Speciation in the genus Allium by polyploidy
What is Speciation?
The formation of new species due to evolution.
What are the two ways in which speciation can occur?
Gradualism - small, continuous and slow changes
Punctuated gradualism - Abrupt changes followed by long periods of no change.
What is a Polyploidy?
Haploid = One set of chromosomes = monoploidy
Diploid = 2 sets of chromosomes
3n = triploid 4n = tetraploid 5n = pentaploid
A cell which has three or more sets of chromosomes is called a polyploidy.
This is more common in plants than animals and is caused when cells do not divide properly.
Speciation of the genus Allium by polyploidy:
Allium genus - Plants such as onions, garlic, shallots and leeks
Some have 8 chromosomes, some are tetraploid, some have 24 chromosomes and some have 32 chromosomes. This can improve the quality of the fruit as it is more likely to have advantageous genes.
Ways of Speciation
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