1 how did this happen? wolf ----------------------> poodle
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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
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