Bio Notes for Final Exam Animal Evolution The Chordates Phylum Chordata The name chordate comes from notochord All of these animals have chordate Traits Notochord a rod of stiff but flexible connective tissue extends the body in length and provides support Dorsal hollow nerve cord parallels notochord has a central canal Pharyngeal gill slits Muscular tail gill slits open across wall of pharynx extends beyond anus Invertebrate chordates There are 2 groups of soft bodies chordates that live only in the sea Ex Tunicates the body is vase like with 2 openings A carbohydrate covering called the tunic covers the whole body Between the tunic and the body is a space called the atrium Pharynx is large with many openings Pharynx catches food and absorbs oxygen A stomach and intestine are present Hermaphrodites release eggs and sperm into the sea Tadpole looses all chordate traits expect the gills when they grow into adults trait number 3 Ex Lancelets tentacles Also called amphioxus marine fish shaped mouth surrounded by Pharynx with gill slits Atrium surround pharynx water flows out of it Intestine and liver segmented muscles tail fin Amphioxus Has an eye spot Live burned in sand Sexes separate eggs hatch into larvae Settle down and develop into adults Internal skeleton skull and backbone paired limbs legs and arms Vertebrates fish amphibians reptiles birds and mammals Vertebrates characteristics Bilateral symmetry Skin with scales or smooth feathers or hair Pharyngeal gills or lungs Digestive system with liver stomach intestine pancreas pair of kidneys Sexes are separate Lay eggs or live birth Jawless fish lampreys and hagfish Parasites of fish cold blooded smooth skin no scales no jaws circular mouth with teeth a tongue to bore into host s flesh Only dorsal and tail fin Have notochord and nerve cord Sexes separate Marine lampreys migrate to lakes to spawn Eggs hatch into ammocoetes larvae Live in sea and freshwater some hagfish species occur in deep oceans Sharks Skates and rays and tail fins Mostly marine torpedo shaped body pair of pectoral fins and pelvic fins dorsal 5 7 gills large liver cold blooded Skeleton made of cartage no bones Skin with small scales called denticles teeth like with enamel and dentine Well developed eyes sense of smell Sexes separate most species lay eggs some give live birth nurse shark Most species carnivorous whale sharks and manta ray feed on plankton Some attack humans Great white shark Some skates sharks use a mermaid s purse to hold the eggs and produce the baby in that Internal bony skeleton 4 pairs of gills covered by an operculum Bony Fish Live in freshwater and in the sea Cold blooded Skin with scales pair of pectoral and pelvic fins dorsal and tail fins Gas bladder to help buoyancy Sexes separate Some tropical species give live birth rest of the species lay eggs Salmon eggs hatch in rivers juveniles migrate to the sea and mature Adults return to birth places and spawn Eels live in marshy areas adults migrate to the Atlantic to spawn Largest fish is the sunfish or mola Sport fish swordfish marlin sailfish tarpon etc Anal fin found on only bony fish Schooling fish Anchovy sardine herring tuna etc Amphibians Salamanders newts and frogs Cold blooded Skin smooth with mucous glands and poison glands Some salamanders are legless live in South America Africa and Asia Salamanders and frogs are tetrapods Tadpoles have gills and adults have lungs Salamander larvae have external gills mud puppy Frogs and toads have longer back legs for hopping Frog eggs hatch into tadpoles and go through metamorphosis Tadpoles feed off plants Land Vertebrates The Amniotes retiles birds and two species of mammals Vertebrates that live on land either lay eggs or give live birth Egg layers Some retiles give birth to live young garter snakes rattle snakes Animals that give live birth The eggs of land vertebrates may be enclosed in a shell or may grow directly in the mammals female s uterus mammals The egg is called an amniotic egg The four membranes are Amnion forms an envelope around the embryo Chorion forms a lining on the inside of the egg Yolk sac carries yolk for the embryo reptiles and birds in mammals it is Allantois stores wastes until the eggs hatches in mammals it becomes a rudimentary part of the umbilical cord Reptiles Turtles tortoises snakes lizards alligators and crocodiles Cold Blooded Eggs are amniotic Turtles and tortoises have a dorsal and ventral shell tortoises have claws have no Have scales shell or plates making turtle shells teeth but a beak Sea turtles migrate to seashores to lay eggs Snakes and lizards have scales snakes have no legs all have forked tongues Some snakes species are poisonous rattle snake vipers cobras etc Some snakes hold the eggs until they hatch and give birth rattle snake Alligators and crocodiles have thick plates in skin Nostrils have valves to close them when alligators go under water Females guard the eggs and protect juveniles for a period Dinosaurs lived between 120 and 65 millions years ago became extinct Birds Smallest I humming bird largest is ostrich Warm Blooded Have feathers contour tails downs and flight feathers Beaks no teeth Many bones in legs and wings are fused to make the skeleton rigid Large keel bones for attachment of flight muscles white male Have air sacs attached to lungs for extra air Varieties of beaks and lags webbed feet in ducks and water birds Extremely well developed eye sight Some species migrate in spring and fall ducks artic tern humming birds etc Separate sexes lay amniotic eggs Parental care of young Flightless species ostrich emu cassowary rhea penguins and kiwi Mammals Monotremes marsupials and placental mammals Warm blooded Hair mammary glands and live birth except monotremes Duck billed platypus and echidna live in Australia and they lay eggs Marsupials are also Australian except for opossum in the Americans Marsupial young are born premature and they crawl into pouches All other species are placental have placenta to attach fetus to the uterus Chest and abdomen are separated by a diaphragm Some are marine dolphins and whales manatees seals and sea lions Large mammals giraffe elephants small ones mice shrew Economic species cattle sheep and goats llamas and alpacas Animals used in labor camels and elephants Monkeys and great apes are closely related to humans Primates Migratory species wildebeest zebra whales manatees etc Some species can fly bats some glide flying squirrel Primates This order