Biology Notes: Unit 8“Exploring The Vertebrates”

A. Characteristics of Vertebrates◦ 1. Have a vertebral column

◦ 2. Most have 2 sets of appendages

◦ 3. Closed circulatory system

◦ 4. Gills or lungs for breathing

I. Vertebrates-animals with a backbone.

II. Vertebrates Body Systems◦ A. Endoskeleton-an internal skeleton◦ B. Body temperature regulation

1. Ectothermic- “cold-blooded”-body temperature changes with the environment. i.e. fish, amphibians, reptiles

2. Endothermic- “warm-blooded”-maintain a constant body temperature by internal regulation. i.e. birds and mammals.

C. Reproduction-sexual◦ 1. External fertilization-must reproduce in water.

Egg and sperm are released and fertilization takes place outside of the female’s body. Eggs develop and hatch in water. Examples: fish, amphibians

◦ 2. Internal fertilization-male and female must mate. Sperm are deposited directly inside the female’s body. Examples: reptiles, birds, mammals A. Amniotic egg-has a shell and membranes to

protect the embryo and keep it from drying out. Does not need to be laid in water. Have a yolk sac to supply food for the embryo.

A. Agnatha- Jawless Fishes - no true jaws, scales, or paired fins. Examples: lamprey eel, hagfish

II. Classes of Vertebrates

B. Chondrichthyes- have skeleton of cartilage; have gills and paired fins. Examples: sharks, rays

C. Osteichthyes- have skeleton of bone; have jaws and paired fins. Examples: perch, tuna, trout

D. Amphibia-have smooth, moist skin and no scales. Go through process of metamorphosis changing from larva stage (tadpole) living in water to adult stage living on land. During metamorphosis, lungs replace gills, limbs develop, and the tail disappears. Breath with gills at some point. Examples: frogs, toads, salamanders

E. Reptilia-have body covered with scales and toes with claws. Breathe using lungs at all stages. Examples: turtles, snakes, lizards

F. Aves-have body covered with feathers and forelimbs modified into wings. Skeleton of thin, hollow bones. Examples: pigeon, hawk, duck

E. Mammals-have body with hair on at least some part. Feed young milk secreted by mammary glands. Breathe with lungs.

A. Monotremes-mammals that reproduce by laying eggs. Only 2 living species are the platypus and spiny anteater.

Divided into 3 groups based on their pattern of development:

B. Marsupials-are born early and undeveloped. Crawl into mother’s pouch until development is complete. Includes kangaroo and opossum.

C. Placental-young develop inside the female’s uterus until development is complete; give birth to live young. Includes dolphins and humans.