Species

Scientists group living organisms into different kinds. Each kind of organism is called a species.

Species and reproduction

All the organisms in a species share the same characteristics but they are not all identical to each other. For example, some Indian elephants have straighter tusks than others. They have pink markings on their skin in different places. There is variation between the individual Indian elephants.

Variation between individuals can sometimes make it difficult to decide whether two organisms belong to the same species. To be sure, scientists try to find out if they can reproduce with one another.

Indian elephants reproduce only with other Indian elephants. They do not reproduce with African elephants. Each species reproduces only with other members of its own species. When they have offspring (children), the offspring belong to the same species as their parents.

The offspring are fertile. This means they can also produce offspring.

Organisms that belong to different species cannot usually reproduce with one another.

Very rarely, two organisms from different species do reproduce together. This sometimes happens in a zoo. It can happen if two animals from different species are put into the same enclosure.

For example, a male lion and female tiger in a zoo sometimes reproduce together. They will only do this if they do not have a member of their own species to reproduce with.

The young animals that are produced are called ligers. Ligers are healthy animals. But ligers cannot reproduce. They cannot have offspring. They are infertile.

So, we can describe a species as a group of organisms that can reproduce together to produce fertile offspring.