CHORDATE CHARACTERISTICS DORSAL NERVE CORD NOTOCHORD AT SOME

CHORDATE CHARACTERISTICS • DORSAL NERVE CORD • NOTOCHORD AT SOME STAGE (STIFF FLEXIBLE ROD THAT SUPPORTS THE NERVE CORD) • PAIRED GILL SLITS AT SOME STAGE (CONNECTING PHARYNX TO OUTSIDE) • OTHER CHARACTERISICS: – TAIL EXTENDING BEYOND ANUS – BILATERAL SYMMETRY – THREE GERM LAYERS – COMPLETE DIGESTIVE TRACT – CLOSED CIRCULATORY SYSTEM

The Generalized Structure of a Chordate Section 30 -1 Notochord Muscle segments Tail Anus Hollow nerve cord Mouth Pharyngeal pouches

Chordate Cladogram Section 30 -1 Birds Amphibians Fishes Nonvertebrate chordates Invertebrate ancestor Reptiles Mammals

CHORDATE CLASSIFICATION (BASED ON COMPARISON OF YOUNG WITH ADULTS) • SUBPHYLUM UROCHORDATA ADULTS NO DORSAL NERVE CORD, NOTOCHORD, OR GILL SLITS • SUBPHYLUM CEPHALOCHORDATA ADULTS- HAVE NOTOCHORD, DORSAL NERVE CORD, & GILL SLITS • SYBPHYLUM VERTEBRATA ADULTS- HAVE DORSAL NERVE CORD, BUT NO NOTOCHORD OR GILL SLITS

Vertebrate Characteristics • • • Endoskeleton for support, protection, muscle attachment Bone or cartilage replaces notochord Enlarged brain case (cranium) with spinal cord that is surrounded by bones (vertebrae) Definite body form- head, neck, trunk, tail Body covering- (skin, scales, feathers, hair) may be replaced by shedding or molting

Vertebrate Characteristics Cont. • Endoskeleton divided into 2 major divisions: 1. Axial skeleton: made up of the skull and spine 2. Appendicular skeleton: limb attachments to the girdles, limbs are in pairs (fins, legs, wings, flippers) • Pectoral girdle: anterior end, shoulder region • Pelvic girdle: posterior end, hip region

Vertebrate Characteristics Cont. • Respiration (gas exchange)/ moist skin, gills, lungs • Excretion (wastes from blood)/ moist skin, gills, lungs • Endocrine glands secrete hormones to regulate body processes • Body temperature- warmer body temperature, greater metabolic rate a. Cold-blooded (exothermic) varies according to temperature of surrounding environment b. Warm-blooded (endothermic) remains constant in spite of surrounding environment

Vertebrate Characteristics Cont. • • Larger, more specialized muscles (more speed, dexterity, agility, strength) Different patterns of egg development (food supply for developing young) Oviparous, ovoviviparous, and viviparous Portuguese shark

Vertebrate Characteristics Cont. • More efficient heart for pumping blood, increase in number of chambers, no mixing of oxygenated and deoxygenated blood Fish (2), amphibians (3), reptiles (3 ½ or 3), birds & mammals (4) Single-Loop Circulatory System FISHES Double-Loop Circulatory System MOST REPTILES CROCODILIANS, BIRDS, AND MAMMALS

Vertebrate Characteristics Cont. • Larger cerebrum (brain)- behavior is more complex Inborn: inherited (instincts, reflexes) Learned: acquired (memory, intelligence, skills, problem solving)

VERTEBRATE TRENDS 1. REGULATION OF BODY TEMPERATURE - FROM EXOTHERMIC (FISH, AMPHIBIANS, REPTILES) TO ENDOTHERMIC (BIRDS, MAMMALS). - THREE FACTORS INVOLVED: A) SOURCE OF HEAT FOR THE BODY; BEHAVIOR (FROM ENVIRONMENT) & METABOLIC ACTIVITY B) WAY TO CONSERVE BODY HEAT: FAT, FEATHERS, AND HIBERNATION C) ELIMINATES EXCESS HEAT WHEN NECESSARY: SHADE, MUD, WATER, ESTIVAYTION, SWEATING, PANTING 2. FEEDING - KINDS OF TEETH & JAWS - CROPS, GIZZARDS, STOMACHS. EXTRA PARTS: LIVER, PANCREAS, GALL BLADDER - INTESTINE LENGTH RELATED TO KIND OF DIET – LONGER IN HERBIVORES - CELLULOSE DIGESTION FERMENTERS, HERBIVORES

