Animals live in almost every environment on Earth. The majority of animals live in water. However, many live on land.
z
Fig. 5.1.2 Animals
Animals are multicellular organisms. They can respond to changes in their environment and move about in search of food, water, shelter and mates.
All of the changes in an organism’s environment are called stimuli. Animals are consumers. This means that they must find and eat their food.
There is huge variety within the animal kingdom – some animals have wings, others have arms; some have lungs and others have gills.
Animals can be divided into two groups: zz
zz z
Fig. 5.1.3 Invertebrates
Spider Crab Invertebrates Wasp Vertebrates Bird Starfish Snail Fish Plants z
Fig. 5.1.5 Plants
Plants are multicellular. They have chlorophyll and are able to produce their own food by photosynthesis. They in turn provide food for other living things.
Frog Snake Kangaroo
Invertebrates are animals that do not have a backbone. For example, insects, snails, crabs and starfish.
Vertebrates are animals that do have a backbone. For example, humans, crocodiles, fish and birds.
z
Fig. 5.1.4 Vertebrates
Human Crocodile
84
Plants remove carbon dioxide from the air, which is important in keeping the oxygen and carbon dioxide in the Earth’s atmosphere balanced.
