3. First Vertebrates
Fishes that first appeared about 500 million years
ago
Called Agnathans- had no jaws or paired fins
Lead to the development of jawless fishes
4.
5. Characteristics of All Fishes
Gills
Chambered heart (closed system 3 main chambers)
Single loop circulatory system
Kidneys
Either Male or Female
6. Jawless Fishes
Mouth but no jaws
Cartilaginous skeletons
Eel like
Unpaired fins
Suction cup like mouth
Includes:
1. Lampreys
2.Hagfish
9. Cartilaginous Fishes
Have jaws
Have teeth (which are modified scales set in rows)
Cartilaginous skeleton (light weight but very strong;
made of calcium carbonate)
Internal fertilization
Most give live birth
Includes:
1. Sharks
2.Skates
3.Rays
13. Bony Fishes
Skeletons are made bone
Developed lateral line system: sensory systems that
extends along the each side of their bodies;
1. allows them to know where their body is in relation
to the water; depth, and place;
2.allows the to sense objects not moving in the water
Swim bladder: allows them to move deeper or
shallower by adjusting the amount of gas in the
bladder
Operculum: gill covers
22. Reptiles
Class Reptilia
Includes lizards, snakes, turtles, tortoises, crocodiles
and alligators
Found through out the world except in the coldest
regions. Why?
Have bone skeleton with the legs more directly
under their body. Allows reptiles to move on land
easier than amphibians
Ectothermic metabolism
Dry scaly skin- almost water tight
Amniotic eggs
23. Reptiles
Lungs
Ventricle of heart partly divided by septum. Oxygen
poor and oxygen rich blood mix.
Crocodiles have a completely separated heart
Internal fertilzation
Oviparous – young hatch from eggs.
Some species are ovoviviparous – female retains
eggs inside her body until shortly before hatching.
Offspring are more able to fend for themselves and
less vulnerable to predators
27. Birds
Class Aves
Forelimbs modified into wings
Body covered in feathers (modified reptilian scales,
used for flight and insulation)
Lightweight bones (thin and hollow, many are fused
to make more rigid)
Endothermic metabolism (4 chambered heart) (body
temperature range from 40-42 degrees C)
28. Birds
Super efficient respiratory system
Young are hatched from eggs
Internal fertilization
Body sizes and shapes are adapted to environment
the bird lives in, main source of food, and main
means of escaping predators
29. Mammals
Class Mammalia
Hair
Endothermic metabolism (4 chambered heart)
Mammary glands (produce milk to nurse young)
Live birth
Teeth size and shape are determined by food.
(herbivore’s teeth are flat for grinding, carnivore’s
teeth are sharp for ripping and tearing food)
30. Mammals
Very diverse group
You have the Monotreme (platypus)
Marsupials
Placental mammals (young develop within the
females uterus where the placenta allows for
diffusion of nutrients from the mothers blood to the
young)
