VERTEBRATES and their Classification

Vertebrate Classes:

Pisces: (fish)Agnatha (jawless fish)Chondricthes (boneless fishOsteicthes (boney fish)

Tetrapoda (four limbed creatures)AmphibiaReptiliaAvesMammalia

General Vertebrate Characteristics

Vertebrates typically have bilateral symmetry in their skeleton and in their muscular, respiratory, nervous, circulatory, and urogenital systems. Their two pairs of limbs are adapted for different uses, such as wings for flying or fins for swimming.

In most vertebrates, a hollow, jointed backbone and its upper extension, the cranium, protect the spinal cord and brain. Almost all young vertebrates have gill slits in their embryonic stage. In land vertebrates the gills develop into lungs. All vertebrates reproduce sexually, and males and females have distinct characteristics.

FISH CHARACTERISTICS

Cold Blooded Live in water Use gills

instead of lungs Usually have

scales

Eggs have no shells

Eggs are laid in large quantities; no care is given to young

Pisces:Agnatha….Jawless fish

. The lamprey and hagfish, known as cyclostomes,

Jawless fishes obtain their food by sucking.

Jawless fish are parasites. Lampreys are a “foreign

invader” problem fish in the Great Lakes. How did this happen?

Pisces: Chondrichthes

The Chondrichthyes include sharks, skates, and rays, The skeletons of Chondrichthyes contain no bones but instead are made entirely of cartilage.

Sharks are voracious predators and powerful swimmers with well-developed paired fins and strong tails.

Pisces: Chondrichthes

Skates and rays have flattened bodies, and their pectoral fins are greatly expanded.

This is a Sawfish. They obtain food by using their long snouts to dig out bottom animals or to lash out against schooling fishes.

Pisces: Osteicthes…Bony Fish

This group is divided into the Actinopterygii and the Sarcopterygii. The Actinopterygii, or ray-finned fishes, have about 20,000 known species. The ray-finned fishes get their name from the fact that their paired fins are webs of skin supported by rays of bone. Most of these fish belong to the Teleostei group, which has the largest number of species among the vertebrates. Their complex jaw and associated muscles enable them to eat a wide range of foods. They are also highly prolific breeders, with a single female capable of producing up to 9

million eggs in one season. Examples

Pisces: Osteicthes: bony fish

The Sarcopterygii, though smaller have fewer members.They were long thought to have become extinct, but in 1938 a representative of this group, a coelacanth, was caught off the coast of Africa. Since then others have been found in the Indian Ocean. Coelecanth Fossil

Living Coelecanth Living Coelecanth

Amphibian Characteristics Cold Blooded Part of the life cycle is

spent on land, and part in water

Adults have lungs and yet may breathe through skin

Three chambered heart

Eggs are laid in water

There is no shell on eggs

Eggs are laid in large numbers, and no care is given to the young

Tetrapoda: Amphibians: Two Lives

Members of this class still spend the early part of their lives in water and return to it during their reproductive cycle.

The 3,000 species of modern amphibians are divided into frogs and toads (Anura), newts and salamanders (Urodela), and burrowers in the Gymnophiona group. The anuran skeleton is modified to make jumping possible.

Tetrapoda: Amphibians: Two Lives

The urodeles are the tailed amphibians. All of them resemble the most numerous members of this order the salamanders. Basically animals of the Northern Hemisphere, urodeles live in or near streams, and are sometimes found under rocks and logs. They have long tails, poorly developed legs, and smooth, moist skin.

Reptilian Characteristics

Cold blooded with three chambered heart Air breathing Covered with scales or plates Feet have toes with claws The excretory system can minimize water loss Eggs are leathery, and can be laid in air or

soil, rather than in water

Tetrapoda: Reptilia

The Reptilia class of vertebrates live their entire life span on dry land. This is made possible by the hard eggshell, which protects the egg from drying out. The egg contains food that sustains the developing young until it hatches.

The major reptile groups are turtles and tortoises, Squamata (lizards and snakes), and Archosaurs (now-extinct dinosaurs and modern-day alligators and crocodiles).

Tetrapoda;Reptilia: Turtles

About 250 species of turtle are found throughout the temperate and tropical regions of the world, including the major seas. In contrast to other reptiles, whose populations are confined largely to the tropics, turtles are most abundant in southeastern North America and southeastern Asia. They live in lakes, ponds, salt marshes, rivers, forests, and even deserts.

