Zusammenfassung der Ressource
Evolution - B1
- Particular genes or accidental
changes in the genes of plants or
animal may give them characteristics
that enable them to survive better.
- over time this may result
in entirely new species
- there are different
theories of evolution
- DARWIN'S THEORY
- THE MOST WIDELY ACCEPTED
- natural selection
- states that all species of living things have
evolved from simple life forms that first
developed more than 3 billion years ago
- this is a theory because of the timescales
involved it is unlikely to ever be proven
- evolution
occurs via
this process
- - individuals
within a species
may show a wide
range of
variation
because of
differences in
their genes
- - individuals with
characteristics
most suited to
the environment
are more likely to
survive and
breed
successfully
- - those genes
are responsible
for the survival
characteristics
are then passed
down to the next
generation
- many people refused to
accept his theory because:
- - it was a conflict with religious
views that God had created the
universe and all creatures in it
- - there was
insufficient evidence
to support the theory
- Darwin had developed his
ideas from finches on the
Galapagos islands; little
research had taken place
- - the mechanisms of inheritance
and genes were not known
- LAMARCK'S THEORY
- worked before Darwin's
- based on the idea that changes occur in an
organism during its lifetime can be inherited
- in the vast majority of cases, this
type of inheritance cannot occur
- Lamarck thought herons had evolved long legs because
they stretched their legs to stay dry, as shown
- they would then
pass on these
characteristics to
their offspring
- CLASSIFICATION
- evolution and patterns of change can be studied
efficiently only if organisms are carefully defined
and their relationships understood
- living organisms
are classified into:
- ANIMALS
- PLANTS
- MICROORGANISMS
- MUTATIONS
- = *random genetic alterations
- they can cause an extreme change in
the characteristics of an organism
- if the mutation is coupled with a change
in the environment... there can be
relatively rapid change in that species