VERTEBRATE TRENDS CONT. 2. FEEDING - KINDS OF TEETH & JAWS - CROPS, GIZZARDS, STOMACHS. EXTRA PARTS: LIVER, PANCREAS, GALL BLADDER - INTESTINE LENGTH RELATED TO KIND OF DIET – LONGER IN HERBIVORES - CELLULOSE DIGESTION FERMENTERS, HERBIVORES

Overview of Digestive Systems of Vertebrates Section 33 -3 Esophagus Stomach Intestine Liver Gallbladder Pancreas Cloaca Crop Gizzard Cecum Rectum Shark Salamander Lizard Pigeon Cow

VERTEBRATE TRENDS CONT. 3. GAS EXCHANGE - GILLS FISH, YOUNG AMPHIBIANS - LUNGS ADULT AMPHIBIANS (WITH MUCOUS-COATED SKIN!), REPTILES, BIRDS, MAMMALS BIRDS HAVE THE MOST EFFICIENT SYSTEM (FRESH AIR FLOWS IN ONE DIRECTION, NO MIXING OF NEW/USED AIR)

Overview of Vertebrate Lungs Section 33 -3 Nostrils, mouth, and throat Trachea Lung Air sac Salamander Lizard Primate Pigeon

VERTEBRATE TRENDS CONT. 4. NERVOUS/RESPONSE - INCREASED CEPHALIZATION BRAIN INCREASES IN SIZE - SIZE & COMPLEXITY OF CEREBRUM (SENSORY INFORMATION & INSIGHT) & CEREBELLUM (BALANCE & COORDINATION) INCREASES - FISH HAVE LATERAL LINE TO DETECT VIBRATIONS & PRESSURE CHANGES

VERTEBRATE TRENDS CONT. 5. CIRCULATION/TRANSPORT - SINGLE LOOP (FISH) HEART, GILLS, BODY - DOUBLE LOOP (ALL OTHER VERTEBRATES) HEART, LUNGS, HEART, BODY, HEART… - HEART DEVELOPS CHAMBERS & VALVES THAT PERMIT ONE-WAY FLOW OF BLOOD WITH NO MIXING OF OXYGEN RICH & OXYGEN POOR BLOOD - NUMBER OF CHAMBERS INCREASE AS ENDOTHERMY INCREASES: - FISH (2) AMPHIBIANS (3) REPTILES (3½ -4) BIRDS & MAMMALS (4)

VERTEBRATE TRENDS CONT. 6. EXCRETION (RESPONSIBLE FOR WATER LOSS!) - REMOVAL OF NITROGEN WASTES FROM BLOOD - REGULATIONS OF AMOUNT OF BODY WATER: FISH (GILLS), ALL OTHERS (KIDNEYS-REABSORB USEFUL SELECTIVE SUBSTANCES) - NEPHRONS ARE THE STRUCTURAL UNITS OF THE KIDNEY (NUMEROUS!) - NITROGEN CONTAINING WASTES: AMMONIA – HIGHLY TOXIC, REQUIRES THE MOST WATER (FISH) - UREA- AMPHIBIANS, MAMMALS; STORED IN URINARY BLADDER; REQUIRES LITTLE WATER - URIC ACID- BIRDS (FLIGHT) & REPTILES (HOT AREAS) ; REQUIRES NO WATER *FORM OF NITROGEN WASTE BASED ON ENVIRONMENT

