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How did this happen?

Wolf ----------------------> Poodle

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Types of Theories

Wolf ----------------------> Poodle

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Lamarck’s Theory of Evolution (WRONG!)Idea called Law

of Use and Disuse

If a body part were used, it got stronger

If body part NOT used, it disappeared.

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Lamarck’s Theory of Evolution

Inheritance Of Acquired Traits Traits Acquired During Ones Lifetime

Would Be Passed To Offspring

Clipped ears of dogs would be passed to offspring!

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Gradualism:

Long time Long time scale events scale events

that gradually that gradually create and create and destroy destroy species.species.

Charles DarwinCharles Darwin

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Short periods of time with “rapid” leaps in evolution. Usually after a major extinction event.Steven Gould

Punctuated Equilibriu

m:

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Parallel Evolution:

Different Animals On Different Continents But Similar Adaptations To Shared Environments

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Changes in Allele Frequency

how traits were inherited (Traits are passed through genes)

Genes Are NOT Changed By Activities In Life

Change Through Mutation Occurs Before An Organism Is Born

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EvolutionDiversity of Life

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History of Evolutionary Thought

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:

Contributor’s to Darwin’s thinking included:

• John Baptiste Lamarck – Inheritance of acquired Characteristics and Law of Use and Disuse

• Alfred Russel Wallace – organisms evolved from common ancestors

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Hutton’s Theory of Geological Change

Changes in Earth’s crust due to slow continuous processes

Ideas Known as Uniformitism and Gradualism based on fossil record

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Principles of Geology

Provides evidence to support evolution of life

Explained Geological Processes That Shaped The Earth

Helped Darwin Understand Sea Shells In The Andes Mountains At 12,000+ Feet Expanded Earth’s Age to billions of

years

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Charles Darwin the Naturalist

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Charles Darwin Born Feb. 12, 1809 Joined Crew of HMS

Beagle, 1831 Trained in Theology

and a Naturalist 5 Year Voyage around

world Avid Collector of Flora

& Fauna Astounded By Variety

of Life

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HMS Beagle’s Voyage

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Galapagos Tortoises

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Darwin’s Observations

Both Living Organisms & Fossils collected

Fossils included:TrilobitesGiant Ground Sloth of South AmericaThis species NO longer existed.This species NO longer existed.

What had happened to them?What had happened to them?

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Evidence for Evolution – The Fossil RecordEvidence for Evolution – The Fossil Record

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Evolution Principles

What Pressures Cause Evolution ?

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Definition

• Evolution is the gradual change in a population of organisms over time

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1. Overproduction:

- More offspring produced than needed.

- Only a small fraction of offspring survive and reproduce.

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2. Competition:

- food, water, space and mates are limited

- Competition within the species and with other species

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3. Variation

- There is variation within populations.

- Individuals of a population vary in their genetic traits.

- No two individuals are exactly alike.

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4. Adaptations

Because of variations some individuals are better adapted to survive in their environment

“Survival of the Fittest”

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Adaptations

Those that survive and reproduce have the fittest genetic variations.

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5. Natural Selection

Some genetic traits are selected for by environmental conditions.

Those selected for survival live and pass on their beneficial genes.

Others die and genes are lost.

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Extinctions

Some species disappear due to a catastrophic event in nature (humans, asteroid, earthquake…)

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6. Speciation• Over time favorable adaptations

gradually accumulate in a species and unfavorable ones disappear.

• Eventually the accumulated changes result in a new species.

Common Descent with Modification

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Genes create evolution!

The mutation or combination of alleles has to already be there by chance. 

Populations do not decide to adapt or mutate after an environmental change

Only beneficial mutations lead to evolution!

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What Kinds of Evidence are Used to Study Evolution?

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Selective Breeding

Artificial SelectionSelective Breeding To Enhance

Desired Traits Among Stock or Crops

Dogs, horses, fruits, corn etc..

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Artificial Selection

36Yum!

Wild Mustard was artificially selected to become broccoli!

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Natural Selection

Cannot Be Seen DirectlyIt Can Only Be Observed As

Changes In A Population Over Many Successive GenerationsRadiationFossil Record

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Fossil Record

Earth is Billions of Years Old

Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time.

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Evidence for Evolution – The Fossil RecordEvidence for Evolution – The Fossil Record

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Descent With Modification

41Similarities in DNA Similarities in DNA SequenceSequence

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Evolution Evolution of of

pesticide pesticide resistancresistanc

e in e in response response

to to selectionselection

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Homologous Body Structures

Structures That Have Different Mature Forms But Develop From The Same Embryonic Tissues

Strong Evidence That All Four-Limbed Animals With Backbones Descended, With Modification, From A Common Ancestor

Help Scientist Group Animals

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Homologous Body Structures

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Similarities In Early Development

Embryo – early stages of vertebrate development

Embryonic Structures Of Different Species Show Significant Similarities

What is similar in the next slide?

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Same stages of embryos

Which one is the Human?

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Same stages of embryos

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Human Fetus (5 weeks) with vestigal structures.

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Chicken

Turtle

Rat

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One more time for Darwin….

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Darwin's TheoryVariationIndividual Organisms In Nature Differ

From One Another. Some Of This Variation Is Inherited

OverproductionOrganisms In Nature Produce More

Offspring Than Can Survive, And Many Of These Offspring Do No Reproduce

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Darwin's TheoryCompetitionMore Organisms Are Produced Than

Can Survive, Members Of Each Species Must Compete For Limited Resources

AdaptationEach Organism Is Unique, Each Has

Different Advantages & Disadvantages In The Struggle For Existence

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Darwin's Theory

Natural SelectionIndividuals Best Suited To Their

Environment Survive & Reproduce Successfully – Passing Their Traits To Their Offspring.

SpeciationSpecies Change Over Time. Over Long

Periods, Natural Selection Causes Changes That May Eventually Lead To New Species

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Darwin's Theory

Species Alive Today Have Descended With Modifications From Species That Lived In The Past

All Organisms On Earth Are United Into A Single Tree Of Life By Common Descent