phylum+chordata

ZOOLOGY NOTES—PHYLUM CHORDATA SUPERCLASS AGNATHA: JAWLESS FISHES CLASS MYXINI—HAGFISHES Ø MARINE SCAVENGERS WHICH FEED ON DEAD OR DYING FISHES, ANNELIDS, MOLLUSCS, AND CRUSTACEANS Ø HAVE VERY WELL-DEVELOPED SENSES OF SMELL AND TOUCH, BUT ARE ALMOST BLIND Ø CAN TIE A KNOT IN ITS TAIL WHICH IT PUSHES FORWARD TO HOLD ITS PREY Ø PRODUCES HUGE AMOUNTS OF SLIME AND IS ALMOST IMPOSSIBLE TO GRASP CLASS PETROMYZONTES—LAMPREYS ü BOTH FRESHWATER AND MARINE SPECIES EXIST ü ALL LAMPREYS MOVE UPSTREAM INTO FRESHWATER RIVERS AND STREAMS TO SPAWN: SOON AFTER THE EGGS ARE LAID AND FERTILIZED, THE ADULTS DIE ü ABOUT HALF OF THE LAMPREYS IN NORTH AMERICA ARE PARASITIC ü NONPARASITIC LAMPREYS DO NOT FEED AFTER THEY BECOME ADULTS ü SEA LAMPREYS MIGRATED INTO THE GREAT LAKES IN THE EARLY 1900S AND CAUSED CONSIDERABLE DAMAGE TO THE FISHING INDUSTRY CLASS CHONDRICHTHYES: CARTILAGINOUS FISHES v SKELETON MADE OF CARTILAGE v BODY COVERED WITH PLACOID SCALES WHICH FEEL ROUGH v TWO-CHAMBERED HEART WITH ONE ATRIUM AND ONE VENTRICLE v BREATHE WITH GILLS v NO SWIM BLADDER v INTERNAL FERTILIZATION v INCLUDES SHARKS, SKATES, AND RAYS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v ALMOST ALL ARE MARINE SUBCLASS ELASMOBRANCHII: SHARKS, SKATES, AND RAYS <span style="font-family: 'Courier New'; mso-fareast-font-family: 'Courier New'; msofareastfontfamily: 'Courier New'; msolist: Ignore;">o CARNIVORES WHICH USE THEIR LATERAL LINE SYSTEM AND LARGE OLFACTORY ORGANS (FOR SMELL) TO TRACK THEIR PREY <span style="font-family: 'Courier New'; mso-fareast-font-family: 'Courier New'; msofareastfontfamily: 'Courier New'; msolist: Ignore;">o SOME SHARKS BEAR LIVE YOUNG, WHICH THE FEMALE MAY GESTATE FOR UP TO 2 YEARS <span style="font-family: 'Courier New'; mso-fareast-font-family: 'Courier New'; msofareastfontfamily: 'Courier New'; msolist: Ignore;">o WORN-OUT TEETH ARE REPLACED BY DEVELOPING TEETH WHICH LIE BEHIND THEM <span style="font-family: 'Courier New'; mso-fareast-font-family: 'Courier New'; msofareastfontfamily: 'Courier New'; msolist: Ignore;">o STINGRAYS HAVE A LONG TAIL WITH SPINES WHICH HAVE VENOM GLANDS AT THE BASE <span style="font-family: 'Courier New'; mso-fareast-font-family: 'Courier New'; msofareastfontfamily: 'Courier New'; msolist: Ignore;">o ELECTRIC RAYS HAVE ELECTRIC ORGANS ON THE SIDE OF THE HEAD WHICH PUT OUT A LOW VOLTAGE CHARGE, BUT PUT OUT SEVERAL KILOWATTS OF POWER—ENOUGH TO STUN ITS PREY OR DISCOURAGE PREDATORS CLASS OSTEICHTHYES—THE BONY FISH SUBCLASS ACTINOPTERYGII SUBCLASS SARCOPTERYGII <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v FLESHY-FINNED FISHES: SIX SPECIES OF LUNGFISH AND THE COELOCANTH <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v TAIL FIN CONNECTS WITH THE DORSAL AND VENTRAL MEDIAN FINS TO FORM A SINGLE FIN <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v AUSTRALIAN LUNGFISH CAN LIVE IN WATER WITH A LOW OXYGEN CONTENT BY COMING TO THE SURFACE AND