Transcript Evolution
How did this happen? Wolf ----------------------> Poodle 1 Types of Theories Wolf ----------------------> Poodle 2 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. 3 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!4 Gradualism: Long time scale events that gradually create and destroy species. Charles Darwin 5 Punctuated Equilibrium: Short periods of time with “rapid” leaps in evolution. Usually after a major extinction event. Steven Gould 6 Parallel Evolution: Different Animals On Different Continents But Similar Adaptations To Shared Environments 7 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 8 Evolution Diversity of Life 9 History of Evolutionary Thought 10 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 11 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 12 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 13 14 Charles Darwin the Naturalist 15 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 16 HMS Beagle’s Voyage 17 Galapagos Tortoises 18 19 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? 20 Evidence for Evolution – The Fossil Record 21 Evolution Principles What Pressures Cause Evolution ? 22 Definition • Evolution is the gradual change in a population of organisms over time 23 1. Overproduction: - More offspring produced than needed. - Only a small fraction of offspring survive and reproduce. 24 2. Competition: - food, water, space and mates are limited - Competition within the species and with other species 25 3. Variation - There is variation within populations. - Individuals of a population vary in their genetic traits. - No two individuals are exactly alike. 26 4. Adaptations Because of variations some individuals are better adapted to survive in their environment “Survival of the Fittest” 27 Adaptations Those that survive and reproduce have the fittest genetic variations. 28 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. . 29 Extinctions Some species disappear due to a catastrophic event in nature (humans, asteroid, earthquake…) 30 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 31 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! 32 What Kinds of Evidence are Used to Study Evolution? 33 Selective Breeding Artificial Selection Selective Breeding To Enhance Desired Traits Among Stock or Crops Dogs, horses, fruits, corn etc.. 34 Artificial Selection 35 Wild Mustard was artificially selected to become broccoli! Yum! 36 Natural Selection Cannot Be Seen Directly It Can Only Be Observed As Changes In A Population Over Many Successive Generations Radiation Fossil Record 37 Fossil Record Earth is Billions of Years Old Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time. 38 Evidence for Evolution – The Fossil Record 39 Descent With Modification 40 Similarities in DNA Sequence 41 Evolution of pesticide resistance in response to selection 42 Homologous Body Structures Structures That Have Different Mature Forms But Develop From The Same Embryonic Tissues Strong Evidence That All FourLimbed Animals With Backbones Descended, With Modification, From A Common Ancestor Help Scientist Group Animals 43 Homologous Body Structures 44 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? 45 Same stages of embryos Which one is the Human? 46 Same stages of embryos 47 Human Fetus (5 weeks) with vestigal structures. 48 Chicken Turtle Rat 49 One more time for Darwin…. 50 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 51 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 52 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 53 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 54