Chapter 10.5 Flashcards
What is a variation?
The differences in characteristics between organisms
What does inter-specific variation?
Is the widest type of variation in between membranes of different species
What are the 2 causes of variation?
Organisms genetic variation - differences in the genetic material an organisms inherits from its parents leads to genetic variation
Environmental in which the organisms lives in - causes environmental variation
What causes genetic variation?
Genes (and alleles) an individual posses
What are the 5 causes of genetic variation within a population
Alleles (Variants) Mutations Meiosis Sexual Reproduction Chance
How does mutation cause genetic variation?
Changes in the DNA sequences and therefore to genes can lead to changes in the protein that are coded for
These proteins changes can affect the physical and metabolic characteristics. If mutation occurs in somatic (body) cells, just individual is affected.
However if mutation occurs in the gametes it may be passed on to the organism’s offspring. Both can result in variation
How does meiosis cause genetic variation?
Gametes are produced by meiosis in organisms that reproduce sexually - were each gametes receives half the the genetic content of the parent cell.
Before the nucleus divides and chromatids of a chromosome separate. The genetic material inherited from the the two parents “mixed up” by independent assortment and crossing over
{This leads to individual gametes showing variation}
How does Sexual Reproduction cause genetic variation?
When offspring produced from two individuals inherits genes (alleles) from each parent
Each individual produced therefore differs from the parents
How does Chance cause genetic variation?
Many different gametes are produced from the parental genome
During sexual reproduction it is a result of chance to combine (referred as to as random fertilisation).
When individuals produced therefore also differ from their siblings… as each contains a unique combination of genetic material
As a result, there is much greater variation in organisms that reproduce sexually than asexually
What is the “NATURE VERSUS NURTURE”?
Is the idea that many characteristics are caused by combination of both genetic and environmental causes = so it is very difficult to investigate and draw conclusions about the causes of a variation in any particular case
How does alleles cause variation?
Different genes have different characteristics. So individuals inherit different alleles causing variation