GULPING AIR INTO ITS ONE LUNG, BUT CANNOT LIVE OUT OF THE WATER <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v SOUTH AMERICAN AND AFRICAN LUNGFISH CAN LIVE OUT OF THE WATER FOR EXTENDED PERIODS: AFRICAN LUNGFISH BURROW INTO THE MUD AS DRY SEASON APPROACHES AND FORMS A ‘COCOON’ OF MUD AND SLIME <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v COELOCANTHS WERE BELIEVED TO BE EXTINCT UNTIL A FRESH CARCASS WAS FOUND OFF THE COAST OF SOUTH AMERICA IN 1938; MANY HAVE BEEN CAUGHT SINCE, BUT DIE QUICKLY STRUCTURAL AND FUNCTIONAL ADAPTATIONS OF FISHES 1) LOCOMOTION IN WATER   2)  BUOYANCY: THE SWIM BLADDER 3) RESPIRATION   4)  OSMOTIC REGULATION 5) FEEDING BEHAVIOR  * MORE TIME AND ENERGY IS DEVOTED TO SEARCHING FOR FOOD AND EATING THAN TO ANY OTHER ACTIVITY   *MOST FISHES ARE CARNIVORES—MANY OF THEM USE PHARYNGEAL TEETH LOCATED IN THE THROAT TO GRIND THEIR FOOD   OTHER FISHES ARE HERBIVORES, OMNIVORES, SCAVENGERS, OR PARASITES   6)  MIGRATION—EELS *SPEND MOST OF THEIR LIVES (8-15 YEARS) IN FRESH WATER, BUT MIGRATE TO THE SEA TO SPAWN *ADULTS LEAVE THE RIVERS OF EUROPE AND NORTH AMERICA, SWIM FOR 1-2 MONTHS TO REACH THE SARGASSO SEA SOUTHEAST OF BERMUDA, SWIM TO A DEPTH OF 300 METERS OR MORE, SPAWN AND DIE *AFTER HATCHING, THE LARVAE SWIM BACK TOWARD EUROPE. AFTER ABOUT 3 YEARS, THEY REACH THE RIVERS OF EUROPE AND METAMORPHOSE INTO “ELVERS”, WHICH ARE YOUNG EELS 7) MIGRATION—HOMING SALMON  MOVEMENT TO LAND  *TETRAPODS ARE VERTEBRATE GROUPS THAT LIVE ON LAND  *THERE IS AT LEAST 20 TIMES MORE OXYGEN IN AIR THAN IN WATER  *AIR IS ABOUT 1000 TIMES LESS BUOYANT THAN WATER, SO PROVIES LESS SUPPORT AGAINST GRAVITY—A STRONG SKELETON MUST BE PRESENT  *TEMPERATURE LEVELS ARE MORE VARIED THAN IN WATER; VARIOUS ADAPTATIONS ARE MADE  GENERAL CHARACTERISTICS OF AMPHIBIANS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø  BONY SKELETON <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø  SUSUALLY FOUR LIMBS (TETRAPOD) <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø  SMOOTH, MOIST SKIN—NO SCALES <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø RESPIRATION BY LUNGS, SKIN, GILLS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø THREE-CHAMBERED HEART—DOUBLE CIRCULATION <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø ECTOTHERMAL <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø EXCRETORY SYSTEM WITH PAIRED KIDNEYS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø DIOECIOUS ORDER APODA—CAECILIANS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü LIMBLESS, BURROWING AMPHIBIANS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü MAINLY FOUND IN SOUTH AMERICA; SOME ALSO IN AFRICA AND SOUTHEAST ASIA <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü LONG, SLENDER BODY <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü ALMOST BLIND AS ADULTS; SPECIAL SENSORY TENTACLES FOUND ON THE SNOUT <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü CARNIVORES, FEEDING MAINLY ON WORMS AND SMALL INVERTEBRATES ORDER CAUDATA—SALAMANDERS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ HAVE A TAIL <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ FOUND IN NORTHERN TEMPERATE REGIONS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ MOST ARE SMALL; JAPANESE GIANT SALAMANDER MAY BE MORE THAN 1.5 METERS LONG <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ CARNIVORES, FEEDING ON WORMS, SMALL ARTHROPODS AND SMALL MOLLUSCS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ FERTILIZATION OCCURS INTERNALLY AFTER THE FEMALE PICKS UP A PACKET OF SPERM THAT HAS BEEN DEPOSITED ON A LEAF OR A STICK BY THE MALE <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ EGGS PRODUCE LARVAE WITH GILLS AND A FINLIKE TAIL IN AQUATIC FORMS; TERRESTRIAL FORMS DO NOT UNDERGO METAMORPHOSIS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ METAMORPHOSIS, IF PRESENT, IS STIMULATED BY THE PRESENCE OF A THYROID HORMONE CALLED THYROXINE ORDER ANURA—FROGS AND TOADS 1) TOUGH, DRY, SCALY SKIN   2)  SHELLED (AMNIOTIC) EGG *CONTAINS FOOD AND PROTECTIVE MEMBRANES FOR SUPPORTING EMBRYONIC DEVELOPMEN ON LAND *YOUNG ARE BORN WITH LUNGS FOR IMMEDIATE SURVIVAL ON LAND 3) JAWS FOR CRUSHING OR GRIPPING FOOD   *MUSCLES ARE STRONGER THAN THOSE FOUND IN THE AMPHIBIANS   4)  COPULATORY ORGAN FOR INTERNAL FERTILIZATION *SPERM MUST REACH THE EGG BEFORE THE SHELL FORMS 5) MORE EFFICIENT CIRCULATORY SYSTEM   6)  BETTER LUNG DEVELOPMENT 7) WATER CONSERVATION  *URINE IS TYPICALLY A SEMI-SOLID TO REDUCE WATER LOSS   8)  REPTILES WITH LIMBS HAVE BETTER BODY SUPPORT *MOST WALK WITH SPREAD LIMBS AND BELLY CLOSE TO THE GROUND 9) MORE COMPLEX NERVOUS SYSTEM  *THE FIRST TRUE CEREBRAL CORTEX IS PRESENT WHERE HIGHER THOUGHT PROCESSES TAKE PLACE  *JACOBSON’S ORGAN IS SPECIALIZED OLFACTORY STRUCTURE. THE TONGUE CARRIES ODORS TO THE ORGAN.  CLASSIFICATION OF REPTILES  ORDER TESTUDINES—TURTLES  ORDER SQUAMATA—SNAKES AND LIZARDS  ORDER SPHENODATA—TUATARA  ORDER CROCODILIA—CROCODILES AND ALLIGATORS  GENERAL CHARACTERISTICS  SPECIAL FEATURES OF BIRDS   1)  FEATHERS 2) SKELETON  * THE SKELETON OF A BIRD, FILLED WITH AIR CAVITIES, WEIGHS LESS THAN ALL OF ITS FEATHERS   3)  MUSCULAR SYSTEM 4) SPECIAL SENSES   5)  MIGRATION 6) SOCIAL BEHAVIOR AND REPRODUCTION   7)  DANGERS TO BIRD POPULATIONS MAJOR CHARACTERISTICS OF MAMMALS STRUCTURAL AND FUNCTIONAL ADAPTATIONS OF MAMMALS 1) INTEGUMENT AND ITS DERIVATIVES   2)  FOOD AND FEEDING 3) MIGRATION   4)  FLIGHT AND ECHOLOCATION 5) REPRODUCTION  CLASSIFICATION OF MAMMALS
 * THE FISHES **
 * CLASS MYXINI—HAGFISHES
 * CLASS PETROMYZONTES—LAMPREYS
 * MEMBERS OF BOTH OF THESE CLASSES LACK JAWS, BONES, SCALES, AND PAIRED FINS
 * MEMBERS OF BOTH CLASSES HAVE PORELIKE GILL OPENINGS AND AN EEL-LIKE BODY FORM
 * HEART WITH A SINGLE ATRIUM AND VENTRICLE
 * PRIMITIVE BONY FISH, SUCH AS THE GAR, HAVE HEAVY, DIAMOND-SHAPED SCALES CALLED GANOID SCALES