VERTEBRATE TRENDS CONT. 7. REPRODUCTION - MOST VERTEBRATES REPRODUCE SEXUALLY. - TREND FROM EXTERNAL TO INTERNAL FERTILIZATION; EXTERNAL TO INTERNAL DEVELOPMENT; MANY EGGS TO FEWER EGGS AND NO PARENTAL CARE TO MUCH PARENTAL CARE. - 3 PATTERNS OF EGG DEVELOPMENT: a. OVIPAROUS: EGG OUTSIDE FEMALE, FOOD FROM YOLK MONOTREMES, BIRDS, MOST FISH, REPTILES, & AMPHIBIANS b. OVOVIVIPAROUS : EGG INSIDE FEMALE, FOOD FROM YOLK MANY SNAKES, SOME FISH, SOME SHARKS c. VIVIPAROUS: EGG INSIDE FEMALE, FOOD FROM MOTHER MOST MAMMALS, SOME SHARKS

FISH – (ICHTHYOLOGY) CLASS AGNATHA (JAWLESS FISH) LAMPREY HAGFISH

CLASS CHONDRICHTHYES (CARTILAGINOUS FISH) SHARKS, SKATES, RAYS *only chondrichthyes & marine invertebrates are ISOTONIC with their marine environment

CLASS OSTEICHTHYES (BONY FISH) PERCH, TUNA, BASS, TROUT…

FISH CHARACTERISTICS 1. 2. 3. 4. SCALES- 2 KINDS (CATFISH HAVE NONE) a) PLACOID (TOOTHLIKE) OR b) CYCLOID (OVERLAPPING), MUCUS, CHROMOATOPHORES, COUNTERSHADING BONY FISH HAVE SWIM (AIR) BLADDER- ENABLES FISH TO REMAIN BUOYANT IN WATER, NO SWIM BLADDER SHARKS HAVE FINS SUPPORTED BY CARTILAGE; - ONLY BONY FISH THAT DO NOT HAVE RAY FINS ARE THE LUNGFISHES & COELANTHS- THEY HAVE FLESHY LIMB-LIKE FINS (CAN PROVIDE SPPORT & CAN WALK ON BOTTOM) FINS OF RAYS OR SPINES SPECIAL SENSE ORGAN ON SIDES OF BODY CALLED LATERAL LINES ON SIDE OF BODY- SENSITIVE TO PRESSURE CHANGES & VIBRATIONS IN H 2 O; “WHISKERS” ON CATFISH DO TOO.

FISH CHARACTERISTICS CONT. 5. BONY FISH HAVE ONLY 1 GILL OPENING COVERED BY THE OPERCULUM (4 PR. OF GILLS INSIDE); SHARKS HAVE SEPARATE OPENINGS/SLITS FOR EACH GILL 6. REPRODUCTION – EXTERNAL FERTILIZATION & DEVELOPMENT IN MOST FISH. MALES RELEASE SPERM (MILT) & FEMALES RELEASE EGGS (SPAWN) AT NEARLY SAME TIME! 7. DEVELOPMENT OF EGG – OVIPAROUS, OVOVIVIPAROUS, OR VIVIPAROUS 8. TWO-CHAMBERED HEART & COLD BLOODED – ALL!! *FIRST ANIMALS TO EVOLVE KIDNEYS – FRESHWATER FISH

Circulation in a Fish – SINGLE LOOP CIRCULATORY SYSTEM Section 30 -2 Gills Body muscle circulation Digestive system circulation Heart Oxygen-rich blood Oxygen-poor blood Brain and head circulation Sinus Venosus Oxygen-poor blood from the veins collects in the sinus venosus. Ventricle The ventricle pumps blood into the bulbus arteriosus. Atrium Blood enters the atrium and flows to the ventricle. Bulbus Arteriosus The bulbus arteriosus moves blood into the ventral aorta and toward the gills.

COUNTERCURRENT FLOW MECHANISM: MECH. FOR TRANSFER OF O 2 FROM H 2 O TO GILLS. CONCENTRATION GRADIENT ENHANCES DIFFUSION.

