Notochord

Supporting rod of connective tissue that runs the length of the dorsal side of the body

Subphyla of Chordata

1. Urochordata
2. Cephalochordata
3. Vertebrata

Urochordata

• Tunicates (sea squirts)
• Has Chordate characteristics in larval stage
• Adults are sessile, filter feeders

Cephalochordata

• Amphioxus (lancelet)
• Bottom dwellers
• Filter Feeders

Vertebrata - Characteristics

• Animals with backbones
• Internal segmentation (cavities)
• Eucoelom
• Endoskeleton jointed of bone and/or cartilage
• Spine (vertebrate)
• Girdles
• Ventrally located heart
• Red corpuscles (blood cells)
• Body plan - head, neck, trunk, tail
• Nerve cord is extension of brain

Oviparous

Egg laying

(ex: chickens)

Ovoviviparous

Eggs hatch inside body

(ex: shark)

Viviparous

Nourish young in cavity and give birth to live young

(ex: human)

Girdles

• two pairs of limbs attached to girdles
• pelvic is lower and pectoral is upper
• appendicular skeleton

Classes of Vertebrata

1. Agnatha (no jaws or appendages)
   
2. Chondrichthyes (skeleton of cartilage)
   
3. Osteichthyes (skeleton made of bone)
   
4. Amphibia (gill breathing larva, lung breathing adult)
   
5. Reptilia (reptiles, most live entire life on land)
   
6. Aves (most fly)
   
7. Mammalia (mammals)
   

Agnatha - Externals

• One nasal opening (for smell, not breathing)
• Two eyes
• Seven gill slits
• Mouth ring of cartilage, horny teeth, rasp like tongue
• Lateral line
• Anus
• Urogenital opening (liquid waste and reproductive cells exit)
• Slimy skin
• Single fins

Lateral line

sense organ for pressure of vibrations that runs the length of the body

Agnatha - Systems

• Skeletal: notochord, skeleton of cartilage
• Muscular: muscles around mouth help keep attached to fish
• Digestive: mouth, esophagus, intestine, anus, no stomach
• Circulatory: two chambered heart, cold-blooded, ectothermic
• Respiratory: seven pairs of gill slits lead to gills
• Nervous: primitive brain, dorsal nerve cord, olfactory sacs, pair of eyes, ten pairs of cranial nerves
• Endocrine: primitive
• Urogenital: kidney→urinary duct→urogenital sinus→opening
• Reproductive: gametes→coelom→two genital pores→sinus→opening

Class Chondrichthyes - Externals

• Three body regions
• Fusiform (torpeedo) shape
• Lateral line
• Placoid scales
• Rostrum (snout): two nares lead to olfactory lobes
• Mucus pores for lubrication
• Ampullae of Lorenzini
• Spiracles (modified gill slits)
• Paired Fins: dorsal, caudal, pectoral, pelvic
• Cloacal region: cloacal opening between pelvic fins, uninary papillae (small fleshy projections), and males have claspers

Placoid Scales

Circular shape with points that cause Chondrichthyes to have a sandpaper-like feeling to their skin

Ampullae of Lorenzini

• located on the top of the head, between the eyes
• detects electromagnetic fields

 Heterocercal and Homocercal

• When the two points of cadual fins are not symmetrical

[image]

Class Osteichthyes - Externals

• Lateral line
• Mouth, teeth, two eyes
• Nares for smell only
• Scales: ganoid, cycloid, ctenoid
• chomatophores: pigmented cell
• Body covered in mucus
• Paired fins: anal (keep upright), caudal (swim), pelvic (steer), pectoral (move up and down), dorsal

Class Osteichthyes - Systems

• Skeletal: skull, vertebra, ribs
• Digestive: mouth with teeth and tongue (for taste), pharynx, esophagus, stomach, intestine, anus, accessory organs (gall bladder, liver, pancreas)
• Circulatory: two chambered heart, red & white blood cells, ectothermic, cold blooded
• Respiratory: two gill chambers (four gills each), gill filaments, swim bladder to move up and down
• Excretory: kidneys→urinary bladder→urogenital opening
• Nervous: well developed brain, spinal cord, cranial nerves
• Reproduction: dioecious, oviparous, external fertilization

Special Characteristic of Amphibians

Metamorphosis: larval stage in water (tadpole) and adult stage on land

Order Apoda

• Part of Class Amphibia
• Without legs
• Caecilians

Order Urodela

• Part of Class Amphibia
• Visible tail
• Salamanders

Order Anura

• Part of Class Amphibia
• Without tail
• Frogs and toads

Class Amphibia - Externals

• Bulgy eyes an top of hear
• Nictitating membrane: third eyelid for protection underwater
• Typanic membrane: primitive ear
• External nares
• Mouth: two types of teeth (vomerine-top teeth, maxillary-outer edges)
• Openings: eustachian tube (to ear), gullet (opening of esophagus), glottis (opening to lungs)
• Sticky tongue
• Front forelimbs are not webbed
• Back hindlimbs are strong and webbed

