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Evolution
The Puzzle of Life’s Diversity
Charles Darwin

Proposed the Theory of Evolution
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The father of evolution
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Made the greatest contributions to our
understanding of how species evolved
over time.
Fossils

Preserved remains of ancient
oragnisms.
– Why are they different then what lives
here on earth now.
Artificial Selection

The process of humans selecting the
variations that they find most
attractive or useful, and breeding or
reproducing those traits in the new
offspring.
Natural selection

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Allowing nature to take its course
naturally letting the animals mate and
the flowers pollinate without any
human interference.
AKA: Survival of the Fittest
– Weaker animals and unfavorable plant
characteristics will die off over time.
Evolution by Natural
Selection
3 Related Hypothesis

Darwin hypothesized that high birth
rates and a shortage of life’s basic
needs would force organisms into
competition for resources. He termed
this theory:
– The Struggle for Existence: Members
from each species compete regularly to
obtain food, living space, and other
necessities of life.
Evolution by Natural
Selection
3 Related Hypothesis

Darwin also hypothesized that in order
for organisms to survive they must be
well suited to their environment. He
termed this theory the:
– Survival of the Fittest: Individuals
that are better suited to their
environment survive and reproduce most
successfully.
Evolution by Natural
Selection
3 Related Hypothesis

Darwin lastly hypothesized that over
long periods of time, natural selection
produced organisms that have
different structures resulting in today’s
species looking different than their
ancestors from generations past. He
called this theory:
– Descent with Modification: Each
living species has descended, with
changes, from other species over time.
What does the word
fitness mean?



Is it your athletic ability?
Is it how nice you look in your clothes?
Fitness: The ability of an individual
to survive and reproduce in its specific
environment.
So what is an adaptation?


Um….. Is it a plug for my cell phone?
Adaptation: An inherited
characteristic that increases and
organisms chances for survival.
Evidence of Evolution

Darwin argued that living organisms
have been evolving on the earth for
millions of years. His evidence is
found in:
– Fossil Records
– Geographical Distribution of living species
– Homologous structures
– Similarities in embryonic development