4.3.3(Evidence used in classification)

State how development in technology allows us to classify organisms more accurately

• Development in technology means that species are now classified by their DNA and proteins

Describe how biological molecules are used to classify organisms

• Amino acid sequencing was used

• This helps to find similarities and differences in amino acid sequence of proteins which are used to elucidate relationships between organisms

• Related organisms have similar DNA sequences and so similar amino acid sequences in their proteins

Describe how DNA is used to classify organisms

• DNA consists of bases

• Scientists would look at the order of the bases in each organism

• Closely related species will have a higher % of similarity in their DNA

• If there are many differences, the species have evolved separately for a long time, and so they can be considered less closely related

Explain why using molecular evidence may be a more accurate method for classifying plants than morphological evidence

• Plants with the same niche requirements often have adapted in a similar manner morphologically

• Molecular evidence avoids the confusion potentially posed by adaptation

Define the term convergent evolution

• When 2 unrelated species adapt in a similar way and therefore look similar