- most have 4 limbs (legs) with usually five clawed toes
- have backbones
- breathe with lungs
FISH
- breathe with gills
- have backbones
- most lay eggs
- have scales
- are cold-blooded
- have fins
AMPHIBIANS
- lay eggs
- are cold-blooded
- have backbones
- go through metamorphosis -
first they breathe with gills
then they breathe with lungs
- have smooth, moist skin
BIRDS
- lay eggs
- have feathers
- have backbones
- are warm-blooded
- breathe with lungs
- have two wings,
two feet and one beak
MAMMALS
- have backbones
- give live birth
- have fur or hair
- nurse their young
- are warm-blooded
- breathe with lungs
B)INVERTEBRATES
Over 90% of all animals fall into the category of invertebrates or animals without backbones. Many, however, have exoskeletons which means that they wear their skeletons on the outside of their bodies such as crustaceans (crayfish), spiders and insects. Invertebrates are cold-blooded which means their body temperature depends on the temperature of their surroundings (environment). They must change their body temperature by moving into the sun or sitting in the shade. Just a quick reminder that Worms, Molluscs, Sponges and Arthropods are four divisions under the category of invertebrates. Now it's time to take a look at the characteristics of these 4 groups.
Characteristics Of The Invertebrates
WORMS
- over 7000 types
- have several hearts
- can be both male and female
called hermaphroditic
- lays eggs
- no lungs breathe through
tiny holes in its skin
- has over 100 body segments
- long, soft body and no legs
- moist with bristles on the body
- goes through a series of
changes in their life cycles
MOLLUSCS
- lay eggs
- are soft-bodied
- sometimes protected by a shell
- bodies are unsegmented
SPONGES
- have no cells, tissues or organs
- have no mouth
- can be both male and female called hermaphroditic
- has thousands of pores which continually let water flow through (food, oxygen, waste)
- lays eggs
ARTHROPODS
- has a jointed body
- has jointed legs
- most have external skeletons - exoskeleton cannot grow - shed its skeleton (molting)
- has no arteries / veins to carry blood - blood pumped through open spaces to tissues
- has compound eyes
- go through a series of changes in their life cycles ( larvae - pupa )
