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Investigating Diversity

The theory of evolution is a model used by some scientists.Comparing genetic diversity between species helps scientists determine theoretical evolutionary relationships. It also helps in the classification of organisms.In order to determine the relationships between organisms the scientists can:
  • compare observable characteristics
  • compare DNA base sequences
  • compare mRNA
  • compare amino-acid sequences
Each observable characteristic determined by genes and the environment and the variety of characteristics depends on number and variety of alleles of the genes.The limitation of using observable characteristic is classification is that a large number of characteristics are coded by more than one gene (polygenic), so variation is continuous and not discrete and it is difficult to distinguish one characteristic from another. The characteristics may also be modified by the environment. Examples are height and weight in humans which are influenced by diet.

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Specification: AQA Biology (7401), AS-level, 3.4.7 Investigating diversity. Topic: Biodiversity.

Key terms in this lesson

gene
A length of DNA that codes for a polypeptide or a functional RNA molecule, at a specific locus on a chromosome.
allele
One of the different versions of a gene, arising by mutation, that occupy the same locus on homologous chromosomes.
species
A group of organisms with similar characteristics that can interbreed to produce fertile offspring.
classification
The organisation of living organisms into groups based on their similarities and differences.
genetic diversity
The variety of alleles present within the gene pool of a population or species.

More in Biodiversity

All 33 lessons in Biodiversity · All AQA AS-level Biology topics