are endothermic

Feather types: Contour-large flight feathers

Down feathers- found underneath, insulate

Powder feathers-produce powder that keeps bird waterproof Filoplumes- maneuver contour feathers Bristles-around eyes for protection

Structures and functions: Feeding-large amounts of food are required for flight and body temperature. Have a crop for storage of food and a gizzard for grinding.

respiration-they have several air sacs as well as lungs

circulation-4 chambered heart excretion-similar to reptiles, most of the water is retained

Response-a bird has a large brain for its body size Senses are well developed behaviors-nesting, migration, care of young Songs and displays used in courtship and declaring territory

Preening-preen gland located at base of tail used to waterproof feathers Flight-hollow bones, air sacs, strong pectoral muscles, wings, feathers

Reproduction-very high survival rate Internal fertilization Most incubate eggs and care for their young

Feet flightless-broad flat feet perching-long toes to wrap around branches water birds-webbed feet birds of prey-claws (talons)

Beaks tell what they eat Bird of prey Insect eaters

Digs for worms in mud Others may have scoops

Importance of birds: Pollination of flowers and dispersal of seeds

Feathers used for warmth and beauty

Eaten for food Control of insects

Mammals Characteristics: endothermic fur or hair mammary glands to nurse young live birth

Structures and functions: Feeding: a lot of food is required to maintain body temperature Carnivores-sharp tearing teeth Herbivores-flat grinding teeth

Respiration-lungs moved by diaphragm Circulation-4 chambered heart

Response-mammals have the most highly developed brain                                                                                 

Examples: 1. Monotremes-egg laying mammals duck bill platypus, spiny anteater, found in Australia only

2. Marsupials-pouched mammals - kangaroos, koalas, opossums

3. Placental-nutrients and waste exchanged through the placenta a. insectivora-shrews, hedgehogs, moles

b. Chiroptera-bats

c. xenarthrans-without teeth sloth, anteater, armadillo

d. Rodentia-gophers, rats, mice, beavers, squirrels

e. Lagomorpha-rabbits, hares, pikas

f. Carnivora-dogs, cats, bears, seals

g. Cetacea-whales, dolphins, porpoises

h. Sirenia-manatees (sea cows)

i. Arteriodactyla-even toed sheep, goats, giraffes, pigs

j. Perissodactyla-have odd number of toes horses, zebras, rhinos, tapirs

k. Proboscidea-trunks elephants

l. Primates- monkeys, apes, humans