Ch. 14.1: Darwin developed a Theory of EvolutionObjectives1. 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 IdeasBefore 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 EvolutionInheritance 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 DarwinProposed 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 = mechanismWell suited individ. SURVIVE & REPRO. More offspring (pass genes on)

Darwin’s ObservationsVoyage 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?