The blood in the capillaries flow in the opposite direction to the flow of water. This is called countercurrent system. This ensures maximum intake of oxygen (80%) by the blood. This is because the blood in the capillaries always encounter water that has greater concentration of oxygen. This creates a concentration gradient for a longer time so that oxygen can diffuse easily into the blood vessel from water.

The Anatomy of a Fish Section 30 -2 Kidney Pyloric cecum Stomach Vertebra Muscle Esophagus Swim bladder Spinal Gills cord Brain Mouth Operculum Urinary bladder Heart Anus Reproductive organ Pancreas Intestine Gallbladder Liver

CLASS AMPHIBIA “DOUBLE LIFE” BOTH H 2 O & LAND 1. 2. 3. 4. 5. 6. 7. 8. SKIN USUALLY THIN & MOIST (GAS EXCHANGE!) EARLIEST TETRAPODS (4 FOOTED) LAND VERTEBRATES! FEET USUALLY WEBBED; CLAWLESS TOES 3 -CHAMBERED HEART; COLD BLOODED RESP. BY GILLS, MOIST THIN SKIN, AND LUNGS HAVE NICTITATING MEMBRANE- 3 RD LAYER COVERING EYE (IN ADDITION TO EYELID) OVIPAROUS, OVOVIVIPAROUS, OR VIVIPAROUS TEMP/MOISTURE PROTECTION – HIBERNATION IN THE WINTER & ESTIVATION- WHEN HOT & DRY

• Red eyed tree frog resting seemingly with its eyes closed, as it watches through its third eyelid, a transparent membrane also called the nictitating membrane. Isolated on white

Amphibians 3 -Chambered Heart

AMPHIBIANS Section 30 -3 Amphibians means “Double life” as larvæ they live in adults they live on Water Land have special adaptations such as Bones that allow for Efficient movement Lungs are Ribs that allow that provide Breathing are air Support and protection

The Life Cycle of a Frog Section 30 -3 Adult Frog Young Frog Adults are typically ready to breed in about one to two years. Frog eggs are laid in water and undergo external fertilization. Fertilized Eggs The eggs hatch into tadpoles a few days to several weeks later. Tadpoles gradually grow limbs, lose their tails and gills, and become meat-eaters as they develop into terrestrial adults.

CLASS REPTILIA (HERPETOLOGY) “CREEPING ANIMALS” (Shelled eggs allowed for life on land- leathery and flexible!!!)

REPTILE CHARACTERISTICS 1. 2. 3. 4. BODY COVERED WITH THICK, DRY SCALES (LIFE ON LAND!) - 1 ST GROUP OF VERTEBRATES HAVING SKIN ADAPTED FOR LIFE ON LAND! - SHEDDING (MOLTING OCCURS IN SOME- MODS OF SCALESSCUTES (SNAKES) BOTTOM SCALES THICKER; CARAPACE (TURTLES) UPPER SHELL FUSED TO VERTEBRAE; AND PLASTRON (TURTLES) LOWER SHELL LIMBS, IF PRESENT, HAVE CLAWS OR TOES (LIZARD), PADDLE LIKE FOR SWIMMING (TURTLES), OR ABSENT (SNAKE). MOST HAVE A 3½ CHAMBER HEART (ONE VENTRICLE INCOMPLETE SEPTUM) RESPIRATION BY LUNGS ONLY; EXOTHERMIC

5. 6. REPTILE CHARS CONT. REPRODUCTION– INTERNAL FERTILIZATION; EGG DEV MAY BE OVIPAROUS (TURTLES & SNAKES) OR OVOVIVIPAROUS (SOME SNAKES & LIZARDS); MOST HAVE EXTERNAL DEVELOPMENT; SOME HAVE PARENTAL CARE (ALLIGATORS, SOME SNAKES) SENSORY ORGANS– NO MOVEABLE EYELID, HAVE PROTECTIVE COVERING OVER EYE; - GOOD SENSE OF SMELL- USE TONGUE TO SENSE AIR AND SIGNAL JACOBSON’S ORGAN (IN ROOF OF SNAKE MOUTH) TO SENSE CHEM. SIGNALS IN AIR - HEAT SENSORS IN SKIN (PITS) CAN DETECT WARM BLOODED ORGANISMS (PREY!!) - “THIRD EYE” (PINEAL GLAND) OF TUATARAS IS LIGHT SENSITIVE ORGAN

