What Do We Know About Birds And Fish?

Birds vary enormously, but they all have certain characteristics which are the same. They have feathers, beaks, 4 limbs (the back two are legs, the front two are wings) and they all lay eggs.

Most birds have a similar life cycle, although the stages may last for different lengths of time.

Below is a video clip about birds and their life cycles.

Fish:

The common characteristics of fish are:

Fish have gills to breathe.

Fish live in water.

Fish are cold blooded.

They lay egg.

They have scales.

Here is a diagram of the life cycle of a salmon. Many types of fish follow a similar cycle.

Activity: Please research and list the main characteristics of all birds and fish. Can you find any birds or fish which are slightly unusual and don't have all of these characteristics? It is important to understand that when we group animals there are always some animals which do not fit into one group exactly. For example, although a duck-billed platypus is a mammal because it has fur and feeds its young with milk, it is exceptional because it lays eggs instead of giving birth to live young. Which birds and fish can you find that have unusual