Types of selection and polyploidy Flashcards
What is the phenotypic range?
The phenotypic range is the range of how a phenotype can be expressed. Coloured eyes for example.
What are the 3 modes of selection?
Stabilising selection, disruptive selection & directional selection.
What is stabilising selection?
In stabilising selection both extremes of the phenotypic range are selected against while the middle section is selection for. Showing as a large hill.
What is disruptive selection?
The opposite of stabilising selection in that it selects for extremes rather than averages.
What is directional selection?
Directional selection is when a single phenotype is selected for.
What is the definition of polyploidy?
Polyploidy refers to the variation in the number of chromosome sets.
What is autopolyploidy?
Autopolyploidy is the scenario where the genome is multiplied with a single species. (The parent has supplied its offspring with two or more sets of chromosomes)
What is allopolyploidy?
Allopolyploidy is the hybridisation between species where the offspring has chromosomes containing more than two genomes.
What is the difference between autopolyploidy and allopolyploidy?
Autopolyploidy appears when an individual has more than two sets of chromosomes, both of which from the same parental species. Allopolyploidy, on the other hand, occurs when the individual has more than two copies but these copies, come from different species.
How does polyploidy arrise?
It arrises due to non-disjunction during cell division.
What does Instant speciation mean and how does it relate to polyploidy?
Instant speciation in polyploidy is when an individual from a certain species has duplicated or multiplied set of chromosomes and cannot reproduce with its parent population due to hybrid sterility. Therefore causing “Instant speciation”.
