Introduction

Generally, biodiversity is described as the variety of life on Earth. To be more specific, biodiversity is thought of as the combination of genetic diversity, species diversity and ecosystem diversity. This concept is extremely important and is helping people responsible for conservation to do a much better job. It helps us to understand our interdependent and complex environment by seeing the whole picture.

The definition of a single species is a group of organisms that can interbreed to produce a new generation of offspring that can reproduce themselves. The concept is muddied by some organisms that can reproduce asexually and the constant and slow process of evolution.

Extinction of species is an ongoing process. There have been periods during the long history of Earth where extinction rates were extremely high. We are in one of those periods right now. It is not difficult to work out why the extinction rate is so high.

Activity outline

Students work in small groups and access information from the web, library and/or textbooks.

This activity has four parts:

1. Defining a species.

2. How are species named scientifically and why is it important?

3. Provide examples of plants and animals living in Australia that are indigenous, domesticated and pests.

4. Identifying some causes for a species becoming extinct.

1. Defining a species

Students are given five minutes to make a list of criteria that define a species i.e., what similarities does each of the organisms have in order to belong to a single species.

As a class list all the ideas on a board. Highlight the most important ideas. At the conclusion everyone records how the class has determined the species is defined.

Teacher tip: A clear example to demonstrate the definition of a species is that of the infertile mule. The mule is the offspring of a male donkey and a female horse and though these two animals are closely related they are of different species, as the mule offspring is infertile.

2. Species scientific naming

Student background: There are millions of species living on the planet, and some species are yet to be discovered! In order for scientists to study certain species, as well as work on their conservation, we must have a unique scientific name for each species. We call this scientific name a binomial name.
In this challenge students look at the scientific names of plants, animals, bacteria and fungus and work out what criteria scientists use for naming living things. Some questions to ask are:

How many words are used to name an organism?
What sort of language does it appear to be written in?
Is there any special way capitals are used, or the kind of type?
Can they work out which of the words is the genus?
What can they find out about the genus?

Bring the class together and see if they can piece together some of the rules for naming organisms. Do the same rules apply to all the major groups of organisms? Review that students can separate scientific names from common names.

Teacher tip: Binomial naming involves organising an organism's scientific name into a combination of two terms, these terms are the genus name and the species name. Both of these terms are italicised and the first letter of the genus name is in capitals. For example the scientific name for humans is Homo sapiens. The genus is Homo and the species is sapiens. Most names use Latin or Greek but some names are the surname of the scientist who discovered the species. Another good example for your students is the Eastern Grey Kangaroo (common name). Its scientific name is Macropus giganteus. The genus Macropus is derived from the Greek word for long foot, and the species name giganteus means big!

3. Indigenous, domestic and pests

To protect biodiversity we need to first know which species naturally belong in an area. There may be many other species that don’t naturally belong. In this activity students sort organisms living in Australia that are:

1. Indigenous - naturally evolved and occurring in Australia.

2. Domesticated - plants and animals including crops, garden plants, livestock and pets which have been brought into Australia.

3. Pests - including weeds and feral animals which have been brought into Australia.

Use the Indigenous, domestic and pests activity sheet to record the findings.

4. What causes species to become extinct?

Before groups of students start their web search ask what theories they have heard of why dinosaurs became extinct. What is meant by the word extinct? What may have been the cause for dinosaur extinction?

Students use a web search engine using two or more words to locate causes for extinction. Students are to list as many causes as they can find within a short time e.g., five minutes. It is not necessary to record any species, just causes. They should also record the two or more words that were most useful in doing their search.

After they have sourced their information the class should compile a common list. Once the list is displayed sort the causes into natural and the causes which can be blamed on human activity directly or indirectly.

Which combinations of words worked best for students to locate the information they were seeking?

What's a Species?

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