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1844
Evidence that organisms evolved
How they involved
Worried about publishing
• Prevailing beliefs
• Religion
1859 published his earth-shattering work:
On the Origin of Species by Means of Natural Selection or the Preservation of
Favoured Races in the Struggle for Life
Who was Charles Darwin?
NATURAL SELECTION
“the way in which nature favours the
reproductive success of some individuals
within a population over others”
Observations
Inferences
Theory of Natural
Selection
In each generation,
populations produce
more offspring than
there are adults
Populations do not
continue to grow in
size
Individuals within a
population compete
for resources
Food and many other
resources are limited
Individuals within all
populations vary
Many variations are
heritable
Some individuals will
inherit characteristics
that give them a
better chance of
surviving and
reproducing
Over time the
population changes
as advantageous
inheritable
characteristics
become more
common
NATURAL SELECTION
“the way in which nature favours the
reproductive success of some individuals
within a population over others”
Natural Selection
VS
Survival of the Fittest
How does evolution work?
Darwin knew that if he wanted to publish his work and take on the Scientific,
Religious and every day public, his theory needed to satisfy 3 criteria:
1. Explanatory
-no understanding of DNA or mutations
-used breeding to demonstrate his theory
 Look at what can happen in a
century –What about a million
years?
2. Predictive Powers
-different environmental conditions will lead to certain traits favoured
-resistance and location of fossils
3. Testable
-possibility of being proven wrong (Gravity  apples falling up)
-Table 1 page 307
Darwin could account for the how but not why the variation occurred
MODERN EVOLUTIONARY SYNTHESIS
“evolution is the change in the gene pool
of species over time”
Natural selection favours certain allele combinations
New combinations = mutations
neutral, harmful or beneficial
• Gene duplication
Average 20 mutations/individual
(most neutral)
Population = 7 bill
More than 100
billion
mutations!
Similar genes between species
 evolve and/or mutate over time
 relatedness
Genes that no longer code for a functioning protein
 vestigial