How much evidence is
required to support a theory?
What sort of counter evidence
is required to refute it?
Adaptations are characteristics
that make an individual suited to
its environment and way of life
Individuals that are better adapted tend
to survive and produce more offspring
while the less well adapted tend to die or
produce fewer offspring
Species tend to produce more
offspring than the
environment can support
Individuals that reproduce pass on
characteristics to their offspring
Natural selection increases the frequency
of characteristics that make individuals
better adapted and decreases the
frequency of other characteristics leading
to changes within the species
Characteristics acquired
during the lifetime of an
individual are not heritable
Examples
Antibiotic resistance
Beaks in the finches
on Daphne Major
Variation
Natural selection can only occur
if there is variation among
members of the same species