Variation Flashcards
1
Q
What is interspecific Variation
A
The variation between species
2
Q
What is a intraspecific variation?
A
The variation within a species group
3
Q
What are environmental Causes?
A
- Interaction of environmental and genetic factors
e.g. chlorosis (yellow leaves)
etiolation (long thin growth)
4
Q
What are genetic causes?
A
- Gene Mutations (different alleles)
- Chromosome mutations
- Crossing over in meiosis
- Independent Assortment in chromatids and chromosomes in metaphase I and II
- Interbreeding
5
Q
Examples of causes in genetics
A
- Mutations, a change in a base sequence can lead to changes in the p
6
Q
What is discontinuous variation
A
- A characteristic that only result in a few discrete categories e.g. blood type, flowering vs non flowering
7
Q
What is continuous variation
A
Characteristics that can take any value within a range between two extremes e.g. height, body mass, leaf length
8
Q
Describe the likely genetic explanations for discontinuous variation
A
- Often due to monogenic inheritance
- Single gene locus with multiple alleles
- Patterns of dominance, recessiveness, codominance
or multiple genes acting epistatically
9
Q
Describe the likely genetic explanations for continuous variation
A
- Polygenic inheritance
- Multiple genes influencing a particular characteristic
- Multiple genes with multiple alleles
- Tend to show normal distribution
10
Q
Key features of a normal distribution curve?
A
- Mean, median and mode are the same
- Bell shape is symmetrical around the mean
- 50% of values are less and 50% are more than the mean
- Extremes are few
