Too many species to know one by one: Life is so diverse that classification is needed. Most species on Earth have not even been named yet.
The points to remember
- There is an immense diversity of species: about 8.7 million, but only about 2.1 million are named.
- So we need classification to sort them.
- Hard to count because there are too few taxonomists...
- ...and too little money to pay experts.
- Remote areas, such as mountains and deep forest, are not fully explored.
- Some species are hard to find, and some are hard to tell apart from close relatives.
Reasons that do not count: 'It has high biodiversity', 'animals migrate' or 'they live in protected areas' do not explain why a count is hard. Give a real barrier: too few taxonomists, no money, remote places, species hard to find or tell apart.
Real example: in the Amazon rainforest in Brazil, scientists still describe hundreds of new plants and animals every year, many from areas only reached by boat.
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Classification puts organisms that share features into the same group.
Why classify: identify and predict
- Organisms are grouped by shared features.
- Efficient identification: a new find is quickly narrowed down to its group.
- Prediction: members of a group share traits, so we can predict an organism's features.
- Species in the same genus are closely related and have similar traits.
- Genera are grouped into bigger groups, such as families, in the same way.
Remember it as: Group it, then you can find it and predict it.
Identification
- Narrow a new find down to its group.
- Then check a few species, not millions.
Prediction
- Members of a group share traits.
- So guess its features before studying it.
Real example: lions, tigers and jaguars are all in the genus Panthera, and all three can roar. The domestic cat, in the genus Felis, purrs but cannot roar.
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Scientists give each species a two-part name, called a binomial name.
The points to remember
- Every species has a two-part scientific name.
- First name: the genus, with a capital letter.
- Second name: the species, all in lower case.
- Both names in italics, or underlined when handwritten.
- One name, used by scientists in every language.
Write it right: Panthera leo: capital P, small l, in italics. By hand: underline both words.
Real example: the lion is Panthera leo in every country, so a scientist in Kenya and one in Japan know they mean the same animal.
How this comes up: Paper 1 and Paper 2 short parts: why species are hard to count [1-2], or reading and writing binomial names.
The Amazon rainforest in Brazil is one of the most species-rich places on Earth, yet no one knows how many species live there.
Outline two reasons why it is difficult to determine the exact number of species in the Amazon rainforest.
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