Types of Variation Flashcards
How can alleles cause genetic variation
Which allele is inherited from parents will determine the variation. E.g. blood group A, B and O)
How can mutations cause genetic variation
sequential changes in DNA, leading to protein changes, can affect physical and metabolic processes. If somatic then affects just the individual, if its in the gametes may affect the offspring.
How can meiosis cause genetic variation
Gametes produced with ½ genetic material of parent. Variation furthered by independent assortment and crossing over.
How can sexual reproduction cause genetic variation
offspring inherits alleles from 2 parents.
How can chance cause genetic variation
during sex it is random which gametes will join to form new offspring.
List genetic causes of variation
Alleles, Mutation, Meiosis, sexual reproduction and chance
(3, 4 and 5 are all sexual. Therefore there is greater variation in sexually reproduced organisms than in asexual reproduction).
What is intraspecific variation
The differences between individuals of the same species
What does variation within a species rely upon
Mutations within species
what is interspecific variation
The differences between different species
What are the causes of variation
Genetic material of the organism and environmental variation
What is environmental variation
Variation due to the organisms surrounding, usually affecting plants more as they are less mobile.
What part of the environment affects plants
sunlight and soil content. E.g. hydrangeas.
Give an example of environmental variation in humans
Scars
What is the majority of variation caused by
A combination of both Environmental and Genetic variation
Give an example of how environmental and genetic variation work together
If you have genes for tallness but insufficient food you will not be as tall as someone in an environment that afforded enough food.
What is variation
The existence of variety and differences within and between species.
Why is measuring variation difficult for biologists
because they are measuring some aspect of a living organism and all living organisms are different.
How can measuring variation be overcome
With Sampling
What does sampling involve
Taking a selection of individuals from the target population who will represent the population as a whole
What are the problems with sampling
Sampling bias and chance (Random sampling and a large sample can help combat this)
What is meant by sampling bias
The selection process may be biased. The investigators may be making unrepresentative choices, either deliberately or unwittingly.
What is meant by chance
Even if sampling bias is avoided, the individuals chosen, by pure chance, may not be representative.
Give examples of continuous variation
height, weight, length, size (Normally presented in a bell curve)
Give examples of discontinuous variation
sex, blood groups, colour (Usually presented as a bar graph)