 * MODERN BONY FISHES, CALLED TELEOSTS, HAVE THINNER, MORE FLEXIBLE SCALES CALLED CYCLOID OR CTENOID SCALES
 * SWIM BLADDER AIDS IN BUOYANCY
 * SKELETON OF BONE
 * MEDIAN AND PAIRED FINS; TAIL FIN IS TYPICALLY HOMOCERCAL (WITH BOTH LOBES BASICALLY EQUAL)
 * MOST HAVE SCALES
 * RESPIRATION WITH GILLS
 * TWO-CHAMBERED HEART
 * LARGEST AND MOST DIVERSE GROUP OF ALL VERTEBRATES
 * FASTEST SPEED IS ABOUT 10 BODY LENGTHS PER SECOND, OR ABOUT 6.5 MPH
 * GENERALLY, LARGER FISH SWIM FASTER
 * SWORDFISH AND MARLIN ARE BELIEVED TO BE ABLE TO SWIM ABOUT 110KM PER HOUR (68 MPH) FOR SHORT PERIODS
 * SWIMMING USES LESS ENERGY IN CALORIES THAN ANY OTHER TYPE OF LOCOMOTION
 * SHARKS DO NOT HAVE A SWIM BLADDER AND MUST KEEP MOVING TO STAY AFLOAT: THEY ALSO HAVE A LIVER CONTAINING A VERY LOW DENSITY HYDROCARBON CALLED SQUALENE THAT HELPS KEEP THEM FROM SINKING
 * BONY FISH HAVE A SWIM BLADDER FILLED WITH GAS TO HELP THEM FLOAT
 * THE GAS IS MAINLY OXYGEN; BUT ALSO CONTAINS NITROGEN, CARBON DIOXIDE, ARGON, AND CARBON MONOXIDE
 * FISH TAKE WATER IN THROUGH THEIR MOUTHS, THE WATER FLOWS ACROSS THE GILLS AND EXITS THROUGH THE OPERCULUM THAT COVERS THE GILLS
 * THE BLOOD VESSELS OF THE GILLS REMOVE OXYGEN FROM THE WATER; SOME FISH CAN REMOVE AS MUCH AS 85% OF THE OXYGEN FROM THE WATER
 * FRESHWATER FISH HAVE A TENDENCY TO ABSORB WATER AND LOSE SALT, MAINLY THROUGH THEIR GILLS
 * THESE FISH PUMP WATER FROM THEIR BODIES THROUGH THE KIDNEYS AND HAVE SPECIAL SALT-ABSORBING CELLS IN THE GILLS THAT ABSORB SMALL AMOUNTS OF SALT FROM THE WATER
 * MARINE FISH HAVE THE OPPOSITE PROBLEM; THEY LOSE WATER AND GAIN SALT
 * THESE FISH ‘DRINK’ THE SALT WATER BUT HAVE SPECIAL SALT-SECRETORY CELLS IN THEIR GILLS TO REMOVE SALT
 * THE INTESTINES AND KIDNEYS REMOVE MOST OF THE REMAINING SALT FROM THE BLOOD
 * SPEND THEIR LIVES AT SEA, BUT RETURN TO FRESH WATER TO SPAWN
 * ATLANTIC SALMON SPAWN YEAR AFTER YEAR
 * PACIFIC SALMON SPAWN ONCE AND DIE
 * AFTER ABOUT 4 YEARS, PACIFIC SALMON RETURN TO THEIR PARENT STREAM TO SPAWN, LOCATING IT BY ITS CHARACTERISTIC ODOR
 * CLASS AMPHIBIA **
 * NO TAIL
 * SPECIALIZED FOR JUMPING
 * LARVAL STAGE (TADPOLE) HAS GILLS, A LONG TAIL, NO LEGS, AND IS A HERBIVORE
 * ADULTS ARE CARNIVORES AND BREATHE WITH LUNGS
 * ALMOST ALL ARE FOUND NEAR WATER
 * LARGEST FROG IS FOUND IN WEST AFRICA AND IS ABOUT 30 CM (1 FOOT) LONG; IT EATS ANIMALS AS LARGE AS RATS AND DUCKS
 * SMALLEST FROG IS LESS THAN 1 CM LONG AND IS FOUND IN BRAZIL
 * DURING BREEDING SEASON, VOCAL SOUNDS ARE USED TO ATTRACT A MATE
 * A POISON PRODUCED BY GLANDS IN THE SKIN IS IRRITATING TO PREDATORS
 * MOST HIBERNATE DURING WINTER IN MUD AT THE BOTTOM OF PONDS AND STREAMS
 * TERRESTRIAL FORMS HIBERNATE UNDERNEATH HUMUS ON THE FOREST FLOOR; SOME CAN SURVIVE IF 65% OF THEIR BODY WATER IS FROZEN
 * WHEN EGGS ARE READY TO BE RELEASED, THE MALE GRASPS THE FEMALE (A PROCESS CALLED AMPLEXUS) AND CAUSES HER TO LAY THE EGGS. HE RELEASES SPERM OVER THE EGGS TO FERTILIZE THEM.
