VERTEBRATES

CHORDATA Have a notochord( replaced in human by backbone) Pharyngeal Pouches- become gills or lungs Post –anal tail-disappears in us Dorsal hollow nerve chord- becomes the spinal chord

Fish

3 Types Agnatha- Jawless- Lamprey and hagfish Chondrichthyes- cartilage fish- sharks, rays,and skates Osteichthyes- Boney fish- majority

Fish Characteristics Have gills- water passes over gills. The oxygen in the water is exchanged for the carbon dioxide in the gills. This is called COUNTER CURRENT EXCHANGE.

2 chambered heart Sexual reproduction –most external fertilization- called spawning Some have internal fertilization like sharks Paired fins Scales- thin boney plates Swim Bladder- fills with oxygen or nitrogen to control swimming depth

Sensory system called LATERAL LINE SYSTEM- detects changes in environment. Found in Chondrichthyes and Osteichthyes.

AMPHIBIANS Salamanders, frogs, toads, legless caecillans Thin moist skin- helps to absorb oxygen from air Need water for fertilization to occur- sperm needs to swim to egg. External fertilization Ectotherm- body temperature varies according to environmental temperature Frogs and toads secrete chemical so they are bad tasting so predator won’t eat them Frogs have vocal chords to communicate

Metamorphosis Go through intermediate stage before becoming adult Egg → Tadpole → FROG fins legs gills lungs 2 chambered ♥ 3 chambered ♥

Reptiles Crocodiles, Alligators, Snakes Scaly skin- prevents water loss Reproduce on land- Internal Fertilization Produce EGGS- covered in leathery material. Amniotic egg- provides nourishment for embryo Legs are directly under body for speed

Some have 3 chambered hearts, most have 4 Ectotherms Nutrition- some are herbivores, predators or carnivores. Obtain prey by catching, constriction, or poisoning

Jacobson’s organ- sense organ. Snake sticks out their tongue and collects air molecules. Draws tongue into pit in mouth and senses what is there.

BIRDS Feathers- Wings made of protein- provides insulation and enables flight. Molting- new growth Loss of wing and tail feathers occur in pairs- balance for flight Attached to breast bone called a sternum Hollow bones- have air spaces- enables flight

Circulatory/Respiratrory System Birds require a lot of energy for flight Have a 4 chambered heart High heart beat- chickadee- 500/min human- 70/min Oxygen supplied during inhalation and exhalation

Endotherm- maintain constant body temperature Internal Fertilization- have an amniotic egg with a hard shell. Birds make nests and incubate their eggs until hatched Adaptations- beak shape and size according to food source

Mammals Endotherm- maintain constant body temperature

7 CHARACTERISTICS OF MAMMALS Hair- made of keratin- provides insulation Produce milk for nourishment of young through mammary glands Diaphragm- muscle that helps enlarge chest cavity for air intake

4. 4 chambered heart- oxygenated and de-oxygenated blood do not mix- most efficient 5. Specialized teeth- adapted to what they eat- pointed incisors- grasping canines- puncture molars- grinding

6. Modified limbs- used for food gathering, opposable thumb 7. Developed Brain- able to teach their young, remember what they learn Chimps use tools Brain- has many grooves to increase active surface area.

Mammalian Diversity-based on reproductive method Placental (90%)-fetus develops in uterus. Nourished through placenta. Gestation (how long in uterus varies) Marsupial- embryo spends short time in mom then develops in pouch(Kangaroo, Koalas) Monotreme- Egg layer like duck billed platypus and spiny anteater