The carapace is made of backbone and ribs joined together with plates of bone. The plastron is fused with the breastbone. In hard-shell turtles the bone is covered with horny shields

Tetrapoda:Reptilia:Squamata:Lizards and Snakes

Lizards are widespread in the tropics where they occur in great variety from horned toads to the monitor lizard, which measures up to 13 feet (4 meters) in length, of the East Indies.

Snakes primary characteristics are lack of limbs; movement by undulating the body and tail; a highly flexible skull and jaw that allows them to swallow their prey whole; and, in some families of snakes, poison glands and hollow fangs.

Tetrapoda: Reptilia:Archosaurs:Crocodiles and Alligators

Modern-day alligators and crocodiles are the only surviving members of the Archosaurs. These amphibious reptiles use four limbs for locomotion. Alligators live in fresh water and crocodiles in salt water.

The term crocodilian is applied to any of the order Crocodilia alligators, caimans, and gavials, as well as true crocodiles. There are about 20 species of living crocodilians, all of which are

lizardlike, egg-laying meat-eaters.

Tetrapoda: Aves (Birds) Scientists have classified some 8,700 species of birds that inhabit the Earth today. The characteristic features of the class Aves include:

• warm blooded with high speed metabolism and four chambered heart•feathers that form the wing surfaces of modified forelimbs, hollow bones, •air sacs distributed throughout the body, •a horn bill without any teeth, •lay a few eggs with hard shells, often incubate eggs and raise their young

Many birds eat grain and seeds. Lacking teeth, they have developed a grinding mechanism. They swallow grit or small pebbles, which are held in a gizzard, a part of the digestive tract. There the stony particles grind the seeds so they can be digested. Birds have well-developed nervous systems and demonstrate complex patterns of behavior in courtship, nest building, and rearing their young.

Bird Beaks

Bird beaks never have teeth though!!!

Mammalian Characteristics warm blooded with four chambered heart air breathing bear live young and parents raise young have hair or fur sophisticated brains nurse the young through mammary glands an outer ear which collects sound separate chest and abdominal cavities

MONOTREMESMonotremata. Duck-billed platypuses and spiny anteaters. MARSUPIALS Marsupialia. Kangaroos, wallabies, opossums, wombats, koalas. PLACENTAL MAMMALSInsectivora (insect eaters). Shrews, moles, hedgehogs.Dermoptera. Colugos or flying lemurs.Chiroptera. Bats.Primates. Tree shrews, lemurs, monkeys, marmosets, great apes, humans.Edentata. Sloths, armadillos, anteaters.Pholidota. Pangolins or scaly anteaters.

Lagomorpha. Hares, rabbits, pikas.

Rodentia (gnawers). Mice, rats, squirrels, porcupines, beavers.Cetacea. Dolphins, porpoises, whales.Carnivora (flesh eaters). Cats, dogs, bears, weasels, hyenas, racoons, badgers.Pinnipedia. Seals, sea lions, walruses.Tubulidentata. Aardvarks.Proboscidea. Elephants.Hyracoidea. Hyraxes, dassies.Sirenia. Manatees, sea cows, dugongs.Perissodactyla (odd-toed hoofed animals). Horses, asses, zebras, tapirs, rhinoceroses.Artiodactyla (even-toed hoofed animals). Pigs, cattle, sheep, goats, antelopes, alpacas, camels, deer, giraffes, hippopotamuses.

Classes of Mammalia

Mammalia: Tetrapoda: Monotreme

Native only to Tasmania and eastern and southern Australia, the platypus is the sole member of the mammal family Ornithorhynchidae.

It is one of two animals that form the order Monotremata (egg-laying mammals), the other being Australia's spiny anteater.

The platypus, also known as the duckbill, watermole, or duckmole, is a shy, reclusive animal that lives near lakes and streams.

The female has no nipples; instead, milk oozes through slits in her abdomen where it is licked up by the young.

Tetrapoda: Mammalia: Marsupials

Mammals that carry their young in an abdominal pouch during their early development are called marsupials. Soon after the marsupial ovum, or egg, is fertilized, the young are born in a premature state and crawl into the mother's pouch. There, nursing on milk from their mother's nipples, they complete their development.

Opossum

Mammalia: Tetrapoda: Placental Mammals

What is a Placental Mammal?

More than 95% of all mammals are placentals. The egg remains inside the mother and is fed via a placenta. The circulatory systems of the mother and embryo are never mixed. Nutrients and oxygen from the mother’s blood pass through the placenta into the developing embryo, and waste materials pass out.

Because the developing mammals get their nourishment directly from the mother, development is not limited to the amount of food that can be found in the egg.The longer gestation period or pregnancy, permits the formation of a complex brain and nervous system.