Variation Flashcards
What is variation?
the differences in characteristics between organisms
What is inter-specific variation?
differences between member of the different species
opposite is intra-specific (between members of the same species)
What causes variation?
differences in genetic material from its parents (genetic variation)
the environment in which the organism lives (environmental variation)
What are alleles?
alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
different alleles cause different effects
individuals in a species population may inherit different alleles of a gene
What are mutations?
changes to the DNA sequence and therefore to genes can lead to changes in the proteins that are coded for
protein changes can affect physical and metabolic characteristics
if the mutation occurs in the gametes it may be passed on to the organism’s offspring
How does meiosis lead to variation?
the genetic material inherited from the two parents is ‘mixed up’ by independent assortment and crossing over
this leads to the gametes of an individual showing variation
How does sexual production lead to variation?
offspring from two individuals inherits a mixture of alleles from each of the parents
What causes siblings to differ?
many different gametes are produced from the parental genome
it is a result of chance as to which two combine
individuals produced therefore also differ from their siblings
Why are plants more greatly affected by their environment than animals?
their lack of mobility
e.g. two bushes in one garden
one gets more light
that grows more
How is height both genetic and environmental?
determined by inherited genes as well as diet
if your diet is poor you may suffer from a disease which prevents growth
How is skin colour both environmental and genetic?
skin colour is predetermined by genetics although exposure to the sun causes more melanin to be produced to protect skin from UV rays, therefore the skin becomes darker
