What do we mean by the word organisms? This word is the biological definition for all living things. And there are literally thousands of living things throughout the Earth, and possibly beyond, somewhere in the vast expanses of the universe.
Even on our own planet, the variation of life is incredibly diverse, from plant life and animals, through fungi, to the incredibly small organisms like viruses, bacteria, and protoctista. All of these living things, organisms, are incredibly important, and their chain interactions with each other, shape and effect the world in which we live.
This is why biologists study all kinds of organisms, not just the exotic, like the lions on the Serengeti or the gorillas in Uganda. But also more common organisms like insects, that would be regarded as pests by farmers, aphids for example, that attack crops, or indeed insects that would be regarded as beneficial by gardeners, ladybirds, which feed on aphids. The study of all these living things is called biology, and it is possible for anyone to make a study of organisms. Wherever you live, there will be some kind of organism close by, and by making a study of them, you will gain an understanding of how they live and interact with the world around them.
The diversity of habitats, the places where organisms live, is also varied, and organisms are found throughout the world. From temperate climates near to the equator, to the extreme colds of the Arctic and Antarctic, and to the extreme heat of the desert. Living organisms are found on land, in the seas and under the soil beneath our feet.
Plants for example are found in many varied habitats. A tree may live in a wood or a forest, and interacts with all the other living organisms within this habitat. The white water lily lives on the surfaces of ponds, and will interact with the organisms that live within this habitat, while a cactus may inhabit a hot, dry, arid desert and interact with the other organisms within this habitat.
The conditions within the habitat, for example, the hot and humid conditions that exist within a jungle, make up the environment, in which jungle organisms live. Polar Bears live in habitats with cold and icy environments. Whereas fish that inhabit the sea live in a salt water environment, some in calm protected waters, some in open water that is subject to radical changes, and some fish even live at the extreme depths of the oceans, and are subjected to extreme environmental conditions of cold, darkness and extreme pressures.
To survive, organisms need to be well adapted to the environment and habitats in which they live. You will have noticed that marine animals have similar adaptations that suit their habitat and environment. Fish tend to have flat scaly bodies, that are streamlined, and are able to move through the water with ease. Their tales and their fins are used for propulsion, balance and steering.