In a nutshell

Extinction of many species is a growing problem we are facing as the impact of human activity on the environment increases. It is important to know what causes extinction and what we can do to preserve diversity.

Definition

Extinction is when a species completely dies out and there are no more organisms of the species alive anywhere.

Causes of extinction

In order for species to survive, it needs to be well adapted to its environment, be able to compete with other organisms and be able to reproduce. When an environment changes, a species may be less well adapted to it and it will not be able to compete successfully for resources. Therefore, the species cannot survive and reproduce.

When this happens, the whole species is at risk of becoming endangered and extinct.

Conservation techniques are used to prevent a species from becoming extinct. However, once a species has become extinct, it is gone forever.

Causes of extinction

Environmental changes	Human Induced changes
Changes in temperature.	Illegal hunting
Changes in food availability.	Building homes and infrastructure
Competition from a new species.	Global warming
Hunting by a new predator.	Pollution
A disease that kills the species.	Pollution

Examples

Dinosaurs became extinct following the meteor impact. This may be due to changes in the environment that the impact caused.
Elephants are hunted for their tusks, which contain ivory. Their habitats are also quite large and are often destroyed to make space for new human settlements. This has resulted in elephants becoming endangered and at risk of extinction.
Several years ago humans destroyed the habitat of dodos by making houses. They also brought animals that increased competition for the resources that dodos also use and introduced new predators. This resulted in the dodo becoming extinct.

Definition

Biodiversity is the variety of species found in an ecosystem. It is very important as it provides a large variety of resources such as food sources and types of shelter. This allows many populations of species to co-exist in the same area.

Note: Tropical habitats such as rainforests have high biodiversity, whereas harsh habitats such as deserts have low biodiversity.

Maintaining biodiversity

There are many reasons we should do our best to maintain biodiversity.

By preserving biodiversity, we preserve the stability of ecosystems so that they stay healthy.
We can also use different plant species as medicines.
Variation protects our future food supply.
The economy can benefit from ecotourism if there are lots of different animals and plants to see. This can provide income to a country as well as jobs for the local people.
Future generations can enjoy the variety in wildlife.

Conservation

Biodiversity can be maintained and species can be protected through a number of different measures:

Habitats can be legally protected.
Artificial ecosystems, like nature reserves, can be managed by humans.
Captive breeding programmes can be run where animals are bred in a safe environment away from threats like predators so that their population can increase.
Education programmes can be run to make people aware of the threats to endangered species and what they can do to increase biodiversity.

Bringing back extinct species

Scientists are developing new methods to preserve or engineer genetic material in the hopes that we can use it to bring back extinct species in the future.

Gene banks

Seed banks are a type of gene bank for plants where seeds are stored in a way that they do not grow into plants immediately. By preserving seeds, we can replant them in future if the plant goes extinct.

Cryobanks are another type of gene bank where sperm and eggs are frozen to preserve their genetic material. These cells can then be fertilised in future breeding programmes if a species goes extinct.

Genetic engineering

Genetic engineering is also being used by scientists to see if they can recreate the DNA of an extinct species. However, it is difficult and yet to be carried out successfully.