The Amniotic Egg The amnion is a fluid-filled sac Section 31 -1 that surrounds and cushions the developing embryo. It produces a protected, watery environment. The allantois stores the waste produced by the embryo. It also serves as a respiratory organ. Allantois Embryo Amnion The chorion regulates Chorion the transport of oxygen from the surface of the egg to the embryo and the transport of carbon dioxide, one product of respiration, in the opposite direction. Yolk sac This baglike structure contains a yolk that serves as a nutrient-rich food supply for the embryo. 7. Shell PRODUCE AMNIOTIC EGGS – KEY ADAPTATION FOR LIFE ON LAND (EMBRYO SURROUNDED BY MEMBRANES AND A SHELL). - SHELL (PROTECTION & PREVENTION OF H 2 O LOSS ) AMNION (SURROUNDS EMBRYO, FILLED W/ FLUID) YOLK (FOOD SUPPLY) ALLANTOIS (COLLECTS DIGESTIVE WASTES) CHORION (JUST UNDER SHELL – PROTECTION)

The Structure of a Turtle’s Heart Section 31 -1 Liver Kidney Heart Cloaca Bladder Lung Digestive tract To body To lungs From body Ventricle Right atrium From lungs Left atrium Incomplete division

CLASS AVES (ORNITHOLOGY) FEATHERS! (evolved from reptiles

BIRDS Section 31 -2 Birds have the following adaptations to flight Wings Feathers Strong chest muscles Efficient respiratory system Efficient circulatory system which are that also that power that provide that ensure Homologous to front limbs in other vertebrates Provide warmth Upward and downward wing strokes One-way flow of O 2 -rich air O 2 distribution to body tissues

BIRD CHARACTERISTICS 1. 2. 3. 4. SKIN COVERED WITH FEATHERS. 2 PRS. OF LIMBS – ANTERIOR PAIR=WINGS; POSTERIOR PAIR = FEET (PERCHING, WALKING, SWIMMING); FEET USUALLY HAVE 4 TOES SKELETON – BONES ARE HOLLOW(AIR SPACES); HAVE LARGE STERNUM (BREASTBONE) FOR WING MUSCLES. WARM BLOODED; 4 CHAMBERED HEART

BIRD CHARACTERISTICS 5. 6. 7. 8. 9. HIGHLY DEVELOPED SENSE OF “VOICE” (SYRINX) “SONG BOX”, HEARING, SIGHT, BALANCE, & COORDINATION HIGH METABOLIC RATE – USE A LOT OF ENERGY, EAT A LOT. NO URINARY BLADDER (NO LIQUID WASTE – SEMI SOLID) NO TEETH – HAVE GIZZARD FOR GRINDING FOOD; MODIFICATIONS OF BEAK STRUCTURE ENABLE BIRDS TO HAVE VARIED DIETS. FEATHERS – CONTOUR (COVER BODY & WINGS); NEED CARE (PREENING); HAVE COLORS (PLUMAGE); DOWN FEATHERS (CLOSE TO SKIN, FLUFFY, INSULATION); OIL GLAND AT BASE OF TAIL USED FOR PREENING (SMOOTHING & WATERPROOFING).