 * CLASS REPTILIA **
 * CHARACTERISTICS OF REPTILES THAT DISTINGUISH THEM FROM AMPHIBIANS **
 * OFFERS PROTECTION AGAINST DRYING OUT (DESSICATION) AND PHYSICAL INJURY
 * THE SKIN HAS TWO LAYERS: THE EPIDERMIS, WHICH IS SHED FREQUENTLY, AND THE DERMIS, WHICH HAS CHROMATOPHORES (COLOR-BEARING CELLS) AND IS USED TO MAKE LEATHER
 * SCALES ARE A PART OF THE EPIDERMIS AND ARE FORMED OF KERATIN
 * HIGHER BLOOD PRESSURE
 * THREE-CHAMBERED HEART IN SNAKES, LIZARDS AND TURTLES
 * FOUR-CHAMBERED HEART IN CROCODILES AND ALLIGATORS
 * STILL ECTOTHERMIC
 * NO DIAPHRAGM
 * SUCK AIR INTO LUNGS BY EXPANDING THE PLEURAL CAVITY
 * ENCLOSED IN A SHELL WITH A DORSAL CARAPACE AND A VENTRAL PLASTRON
 * SHELL FUSED TO VERTEBRAE AND RIBS
 * BURY THEIR EGGS IN THE GROUND, THEN LEAVE THEM
 * IN SOME, NEST TEMPERATURE DETERMINES THE SEX OF THE HATCHLINGS
 * 95% OF ALL KNOWN LIVING REPTILES
 * “KINETIC” SKULL WITH MOVABLE JOINTS TO ALLOW EXCESSIVE JAW OPENING
 * PIT VIPERS HAVE HEAT-SENSITIVE PITS WHICH SENSE HEAT EMITTED BY BIRDS AND MAMMALS
 * SEEMS TO BE AN ANCIENT FORM OF REPTILE
 * CROCODILES ARE VERY AGGRESSIVE AND WILL EVEN ATTACK HUMANS
 * ALLIGATORS ARE LESS AGGRESSIVE
 * EGGS ARE EATEN BY SEVERAL TYPES OF MAMMALS AND YOUNG HATCHLINGS ARE EATEN BY LARGE FISH
 * FEMALES GUARD THE NEST; INCUBATION TEMPERATURE DETERMINES THE SEX OF THE YOUNG
 * CLASS AVES **
 * DISPROPORTIONATELY LONG NECK FOR BALANCE AND FOOD GATHERING
 * FORELIMBS NORMALLY MODIFIED FOR FLYING
 * FEATHERS AND LEG SCALES
 * SKELETON WITH AIR CAVITIES; BEAK, NO TEETH
 * FOUR-CHAMBERED HEART
 * ENDOTHERMIC
 * WELL-DEVELOPED ORGAN SYSTEMS
 * CONTOUR FEATHERS DEFINE THE SHAPE OF THE BIRD
 * DOWN FEATHERS WATERPROOF THE CHEST AND ABDOMEN OF WATER BIRDS, AND HELP CONSERVE HEAT IN OTHERS
 * MOST BIRDS SHED THEIR FEATHERS, OR MOLT, GRADUALLY—PENGUINS MOLT ALL AT ONCE
 * PECTORALIS MUSCLE, WHICH PULLS THE WINGS DOWN DURING FLIGHT, IS THE LARGEST
 * A TOE-LOCKING MECHANISM KEEPS A BIRD FROM FALLING OFF ITS PERCH WHEN ASLEEP
 * VISION IS EXCEPTIONAL—A HAWK CAN SEE A CROUCHING RABBIT MORE THAN A MILE AWAY
 * AN OWL CAN SEE IN DIM LIGHT 10 TIMES BETTER THAN A HUMAN
 * BIRDS HAVE GOOD COLOR VISION
 * MANY BIRDS MIGRATE NORTH TO SOUTH TO AVOID COLD WINTERS
 * MOST BIRDS BREED IN CANADA RATHER THAN IN MEXICO
 * FERTILIZATION IS INTERNAL
 * EGG INCUBATION, WHICH IS ACCOMPLISHED BY BOTH PARENTS, USUALLY LASTS 14-28 DAYS
 * VOCALIZATION AND COLORATION ARE IMPORTANT IN COURTSHIP
 * MALES ARE MORE COLORFUL THAN FEMALES, WHICH IS AN ADAPTATION FOR ATTRACTING A MATE
 * HUMAN ACTIVITIES SUCH AS BIRD HUNTING
 * AGRICULTURAL USE OF PESTICIDES, HERBICIDES, AND FERTILIZERS
