18.2 variation in phenotype

Question 1

what 3 genetic factors create variation

Answer 1

mutations
meiosis
random fertilisation of gametes

Question 2

how do mutations create variation

Answer 2

sudden change to genes and chromosome

which may be passed on to next generation

Question 3

how does meiosis create variation

Answer 3

a special form of nuclear division

produce new combinations of alleles

Question 4

how does random fertilisation of gametes create variation

Answer 4

sexual reproduction produces new combinations of alleles

which gamete fuses with which is random, further adding to variety

Question 5

features of variation due to genetic factors

Answer 5

discontinuous
distinct group, no overlap e.g. blood types
caused by differences of a single gene
represented by pi chart or bar graph

Question 6

features of variation due to environmental factors

Answer 6

continuous.
difficult to sort into distinct groups.
most characteristics in humans. physical and metabolic.
several different genes acting in a complex way, difficult to distinguish separate phenotypes.
most fall in middle range, few extreme.
represented by a normal distribution (bell shaped) curve.