Transcript Darwin`s Theories

STRUGGLE FOR EXISTENCE
• Darwin’s central theme
• Based on Malthus’s work on
population growth
FITNESS
• A Key factor in the struggle for
existence
• The result of adaptations
• Central to natural selection
NATURAL SELECTION
• Only certain individuals produce
new individuals
• Over time, it will result in changes
in the inherited characteristics of
a population. These changes
increase a species’ fitness in its
environment.
DESCENT WITH MODIFICATION
• Each living species has
descended, with changes, from
other species over time.