Frog Mouth Diagram

Class Amphibia - Digestive System

• Extensile tongue
• Mouth
• Gullet leads to esophagus
• Stomach
• Small intestine: duodenum-straight part, ileum-coiled part (held together by mesentery)
• Large intestine
• Cloaca: collection sac (liquid/solid waste and reproductive cells)
• Accessory organs: pancreas, liver, gall bladder

Class Amphibia - Respiratory System

• Pulmonary respiration: nares, mouth, glottis leads to lungs, larynx, bronchi
• Cutaneous respration: ocurrs through skin, hibernation and estivation

Estivation

Similar to hibernation, but is in the summer because it is too hot

Class Amphibia - Excretory System

• Kidneys
• Urinary ducts
• Urinary bladder
• Cloaca
• Cloacal opening

Class Amphibia - Nervous System

• Brain
• Ten pairs of cranial nerves
• Spinal cord

Class Amphibia - Reproductive System

• Oviparous
• External fertilization in the water
• Male: testes→kidney→unrinary duct→bladder→ cloaca→cloacal opening
• Female: ovaries→oviduct→ovisacs→cloaca→cloacal opening

[image]

Class Amphibia - Circulatory System

• Three chambered hear in adults
• Two atria and one ventricle

• Ventricle: pumps oxygenated to body
• Atrium: receives deoxygenated blood from body

Class Amphibia - Interal Diagram

Amniotic Egg

• Amnion: thin fluid filled membrane that keeps the embryo moist
• Porous shell: keeps the egg from drying out
• Yolk sac: food supply
• Allantois: stores nitrogenous waste
• Chorion: regulates gas exchange
• Adaptation that allows eggs to be laid on land instead of in the water
• Makes reptiles more advanced than amphibians

Structure of the Amniotic Egg

Class Reptilia - Adaptations

• Amniotic egg
• Waterproof skin
• Limbs adapted for movement on land
• Partial separation of ventricle
• Excretory system conserves water
• Internal fertilization

Order Crocodilian

• Part of Class Reptilia
• Crocodiles: long and pointed snout
• Alligators: short and blunt snout

Order Squamata

• Part of Class Reptilia
• Covered with Scales
• Lizards

Order Rhynchocephalia

• Part of Class Reptilia
• Only animal in this order that is not extinct isthe tuatara (Sphendon)

Order Chelonia

• Part of Class Reptilia
• Shell: carapace (dorsal) and plastron (ventral)
• Turtles: live on land and in water
• Tortoises: live only on land

Snakes - a special lizard

• Jaws attached by ligaments
• No pectoral girdle
• No urinary bladder
• Scales
• Molt (shed skin)
• No appendages
• Eyelids are fused over eyes with transparent portion in the center
• No tympanic membrane
• Tongue is a sense organ (smell)
• Jacobson organ: roof of mouth, has chemosensory cells
• Teeth curved inward
• Toxins: hemotoxins (attack circulatory system) and neurotoxins (attack nervous system)

Snake Movement

• Rectilinear Movement
• Sidewinding Movement
• Lateral Undulation - most common

Archaeopteryx

• Link between reptiles and birds
• Characteristics of both classes
• Helped prove birds evolved during adaptive readiation from reptiles

[image]

Class Aves - Characteristics

• Classified by beaks, feet, plumage, bone structure, behavior and song
• Body covered with feathers
• Bone are thin and hallow
• Toothless horny beak (determine diet)
• Endothermic
• Warm blooded
• Four chambered heart
• Most forelimbs adapted for flight
• Hindlimbs are small ( determine diet)
• Oviparous
• Internal fertilization

Types of Beaks and Feet

• Beaks
• Seed eating (ex: finch)
• Meat eating (ex: eagle)
• Fish catcher (ex: pelican)

• Feet
• Scratching (ex: chicken)
• Grasping (ex: hawk)
• Perching (ex:finch)
• Swimming (ex: duck)

Types of Feathers

• Wings covered with feathers (modified scales)
• Types of feathers
• Down: cover and insulate body
• Contour: streamlined shape, colorization
• Flight feathers: wings, tail, specialized contour

Parts of a Feather

• Follicle: pits in skin
• Shaft: center
• Vanes: projections on either side
• Barbs: branch of vane
• Barbule: branch of barb that has hooks
• Preen: secretes oil

Diagram of a Feather

Class Aves - Externals

• Four body regions: head, neck, trunk, tail (rudder for brake and balance)

Class Aves - Digestive System

• Mouth
• Esophagus
• Crop: moistens food
• Gizzard: crushed food
• Intestine
• Cloaca
• Opening
• Accessory organs: pancreas, liver

