Evolution
Mr. Ardito’s Living Environment Classes

Overview
• No change, no evolution
• If individuals and species stayed
exactly the same OR
• If the environment stayed exactly the
same
• THERE WOULD BE NO EVOLUTION

Sources of Change
• Overproduction
• Genetic variation
• Struggle for existence (competition)
• Differential survival and reproduction

Overproduction
• Organisms tend to produce more
offspring than are necessary
• This allows a greater likelihood of any of
the offspring to survive to adulthood
and reproduce

Genetic Variation
• No two individuals in a species are
exactly alike
• This is normal and desirable