BIRD CHARS CONT. 10. USE OF ENERGY REQUIRES MUCH OXYGEN. LUNGS HAVE EXTENSIONS CALLED AIR SACS THAT EXTEND INTO BODY SPACES & INTO HOLLOW BONES. AIR SACS INCREASE SURFACE AREA, AND ALLOW. ONE WAY AIR FLOW! MOST EFFICIENT TERRESTRIAL RESP. SYSTEM!! AVIAN TWO-CYCLE PUMP

Birds 2 -Cycle Process • • • 8 or 9 extensions of the lungs (air sacs) act as bellows that temporarily store air and then contract to force air through the system. This moves fresh air through the lungs when birds are inhaling, and also when they're exhaling. - On inhalation, both sets of air sacs inflate. Inhaled air flows down the trachea, bypasses the lungs, and fills up the posterior air sacs (b). At the same time, the anterior air sacs fill with stale air from the lungs (d). - On exhalation, both sets of air sacs deflate, forcing fresh air from the posterior sacs into the lungs (c), and stale air from the anterior sacs out through the trachea (e). Air takes two cycles of inhalation and exhalation to pass through the system and out of the bird.

AVIAN AIR FLOW TRACHEA (INHALATION) POSTERIOR AIR SACS (1/2) EXHALE LUNG *O ABSORBED (1/2) 2 ANTERIOR AIR SACS *O 2 ABSORBED EXHALE TRACHEA (OUT)

BIRD CHARS CONT. 11. AMNIOTIC EGG COVERED WITH LIME SHELL; INTERNAL FERTILIZATION & EXTERNAL DEVELOPMENT (OVIPAROUS); SOME YOUNG ARE HELPLESS AT BIRTH, OTHERS CAN CARE FOR SELVES

CLASS MAMMALIA (evolved from reptilesearlier in history than birds)

MAMMAL CHARACTERISTICS 1. Skin covered with hair or fur with layer of fat underneath; may contain glands- sweat, tear, scent, sebaceous (oil), and mammary 2. All are endothermic- generate their own body heat by metabolism; must conserve heat of environment (harsh), yet must remove excess heat at other times 3. Some are oviparous (platypus, spiny anteater); most are viviparous- nourished by mother before birth (placenta) and after birth (mammary glands)

MAMMAL CHARS CONT. 4. Lung breathers- have a diaphragm- a muscular sheet separating the thorax and abdomen that is used for breathing along with rib muscles

MAMMAL CHARS CONT. 5. Four chambered heart- 2 loops- one goes to and from the lungs while the other goes to and from the body- more efficient- no mixing of O 2 rich and O 2 poor blood- RBCs w/o nuclei

MAMMAL CHARS CONT. 6. Moveable tongues& eyelids, and external fleshy ears 7. Teeth vary- canines, incisors, and molars, for heterotrophic nutrition/ carnivores, herbivores, omnivores (scavengers, predators, vampires, ruminants, and filter feeders) 8. 2 pair of limbs- adapted for running, swimming, flying, grasping, climbing, walking, digging, burrowing- each foot has 5 toes w/ claws, nails, hooves, or fleshy pads Canines are pointed teeth. Carnivores use them for piercing, gripping, and tearing. In herbivores, they are reduced or absent. Chisel-like incisors are used for cutting, gnawing, and grooming. Molars crush and grind food. The ridged shape of the wolf’s molars and premolars allows them to interlock during chewing, like the blades of scissors. The broad, flattened molars and premolars of horses are adapted for grinding tough plants.

MAMMAL CHARS CONT. 9. Well developed kidneys that regulate the composition of body fluids- remove urea, remove or retain water, salts, and sugars- have urinary bladders w/ fluid excretion (urine) 10. Highly developed brain- cerebrum (learning and memory), cerebellum (coordination & balance) and medulla (internal regulation) 11. Usually 7 vertebrae in neck, 3 bones in ear 12. Testes usually external, fertilization internal- females have repro cycles (estrus/ menstrual) and gestation periods (pregnancy), internal development- parents usually care for young until adulthood 13. 3 subclasses (based on method repro)monotremes, marsupials, placentals

MONOTREMES • EXTERNAL AMNIOTE EGGS WITH SHELLS • NO VAGINA OR UTERUS • NO NIPPLES – GLANDS OPEN ONTO SKIN • ADULTS HAVE BILLS (NOT LIPS) • EX. PLATYPUS SPINY ANTEATER (ECHIDNA)