Class Aves - Excretory System

• Kidneys
• Ureters
• Cloaca
• Uric acid

Class Aves - Respiratory System

• Nostrils
• Trachea
• Syrinx: song box
• Bronchii
• Lungs
• Air sacs: spaces in bones that reduce density

Class Aves - Circulatory System

• Four chambered heart
• right side received deoxygenated blood from body and pumps to lungs
• left side receives oxygenated blood from lungs and pumps to body

Class Aves - Nervous System

• Brain
• Spinal cord
• Senses
• color vision
• large eyes near side of head
• no external ear; ear canal opening to tympanic membrane
• less developed smell
• avoid bitter and toxic food by taste

Class Mammalia - Characteristics

• Endothermic
• Hair
• Four chambered heart
• Diaphragm aids in breathing
• Most species are viviparous
• Mammary gland secretes milk
• Four types of teeth: incisors (bite and cut), canines (grip, puncture, tear), bicuspids (teeth with two points that shear and shred), molars (grind and crush)

Order Monotremata

• Part of Class Mammalia
• Only egg laying mammals
• Oviparous
• Not completely endothermic
• Most primitive
• No teeth when mature
• Mother wraps body around eggs
• Pouch
• Leathery skin
• Great digging power
• Everything empties into cloaca
• Long, slender sticky tongue to catch insects
• Ex: platypus

Order Marsupialia

• Part of Class Mammalia
• Pouched called marsupium
• Mainly found in Australia
• Young are born premature
• Stay in pouch and feed for a period of time
• Ex: opossum, kangaroo, koala bear

Order Insectivora

• Part of Class Mammalia
• Insect- eating
• Nocturnal
• Most live underground
• Shrews are smallest mammals and have fastest metabolic rate
• Poison in saliva kills prey
• Ex: shrew, mole

Order Chiroptera

• Part of Class Mammalia
• Fly
• Live in caves
• Hind feet cling so they can hang upside down
• Good slight in darkness
• Echolocation: produce sound waves for direction
• Ex: bats

Order Edentata

• Part of Class Mammalia
• Toothless
• Sharp claws for digging
• Armored plates
• Roll into a ball for protection
• Ex: armadillos

Order Rodentia

• Part of Class Mammalia
• Gnawing mammals
• Chisel-like front teeth
• Spines usually lay flat, but elevatewhen alarmed
• Ex: porcupine, mice, rat, squirrel, beaver, groundhog

Order Carnivora

• Part of Class Mammalia
• Flesh-eating
• Canine teeth
• Most are digitigrades
• Highly developed brain
• Cats adapted to hunt and stalk
• Ex: bear, tiger, lion, hyena

Order Cetacea

• Part of Class Mammalia
• Largest living animals
• Blowholes
• Limbs modified into flippers
• Blubber
• Blue whale is the lasrgest animal
• Very well adapted for aquatic life
• Many becoming extinct
• Ex: whales, dolphins

Order Sirenia

• Part of Class Mammalia
• Heavy bones
• Broad teeth
• Limbs are flippers
• Live in Atlantic Ocean
• Ex: sea cow, manatees

Order Proboscidae

• Part of Class Mammalia
• Proboscus
• Largest land animal
• Loose skin
• Incisors are tusks
• Herbivorous
• African: large ears
• Indian: small ears
• Ex: elephant

Order Artiodactyla

• Part of Class Mammalia
• Hoofed
• Even-toed
• Some are Ruminants and chew their cud
• Horns or antlers usually on males
• Live in many different environments
• Ex: pig, hippo, cow

Order Perrisodactyla

• Part of Class Mammalia
• Hoofed
• Odd-toes
• Live in hers
• Stripes for camouflage
• Not all zebras are black and white
• Ex: zebra, rhino, tapir

Order Philodata

• Part of Class Mammalia
• Looks like a lizard
• Long snout and tongue
• Claws used to dig for insects
• Rolls into a ball for protection
• Eats ants and termites
• Ex: scaley anteater

Order Primates

• Part of Class Mammalia
• Long limbs
• Hand adapted for grasping with an opposable thumb
• Good sight and hearing
• Omnivores
• Ex: man, monkey, ape, lemur

Order Tubulidentata

• Part of Class Mammalia
• Tube teeth
• Long, sticky tongue
• Nocturnal
• Claws for digging
• Eats ants and termites
• Ex: aardvark

Order Hyracoidea

• Part of Class Mammalia
• Looks like a guinea pig
• Hoofed
• Nocturnal
• Herbivores and insect eating
• Ex: hyrax

Order Lagomorpha

• Part of Class Mammalia
• Long ears
• Developed hind legs
• Nests above ground
• Feed on plants
• Ex: rabbit, hare

Order Dermoptera

• Part of Class Mammalia
• Primitive
• Herbivore and insect eating; birds and fruit
• Harmless
• Nocturnal
• Membrane from ears to tail for flying
• Ex: flying lemur