Question | Answer |
All organisms are classified into a number of different groups. What are these groups? | The groups are: kingdom, phylum, class, order, family, genus and species. |
What happens as you move down towards 'species'? | As move down towards 'species', there are fewer organisms within each group and they share more similarities. |
Organisms can be classified in two ways. What are these two systems called? | Organisms can be classified in two ways: - An artificial system - A natural system. |
What is the artificial system based on? | An artificial system is based on one or two characteristics that makes identification easier. |
Give an example of when an artificial system can be used. | For example, birds that always live by or on the sea can be called seabirds. |
What is the natural system based on? | A natural system is based on evolutionary relationships and is much more detailed. Animals that are more closely related are more likely to be in the same group. |
What has sequencing the bases in DNA enabled scientists to do? | Sequencing the bases in DNA has enabled scientists to know much more how closely related organisms are, and has often meant that organisms can be reclassified. |
What is a species? | A species is a group of organisms that can interbreed to produce fertile offspring. |
All organisms are named by the binomial system. How does this system work? | All organisms are named by the binomial system. The system works like this: - There are two parts to the name, the first is the genus and the second the species. - The genus part starts with a capital letter; the species part starts with a lower-case letter. |
What makes it difficult to place organisms into distinct groups? | Living things are at different stages of evolution, and new ones are being discovered all the time. This makes it difficult to place organisms into distinct groups. |
Give an example of this. | An example of this is Archaeopteryx. This creature had characteristics that would put it into two different groups: - It had feathers, like a bird. - It also had teeth and a long, bony tail, like reptile. |
Some organisms present specific problems. Why does bacteria create such problems? | Bacteria do not interbreed, they reproduce asexually, so they cannot be classified into different species using the 'fertile offspring' idea. |
How do mules also create such problems? | Mules are hybrids, produced when members of two species (a donkey and a horse) interbreed. Hybrids are infertile, so mules cannot be classifies as a species. |
Organisms that are grouped together are usually close related and share a recent common ancestor. However how can they have different features? | Organisms that are grouped together are usually closely related and share a common ancestor. However, they may have different features if they live in different habitats. |
What is it important to bear in mind when classifying organisms? | When classifying organisms, it is important to bear in mind that similarities and differences between organisms may have different explanations. |
Dolphins have similarities to fish because they live in the same habitat (ecologically related). However, they are classified differently, why is this is? | However, they are classified differently - dolphins are mammals. |
Dolphins and bats have evolved to live in different habitats, but both are mammals. How are they related? | They are related through evolution. |
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