Slides in this set
· Different varieties of a gene for a particular
characteristic are called alleles.
· In sexually reproducing animals, alleles are
shuffled each time a new organism is
· It is possible for an entirely new combination
of alleles to be produced. This is done by
accident when DNA is being replicated. This is
called mutation.…read more
· E.g. Differences in skin tone, different sizes due
· Differences like these arise during the
· They cannot be passed onto the offspring
because they are not caused by DNA.
· ENVIROMENTAL VARIATION CANNOT BE
Discontinuous and continuous
· Discontinuous variation is when there are certain
groups that the variation can belong too. There is
no in-betweens... E.g. Blood group.
· this is almost always caused by genes.
· Usually only one or two genes are involved, each of
them having only a few alleles.
· Continuous variation is when a variation doesn't
fall so easily into a category. E.g. Leaf length!
· It may be caused by the environment or your genes
(or both)…read more
Charles Darwin and the theory of
· In 1856 a theory was put forward by Charles
· His book was called The Origin of Species.
· Proposed a mechanism called natural