How Animals Grow and Reproduce • Vertebrates- are animals with backbones. • Vertebrates can be grouped into 5 classes: • Mammals • Birds • Reptiles • Amphibians • Fish • Mammals are vertebrates that have hair or fur on their bodies. They drink milk from their mother’s bodies. • Reptiles are vertebrates with scaly skin. • Birds are vertebrates with feathers and wings.
Invertebrates • Invertebrates are animals without backbones. • The simplest invertebrates are corals, sponges and jellyfish. • Earthworms are invertebrates that breakdown material in soil. • The largest group of invertebrates is the arthropod group. • Arthropods have body parts in segments such as crustaceans and spiders.
Stages of Life • Life Cycles are stages of life of an organism. • Every life cycle begins with a fertilized egg. • Some organisms completely change form as they grow this is called metamorphosis. • In complete metamorphosis an insect goes through 4 stages in it’s life cycle.
Complete Metamorphosis • 1. The insect begins life as an egg. • 2. The egg hatches to produce a larva. The larva eats and quickly grows in size. • 3. A larva develops into a pupa. This is called the “resting stage” because there is no movement. • 4. The adult emerges from the pupa and can fly and reproduce.
Incomplete Metamorphosis • Incomplete metamorphosis has 3 stages: the egg, nymph and the adult. • Nymph stage is like a smaller version of the adult but a nymph can’t fly or reproduce.