Classification

Question 1

Order of taxonomic groups.

Answer 1

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Question 2

What happens as you move down the groups?

Answer 2

As you move down towards species there are fewer organisms within each group and they share more similarities.

Question 3

Organisms can be classified in two ways:

Answer 3

• An artificial system is based on one or two characteristics that make identification easier, for example birds that always lived by the sea are called seabirds.
• 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.

Question 4

What is a species?

Answer 4

A species is a group of organisms that can interbreed to produce fertile offspring

Question 5

All organisms are named by the binomial system. The system works like this:

Answer 5

• There are two parts to the name, the first is the genus and second the species.
• The genus parts starts with a capital letter the; species part starts with a lower case letter.

Question 6

Problems with classifying.

Answer 6

• 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. 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 a reptile.

Question 7

Some organisms present specific problems:

Answer 7

• Bacteria do not interbreed, and they produce asexully so they cannot be classified into different species using the ‘fertile offspring’ idea.
• Mules are hybrids, produced when members of two species (a donkey and a horse) interbreed. Hybrids infertile, so mules cannot be classified as a species.

Question 8

Classification and evolution.

Answer 8

• Organisms that are grouped together are usually closely related and share a recent common ancestor. However, they may have different features if they live in different habitats.

Question 9

When classifying organisms, it is important to bear in mind that similarities and differences between organisms may have different explanations:

Answer 9

• Dolphins have similarities to fish because they live in the same habitat (ecologically related). However, they are classified differently - dolphins are mammals
• Dolphins and bats have evolved to live in different habitats, but both are mammals - they are related through evolution