 * HABITAT DESTRUCTION
 * CLASS MAMMALIA **
 * BODY COVERED WITH HAIR
 * INTEGUMENT (SKIN) WITH GLANDS: SWEAT GLANDS, OIL GLANDS, SCENT GLANDS
 * INTERNAL FERTILIZATION; EGGS DEVELOP IN A UTERUS WITH A PLACENTAL ATTACHMENT EXCEPT IN THE MONOTREMES
 * YOUNG NOURISHED BY MILK FROM MAMMARY GLANDS
 * THICKER SKIN THAN IN OTHER CLASSES OF VERTEBRATES
 * COVERED WITH HAIR IN ALL MAMMALS, YET THE HAIR CONSISTS OF ONLY A FEW SENSORY BRISTLES IN WHALES
 * A PROTEIN CALLED KERATIN HELPS TO FORM NAILS, CLAWS, AND HOOVES
 * HORNS ARE FOUND IN CUD-CHEWERS SUCH AS SHEEP AND CATTLE, CONSIST OF KERATIZED EPIDERMIS AND ARE NOT SHED
 * ANTLERS ARE FORMED ENTIRELY OF BONE AND ARE SHED YEARLY
 * THE RHINOCEROS HORN IS MADE OF HAIRLIKE KERATIN FILAMENTS
 * DURING MATING SEASON, THE SCENT GLANDS OF MANY MAMMALS GIVE OFF STRONG SCENTS TO ATTRACT A MATE
 * ALL NEWBORN MAMMALS ARE FED MILK FROM MAMMARY GLANDS
 * TOOTH TYPE IS AN INDICATION OF THE DIET OF MOST MAMMALS
 * THE LENGTH OF THE INTESTINE IS ALSO AN INDICATION OF DIET; A LONG INTESTINE IS PRESENT IN HERBIVORES
 * A FEW MAMMALS ARE KNOWN TO MIGRATE TO SUMMER OR WINTER BREEDING AND FEEDING GROUNDS
 * SEALS AND WHALES UNDERGO THE LONGEST MIGRATIONS
 * BATS, THE ONLY MAMMALS TO FLY, ONLY MIGRATE OCCASIONALLY
 * BATS ARE THE ONLY FLYING MAMMALS
 * THEY ARE NOCTURNAL AND TYPICALLY SPEND THE DAYLIGHT HOURS IN CAVES
 * THEY EMIT ULTRASONIC SOUNDS THAT HUMANS CANNOT HEAR TO AVOID HITTING OBJECTS OR TO LOCATE THEIR PREY
 * OTHER MAMMALS KNOWN TO USE ECHOLOCATION ARE INSECTIVORES (SHREWS) AND SOME WHALES
 * MONOTREMES ARE THE ONLY MAMMALS TO LAY EGGS
 * MARSUPIALS DEVELOP THEIR YOUNG WITH A PRIMITIVE PLACENTA, THEN CARRY THEM IN A POUCH UNTIL THEY ARE FULLY DEVELOPED
 * MOST MAMMALS CARRY THEIR YOUNG IN A UTERUS, WHERE THEY ARE ATTACHED TO A PLACENTA
 * ORDER MONOTREMATA—EGG-LAYING MAMMALS (DUCK-BILLED PLATYPUS AND SPINY ANTEATER)
 * ORDER MARSUPIALIA—POUCHED MAMMALS ( KANGAROO, KOALA, AND OPOSSUM)
 * ORDER INSECTIVORA—SHREWS AND MOLES
 * ORDER CHIROPTERA—BATS
 * ORDER PRIMATES—MONKEYS, APES, AND HUMANS
 * ORDER XENARTHRA—ANTEATERS AND ARMADILLOS
 * ORDER LAGOMORPHA—RABBITS
 * ORDER RODENTIA—GNAWING MAMMALS; SQUIRRELS, RATS, WOODCHUCKS
 * ORDER CETACEA—WHALES, DOLPHINS, PORPOISES
 * ORDER CARNIVORA—FLESH-EATING MAMMALS; DOGS, CATS, BEARS, WOLVES
 * ORDER PINNIPEDIA—SEA LIONS, SEALS, WALRUSES
 * ORDER PROBOSCIDEA—ELEPHANTS
 * ORDER SIRENIA—MANATEES
 * ORDER PERISSODACTYLA—ODD-TOED HOOFED MAMMALS; HORSES, DONKEYS, ZEBRAS, TAPIRS, RHINOCEROSES
 * ORDER ARTIODACTYLA—EVEN-TOED HOOFED MAMMALS; PIGS, CAMELS, DEER, HIPPOPOTAMUSES, ANTELOPES, CATTLE, SHEEP, GOATS