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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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Long time scale events that gradually create and destroy species.
Gradualism: Long time scale events that gradually create and destroy species. Charles Darwin
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Punctuated Equilibrium:
Short periods of time with “rapid” leaps in evolution. Usually after a major extinction event. Steven Gould
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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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Evolution Diversity 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: Trilobites Giant Ground Sloth of South America This species NO longer existed. What had happened to them?
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Evidence for Evolution – The Fossil Record
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What Pressures Cause Evolution ?
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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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 Selection
Selective Breeding To Enhance Desired Traits Among Stock or Crops Dogs, horses, fruits, corn etc..
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Artificial Selection
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Wild Mustard was artificially selected to become broccoli!
Yum!
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Natural Selection Cannot Be Seen Directly
It Can Only Be Observed As Changes In A Population Over Many Successive Generations Radiation Fossil 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 Record
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Descent With Modification
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Similarities in DNA Sequence
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Evolution of pesticide resistance in response to selection
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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 Theory Variation
Individual Organisms In Nature Differ From One Another. Some Of This Variation Is Inherited Overproduction Organisms In Nature Produce More Offspring Than Can Survive, And Many Of These Offspring Do No Reproduce
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Darwin's Theory Competition
More Organisms Are Produced Than Can Survive, Members Of Each Species Must Compete For Limited Resources Adaptation Each Organism Is Unique, Each Has Different Advantages & Disadvantages In The Struggle For Existence
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Darwin's Theory Natural Selection
Individuals Best Suited To Their Environment Survive & Reproduce Successfully – Passing Their Traits To Their Offspring. Speciation Species 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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