[18.2] variation in phenotype Flashcards
1
Q
what causes variation? (3)
A
- genetics
- environment
- epigenetics
2
Q
how might genetics cause variation? (3)
A
- mutations
- meiosis
- random fertilisation of gametes
3
Q
how might environment cause variation? (2)
A
- food availability
- prevailing wind can affect direction of tree growth
4
Q
what are the 2 types of variation?
A
- continuous variation
- discontinuous variation
5
Q
describe continuous variation
A
two extremes and a full range of intermediates
eg. height, weight, length of leaves
6
Q
what causes continuous variation?
A
the interplay of genetics and environment
7
Q
describe discontinuous variation
A
2 or more discrete categories with no intermediate values
eg. eye colour, flower colour, blood group
8
Q
what causes discontinuous variation?
A
alleles of a single gene or a small number of genes
