Vertebrates

• Animals that have a backbone.

• Only 5% of all organisms on Earth are vertebrates!

• Unlike invertebrates which have exoskeletons, vertebrates have an endoskeleton.

Exoskeleton Vs. Endoskeleton

Exoskeleton• Invertebrate• Hard outer covering• Protects • Does not grow with animal• Must shed and form a new

one: molting• Animal is unprotected for a

time until the new exoskeleton grows

• Heavy—animals are small compared to ones with an endoskeleton

Endoskeleton– Vertebrate– Internal support system– Protects and allows

movement– Specialized to protect the

internal organs– Grows with the animal– Not as heavy as an

exoskeleton, allows for larger animals

Exceptions!!

• Turtles have an endoskeleton and an exoskeleton.

• Jelly Fish don’t have either one, they can change shape at will.

And the Vertebrates Are….• Fish

• Amphibians

• Reptiles

• Birds

• Mammals

All of these species has a backbone but they all have different adaptations that fit their environment.

Fish• Most vertebrates are fish• Most diverse group• Adapted for life under the water• Gills remove oxygen from water and exchange it

for carbon dioxide in the fish’s blood• Swim bladder allows the fish to adjust how high

or low it floats• Lateral line is an organ in the sensory system

that allow fish to sense objects and organisms that are nearby.

• Sexual reproduction, lay eggs

Fish: 3 Groups

• Jawless: lampreys and hagfish, most similar to the first fish that lived on Earth

• Jawless fish do not have stomachs and cannot chew although they do have teeth

• Cartilaginous: Sharks, rays and skates, skeletons are made of cartilage.

• Bony: 96% of fish are in this category• Most have scales, jaws, teeth and several

pairs of fins

Amphibians

• First group of animals to live on land• Two pairs of leg• Lay eggs in water• Obtain oxygen through their smooth, moist

skin and many also have lungs• Sensory organs are adapted for sensing

on land• Sexual reproduction, lay eggs that do not

have hard shells

Life Cycle of Amphibians

• Eggs hatch in water

• The larva are called tadpoles

• Tadpoles have gills, eat algae and move by pushing with their tails

• As the tadpole grows it develops lungs, legs and its tail shrinks

• The gills stop functioning and it is ready to live on the land

Reptiles

• Evolved after amphibians• Survive in hotter and dryer environments• Two pairs of legs• Tough, dry skin covered by scales• Respiratory organs called lungs• Sensory organs are adapted for sensing on land• Sexual reproduction, lay eggs with hard shell on

land

Ectotherms

• Both Reptiles and Amphibians are Ectotherms: their body temperature changes with the environment.

• Adaptations for staying at the correct body temperature include: living near water, being able to slow their body processes during winter, standing on two feet to reduce the surface area in contact with hot sand.

Birds

• Have feathers and a beak• Four limbs: a pair of scaly legs and a pair of wings• Sexually reproduce, eggs have hard shells• Endotherms: maintain a constant body temperature• Generates heat by consuming food• This adaptation allows for diverse range of habitat• Birds can shiver to stay warm• Fluff their feathers to cool off• Seek shelter from the hottest part of the day

Adaptations for Flight

• Endoskeleton: some of the bones are fused without joints. This makes the bird lighter but not as flexible.

• Wings and Feathers• Respiratory system: air sacs and lungs move air

constantly through the bird’s body.• Hollow bones• No heavy jaw bone or teeth, they grind their food

in an organ called the gizzard.• Highly developed sense of sight and hearing

Mammals

• Hair during some part of their lives• Specialized teeth for consuming particular types

of food• Hair and body fat are adaptations for controlling

body temperature• Produce milk to feed their young• Endotherms• Sexual reproduction with the baby developing

inside the mother in almost all species

Speaking of Babies

• Fish lay eggs and leave• Amphibians also lay eggs and have nothing

further to do with their offspring• Reptiles leave the eggs once they are laid

usually. Alligators and Crocodiles will protect their nests until the eggs hatch.

• Birds incubate their eggs and care for the young• Mammals care for their young, sometimes as

long as 18 years or more!!

Questions

1. Describe how you would determine if an animal was a salamander or a lizard.

2. Imagine that you live in Mexico and you have a pen pal who lives in Iceland. Both of you want to know about animals in the other person’s country. Which of you will be more likely to have seen wild reptiles? Why?