VERTEBRATES

YOU MUST KNOW…• THE FOUR CHORDATE

CHARACTERISTICS• TRAITS WHICH DISTINGUISH EACH OF

THE FOLLOWING GROUPS: CHONDRICHTHYES, OSTEICHTHYES, AMPHIBIA, REPTILIA, BIRDS, AND MAMMALIA

• ADAPTATIONS THAT ALLOWED ANIMALS TO MOVE ONTO LAND

• HOW THE THREE CLASSES OF MAMMALS DIFFER IN THEIR REPRODUCTION

CONCEPT 34.1• CHORDATES

HAVE A NOTOCHORD AND A DORSAL, HOLLOW NERVE CORD

• VERTEBRATES ARE MEMBERS OF THE PHYLUM CHORDATA

• 4 CHARACTERISTICS• NOTOCHORD – APPEARS DURING EMBRYONIC

DEVELOPMENT BETWEEN THE DIGESTIVE TUBE AND THE DORSAL NERVE CORD

• DORSAL, HOLLOW NERVE CORD – FORMED FROM A PLATE OF ECTODERM THAT ROLLS INTO A HOLLOW TUBE

• PHARYNGEAL CLEFTS – GROOVES THAT SEPARATE A SERIES OF POUCHES ALONG THE SIDES OF THE PHARYNX. THEY ALLOW WATER TO ENTER AND EXIT THE MOUTH WITHOUT GOING THROUGH THE DIGESTIVE TRACT

• A MUSCULAR TAIL POSTERIOR TO THE ANUS

CONCEPT 34.3• VERTEBRATES ARE CRANIATES

THAT HAVE A BACKBONE

LAMPREYS• OLDEST LINEAGE

OF VERTEBRATES, JAWLESS PARASITIC FISH WITH A SKELETON OF CARTILAGE

CONCEPT 34.4• GNATHOSTOMES

ARE VERTEBRATES THAT HAVE JAWS

• JAWS EVOLVED FROM MODIFICATION OF THE PHARYNGEAL (GILL) SLITS

• CLASS CHONDRICHTHYES – FLEXIBLE ENDOSKELETONS COMPOSED OF CARTILAGE, STREAMLINED BODIES, DENSER THAN WATER, WILL SINK IF THEY STOP SWIMMING – SHARKS AND RAYS

• CLASS OSTEICHTHYES – BONY FISHES, COVERED WITH SCALES, POSSESS A SWIM BLADDER – TROUT AND SALMON

CONCEPT 34.5• TETRAPODS ARE

GNATHOSTOMES THAT HAVE LIMBS AND FEET

• CLASS AMPHIBIA – INCLUDE FROGS, TOADS, SALAMANDERS, AND NEWTS

• GAS EXCHANGE CAN OCCUR ACROSS THEIR THIN, MOIST SKIN – MAY HAVE LUNGS

• MAY HAVE AQUATIC LARVAL STAGE WITH GILLS AND METAMORPHOSIS TO AN ADULT (FROGS)

• HAVE EXTERNAL FERTILIZATION AND EXTERNAL DEVELOPMENT IN AN AQUATIC ENVT (EGGS WITHOUT SHELL)

• AS LARVAE, AMPHIBIANS HAVE A TWO-CHAMBERED HEART (1,1). AS ADULT, THREE-CHAMBERED HEART (2,1).

CONCEPT 34.6• AMNIOTES ARE TETRAPODS

THAT HAVE A TERRESTRIALLY ADAPTED EGG

• AMNIOTES CONSIST OF MAMMALS AND REPTILES (ALSO BIRDS)

• AMNIOTIC EGG WAS IMPORTANT EVOLUTIONARY DEVELOPMENT FOR LIFE ON LAND

• EGGS HAVE SHELL THAT RETAINS WATER SO IT CAN BE LAID IN DRY ENVT

• EGG HAVE AMNION (FLUID), CHORION, ALLANTOIS, AND YOLK SAC (GAS EXCHANGE, WASTER STORAGE, AND TRANSFER OF STORED NUTRIENTS)

1. REPTILES – TURTLES, LIZARDS, SNAKES, ALLIGATORS, CROCODILES, EXTINCT DINOSAURS

• MODERN REPTILES HAVE SCALES CONTAINING KERATIN (REDUCE WATER LOSS)

• OBTAIN OXYGEN THROUGH LUNGS• ECTOTHERMIC (REGULATE TEMP

THROUGH BEHAVIORAL ADAPTATIONS RATHER THAN METABOLISM)

• INTERNAL FERTILIZATION AND AMNIOTE SHELLED EGG

• NITROGENOUS WASTE IS URIC ACID• HEART IS THREE-CHAMBERED (2,1)

2. BIRDS – WINGS, FEATHERS, ADAPTATIONS FOR FLIGHT

• LAY AMNIOTIC EGGS• HAVE KERATIN-CONTAINING SCALES ON

THEIR LEGS• LIGHT, HOLLOW BONES, FEWER ORGANS• FEATHERS AND A LAYER OF FAT

INSULATES BIRDS• FOUR-CHAMBERED HEART, HIGH

METABOLISM• ENDOTHERMS – MAINTAIN A WARM,

CONSISTENT BODY TEMP

CONCEPT 34.7• MAMMALS

ARE AMNIOTES THAT HAVE HAIR AND PRODUCE MILK

• MAMMALS POSSESS MAMMARY GLANDS

• HAVE A BODY COVERING OF HAIR• HAVE A FOUR-CHAMBERED HEART• ARE ENDOTHERMIC• INTERNAL FERTILIZATION, ARE BORN• PROPORTIONALLY LARGER BRAINS

THAN OTHER VERTEBRATES• ALL HAVE TEETH OF DIFFERING SIZE

AND SHAPE

1. MONOTREMES – EGG LAYING MAMMALS THAT HAVE HAIR AND PRODUCE MILK – PLATYPUSES, ANTEATERS

2. MARSUPIALS – BORN EARLY IN DEVELOPMENT AND COMPLETE EMBRYONIC DEVELOPMENT IN A POUCH WHILE NURSING – KARGAROO, OPOSSUM

3. PLACENTAL MAMMALS (EUTHERIANS) – LONGER PREGNANCY, COMPLETE THEIR DEVELOPMENT IN THE UTERUS – DOGS, HUMANS

• HUMANS BELONG TO THE ORDER PRIMATES ALONG WITH MONKEYS AND GORILLAS

• OPPOSABLE THUMBS, LARGE BRAINS AND SHORT JAWS, FORWARD-LOOKNG EYES, FLAT NAILS, WELL-DEVELOPED PARENTAL CARE, COMPLEX SOCIAL BEHAVIOR

• HUMANS – INCREASED BRAIN VOLUME, SHORTENING OF JAW, BIPEDAL POSTURE, REDUCED SIZE DIFFERENCE BETWEEN SEXES