Ch. 14.1: Darwin developed a
Theory of Evolution
Objectives
1. Summarize ideas from
Darwin’s time that
influenced his work.
2. Identify some key
observations from
Darwin’s voyage that
led to his theory.
3. Describe the two main
points of Darwin’s
theory.
Vocabulary
Evolution
Adaptation
Descent w/ Modification
Natural selection
What do you know about the
Theory of Evolution?
Do you agree or disagree?
•
Humans evolved from apes.
What do you know about the
Theory of Evolution?
Do you agree or disagree?
2. Individual organisms can evolve.
What do you know about the
Theory of Evolution?
Do you agree or disagree?
3. Populations will evolve adaptations that
they need to be successful.
What do you know about the
Theory of Evolution?
Do you agree or disagree?
4. Evolution can happen in one life time.
What do you know about the
Theory of Evolution?
Do you agree or disagree?
5. Evolution can only happen over millions of
years.
What do you know about the
Theory of Evolution?
Do you agree or disagree?
6. Humans have stopped evolving.
http://evolution.berkeley.edu/evolibrary/misconceptions_faq.php#a8
http://evolution.berkeley.edu/evolibrary/misconceptions_faq.php#a8
Old Ideas
Before Darwin
 Species are fixed or permanent
 Earth was less than 10,000 years old (and
unchanging)
Darwin’s Influences




Lyell: Study of fossils and rock record … Earth is
much older than 10,000 and Earth CHANGES.
Farmers: Selective breeding can change species.
Malthus: Economist (Famine & disease result when
population are bigger than resources. Selective
pressure)
Lamarck (1800): Inheritance of Aquired Characteristics
(Organisms can adapt!)
Lamarck’s Theory of Evolution
Inheritance of Acquired
Characteristics
Based on 3 Ideas
1. Desire (will) to change
2. Use and Disuse
3. Passing on acquired traits

Introduces idea that populations
CAN EVOLVE or CHANGE
(correct)

Knew NOTHING about
GENES/GENETICS.
Charles Darwin
Proposed THEORY OF EVOLUTION.
1. Descent with Modification
 Change in species over time.
 Modern organisms descend from ancient.
 Adaptations are acquired in response to changes
in habitat

Adaptation: Inherited trait that improves ability
to survive & repro.
2. NATURAL SELECTION = mechanism
Well suited individ. SURVIVE & REPRO.
More offspring (pass genes on)
Darwin’s Observations
Voyage on the BEAGLE
Galapagos:
Unique organisms - similar to, but
different from plants on nearest
mainland.
Each island had in chain had some
different species.
Mainland species had changed
after they colonized the islands and
adapted to new environments.
Wrote: On Origin of Species (w/ Wallace), 1858
Unique Species of Galapagos
Evolution by Natural Selection
1. Wild species show variations (due to genetics)
2. High birthrates & limited resources cause competition
(everyone can’t survive & thrive)
3. Individuals well-suited to enviro. SURVIVE & REPRO.
(SURVIVAL OF FITTEST)
4. Larger portion of each new generation will have favorable
variation.
5. Over long periods of time, small changes accumulate
(Adaptation occurs!)
6. Environment “chooses” favored traits (Selective Pressure)
Peppered Moths: Natural Selection
in Action
Which one is best “fit” for the environment?
What happened?
Relative frequency of
alleles for color
changed in the gene
pool for the
population.
Why?
Change in selective
pressure
http://www.aurumscience.com/biology/11_evolution/great_transformations.html
Self Quiz
1. You hear someone remark that evolution
says we come from monkeys. Educate
them with your response.
2. Discuss 1 influence (person) on the
development of Darwin’s theory. Explain
HOW this influence relates to Darwin’s
EVOLUTION.
Self Quiz
3. What did Lamarck get right? What did
he get wrong?
4. 2 Sentence Summary: What is evolution
and how does it work?