MARSUPIALS • VENTRAL ABDOMINAL POUCH • YOUNG BORN UNDEVELOPED – MUST COMPLETE DEVELOPMENT IN POUCH • NIPPLES INSIDE POUCH • DOUBLE UTERUS & TWO VAGINA – SEPARATE OPENINGS

PLACENTALS • SEPARATE URINARY & VAGINAL OPENINGS • FLUIDS FROM TESTES & BLADDER REACH OUTSIDE THROUGH COMMON OPENING AT TIP OF PENIS • DOUBLE OR SINGLE UTERUS, BUT ALWAYS SINGLE VAGINA • FETUS ATTACHED TO & NOURISHED BY PLACENTA DURING DEVELOPMENT • PLACENTA IS THE CONNECTION BETWEEN MOTHER & EMBRYO. IT IS FORMED FROM EMBRYONIC & UTERINE TISSUE.

Section 33 -1 Cladogram of Chordates Nonvertebrate chordates Jawless fishes Cartilaginous fishes Bony fishes Amphibians Reptiles Birds Mammals

Diversity of Chordates

Temperature Control in Chordates Body Temperature (°C) Section 33 -2 Environmental Temperature (°C)

Overview of The Circulatory Systems Section 33 -3 of Vertebrates Single-Loop Circulatory System FISHES Double-Loop Circulatory System MOST REPTILES CROCODILIANS, BIRDS, AND MAMMALS

Section 33 -3 Comparing Functions of Chordates Function Nonvertebrate Chordates Fishes Amphibians (adult) Respiration Gills and diffusion Gills/air sacs Simple lungs Lungs and skin Circulation No true chambers Single loop; 2 Double loop; 3 Double loop; 4 chambers chambers Excretion Gills and gill slits Kidney and gills Response Simple; mass Cephalization; Cephalization; of nerve cells small large cerebrum cerebrum Kidney and gills Reptiles Kidney Birds Mammals Lungs (tubes Lungs and air sacs; (alveoli) one-way flow) Kidney

Section 33 -3 Comparing Functions of Chordates Function Movement Nonvertebrate Chordates Muscles, no bones Reproduction External fertilization Temperature Ectothermic Control Fishes Amphibians (adult) Muscles on Limbs stick either side of out sideways; backbone muscles and ligaments External fertilization Reptiles Birds Limbs point Upper limbs directly toward are wings; 2 ground; feet; muscles and ligaments 2 or 4 legs; walk with legs straight under them; muscles and ligaments Internal fertilization; shelled egg Internal fertilization and development Internal fertilization; shelled egg Ectothermic Mammals Endothermic

Section 32 -2 Orders of Placental Mammals Order Characteristics Examples Insectivores Long, narrow snouts, sharp claws Shrews, hedgehogs, moles Sirenians Water-dwelling, slow-moving Manatees, dugongs Cetaceans Live and breed in ocean, come to Whales, dolphins surface to breathe Chiropterans Winged, capable of true flight Rodents Single pair of long, curved incisor Mice, rats, voles, squirrels, beavers, teeth in upper and lower jaws porcupines, chinchillas Bats

Section 32 -2 Orders of Placental Mammals Order Characteristics Examples Perissodactyls Hoofed, with an odd number of toes on each foot Horses, tapirs, rhinoceroses, zebras Carnivores Sharp teeth and claws Tigers, hyenas, dogs, foxes, bears, raccoons, walruses Artiodactyls Hoofed, with an even number of toes on each foot Cattle, sheep, goats, pigs, ibex, giraffes, hippopotami, camels Proboscideans Trunks Asian and African elephants, mastodons and mammoths

Section 32 -2 Orders of Placental Mammals Order Characteristics Examples Lagomorphs Two pairs of incisors in upper jaw, hind legs allow leaping Snowshoe hares, rabbits Xenarthrans No teeth (or very small teeth in the back of the jaw) Sloths, anteaters, armadillos Primates Highly developed cerebrum and complex behaviors Lemurs, tarsiers, apes, gibbons, macaques, humans