What Are Habitats?
A habitat is the immediate environment in which a living organism (an animal or plant), exists. A habitat can exist in any size and can even be as small as a rock pool or a log that is decaying on the forest floor. The word habitat however, generally refers to the grouping of animals and plants, together with their surroundings. Habitats contain both living organisms and non-living objects and can contain anywhere from just a few species to thousands of them, all coexisting in a very small space.
Factors That Shape Habitats
Geology has the most fundamental influence on the creating of habitats, along with climate. Mountain ranges, deserts and rainforests are all shaped by the changes beneath the surface of the earth and then rely on the climate to make them come alive. Habitats can vary from the enormous wet oceans, to the arid, dry deserts and are found everywhere you look on Earth. Temperature and rainfall are two of the biggest climatic factors that help to shape habitats, and changes in these factors can have devastating effects on habitats and animals all around the world (such as the ice melting in the polar regions).
In every habitat on earth constant chemical cycles are taking place, as chemicals are transferred from one organism to another. Out of the 25 elements that are critical to the making of living organisms, only four (hydrogen, oxygen, nitrogen and carbon) make up the bulk of all living things. Carbon particularly is passed between organisms as it is taken from the air by plants, which use it in photosynthesis (the process used by plants in order to create energy from the sun). The carbon is then moved directly into the ground through the plant and it's roots, or eaten by an animal which then moves it into the ground after going to the toilet. The main release of carbon into the atmosphere comes from the burning of fossil fuels.
For years now, the incredible variety of species (and the variety within species) has fascinated scientists all around the world. It has been noted that the greatest levels of species richness are in the regions surrounding the Equator, and the lowest levels of biodiversity are found at the poles. No-one is really sure as to the reason why the Earth is filled with such an incredible number of animal species, but more and more people are slowly becoming concerned about the effects that climate change, pollution and deforestation will have on habitats that are rich in species such as coral reefs and tropical rainforests.
Habitats are spread across enormous areas of the world such as the South American Amazon Rainforest which covers 5,500,000 km2, while the African Sahara Desert covers 8,600,000 km2 both of which are enormous regions of the planet. Animals however, are not spread out across the earth so evenly as many are still inhabiting the same regions where they first evolved millions of years ago. The colder parts of the world, such as the polar regions have little in the way of species variation as animals inhabiting these areas must be specially adapted to the cold. However, what the polar regions lack in biodiversity they make up for in population numbers as the Antarctic Ocean is home to millions and millions of crab-eater seals, which are the most numerous large mammals on the planet. Some animals are also distributed around the world in accordance with the plants that grow there, as certain species of animal must eat certain species of plant (like a giant panda needing to inhabit areas where bamboo grows).
Habitats are constantly changing due to bursting rivers, fires, storms and changes in climate. Animal species are often capable of adapting to their altered surroundings although some species of animal require very specific conditions in order to survive. Ice ages come and go, taking life with them and forcing animals into areas which they previously would not of inhabited. In the modern world, natural climate change is accelerated by the levels of pollution that are produced from the burning of fossil fuels by people, which is speeding up the naturally occurring climatic changes.
Levels Of Life
No matter where an animal lives in the world, it is always surrounded by other animals that live together in the same habitat, whether they are from the same species or from different ones. These interactions between animals and other species of animal, produce a range of different ecological levels. Starting with the individual (an animal that is independent in finding food), who is part of a population (animals from the same species living in the same area), which is part of a community (different species inhabiting the same area that depend on each other to survive), which belongs to a habitat or ecosystem, which makes up a small part of the biosphere (the collection of all environments on earth).