EvolutionEvolution

Chapter 15 of Biology TextChapter 15 of Biology Text

Chapter 4 of Environmental Chapter 4 of Environmental Science TextScience Text

Student Performance StandardsStudent Performance Standards SB5. Students will evaluate the role SB5. Students will evaluate the role

of natural selection in the of natural selection in the development of the theory of development of the theory of evolution.evolution.• a. Trace the history of the theory.a. Trace the history of the theory.• b. Explain the history of life in terms of b. Explain the history of life in terms of

biodiversity, ancestry, and the rates of biodiversity, ancestry, and the rates of evolution.evolution.

• c. Explain how fossils and biochemical c. Explain how fossils and biochemical evidence support the theory.evidence support the theory.

Lesson Essential QuestionLesson Essential Question

How do organisms adapt to their How do organisms adapt to their environment?environment?

Write down the characteristics Write down the characteristics you think help the chameleon you think help the chameleon

when it hunts.when it hunts.

Charles Darwin Charles Darwin (1809-1882)(1809-1882)

English NaturalistEnglish Naturalist Sailed on the HMS Sailed on the HMS Beagle Beagle fromfrom

1831 - 18361831 - 1836 His job was to collect biological and His job was to collect biological and

geological specimens during the geological specimens during the ship’s travels to S. America.ship’s travels to S. America.• Collected rocks, fossils, plants, and Collected rocks, fossils, plants, and

animalsanimals

Galapagos IslandsGalapagos Islands::• A series of islands off the coast of S. AmericaA series of islands off the coast of S. America• Darwin reached the islands in 1835 Darwin reached the islands in 1835 • Each island had it’s own slightly different variety of Each island had it’s own slightly different variety of

plants and animals.plants and animals.• Darwin collected mockingbirds and finchesDarwin collected mockingbirds and finches• ““Darwin’s Finches”Darwin’s Finches”• Darwin began to suspect populations from the Darwin began to suspect populations from the

mainland changed after reaching the Galapagos.mainland changed after reaching the Galapagos.• Hypothesized that new species could appear Hypothesized that new species could appear

gradually through small changes in ancestral gradually through small changes in ancestral species.species.

Galapagos Islands – a series of volcanic islands off the coast of Ecuador

Natural SelectionNatural Selection

Darwin proposed that the Darwin proposed that the environment exerts a strong environment exerts a strong influence over which individuals influence over which individuals survive to produce offspring.survive to produce offspring.

Darwin used the term Darwin used the term natural natural selectionselection to describe the survival to describe the survival and reproduction of organisms with and reproduction of organisms with particular traits.particular traits.

Add These Vocab Words To Add These Vocab Words To Your Study GuideYour Study Guide

What are What are genesgenes?? What are What are traitstraits?? What does What does heredityheredity mean? mean? What are What are heritable traitsheritable traits??

What is different about these What is different about these finches? Why?finches? Why?

Principles for Natural SelectionPrinciples for Natural Selection

1. Differences within a population are 1. Differences within a population are visible and vary in each generation.visible and vary in each generation.

2. Variations can be inherited.2. Variations can be inherited.

3. More individuals are born than live to 3. More individuals are born than live to grow up and reproduce.grow up and reproduce.

4. Individuals with some genes are more 4. Individuals with some genes are more likely to survive and reproduce than likely to survive and reproduce than individuals with other genes.individuals with other genes.

Darwin’s ConclusionDarwin’s Conclusion

Based on the 4 principles listed on Based on the 4 principles listed on the previous slide, Darwin concluded the previous slide, Darwin concluded that individuals with genetic traits that individuals with genetic traits that make them more likely to grow that make them more likely to grow up and reproduce in the existing up and reproduce in the existing environment will become more environment will become more common in the population from one common in the population from one generation to the next.generation to the next.

What is Evolution?What is Evolution?

- Darwin proposed that over many - Darwin proposed that over many

generations, natural selection causes the generations, natural selection causes the characteristics of populations to change. characteristics of populations to change. A change in characteristics from one A change in characteristics from one generation to the next is generation to the next is evolutionevolution. .

- Evolution works on populations not - Evolution works on populations not individuals.individuals.

- Evolution is CHANGE OVER TIME.- Evolution is CHANGE OVER TIME.

Support for EvolutionSupport for Evolution1. Fossil Record:

GlyptodontsGlyptodonts

ArmadillosArmadillos

Ratite BirdsRatite Birds

The Origin of SpeciesThe Origin of Species 1859 – Darwin published 1859 – Darwin published On the Origin of On the Origin of

Species by Means of Natural SelectionSpecies by Means of Natural Selection Main PointsMain Points::

• The diverse forms of life have arisen by The diverse forms of life have arisen by descent with modification from ancestral descent with modification from ancestral species.species.

• The mechanism of modification has been The mechanism of modification has been natural selection working over enormous tracts natural selection working over enormous tracts of time.of time.

Darwin used the termDarwin used the term evolution evolution only on only on the last page. the last page.

AdaptationsAdaptations

See Figure 8 on page 105 in ES Book.See Figure 8 on page 105 in ES Book. The deer’s thick fur is an The deer’s thick fur is an adaptationadaptation

– an inherited trait that increases an – an inherited trait that increases an organism’s chance of survival and organism’s chance of survival and reproduction in a certain reproduction in a certain environment.environment.

CoevolutionCoevolution

Coevolution is the process of two Coevolution is the process of two species evolving in response to long-species evolving in response to long-term interactions with each other.term interactions with each other.

Artificial Selection vs. Artificial Selection vs. Natural SelectionNatural Selection

Artificial SelectionArtificial Selection – Selective breeding – Selective breeding (dogs, plants that grow fruit)(dogs, plants that grow fruit)

Darwin inferred that the same process Darwin inferred that the same process could happen in nature to create new could happen in nature to create new species.species.

Natural SelectionNatural Selection – if given enough – if given enough time, natural selection could modify a time, natural selection could modify a population enough to produce a new population enough to produce a new species.species.

+

=

Evolution of ResistanceEvolution of Resistance

Resistance is the ability of one or Resistance is the ability of one or more organisms to tolerate a more organisms to tolerate a particular chemical designed to kill it.particular chemical designed to kill it.

See Figure 11, page 107See Figure 11, page 107 HIVHIV Antibiotics prescribed to cure Antibiotics prescribed to cure

bacterial infectionsbacterial infections

PBS Video ClipsPBS Video Clips

http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html

Watch “Isn’t Evolution Just a Watch “Isn’t Evolution Just a Theory?”Theory?”

Watch “Who Was Charles Darwin?”Watch “Who Was Charles Darwin?”