Slide 1: Evolution
The change in a population’s genetics or inherited traits over time
Slide 2: The Myth
• Life originates by spontaneous generation
– Nonliving material gives rise to living material – i.e. maggots and flies spontaneously appear from rotted meat
Slide 3: Enter the Mythbusters
• Redi- disproved spontaneous generation of flies • Pasteur- disproved spontaneous generation of bacteria • How?
Slide 4: Mythbusters
• Redi
Slide 5: History continues- mid 1800s
S shaped neck:
Prevents entry Of microorganisms
Nutrient Broth: Heated to kill life
Nutrient Broth: Grew bacteria if exposed
Slide 6: SPONTANEOUS GENERATION
Slide 7: Biogenesis
Living organisms only come from other living organisms
Slide 8: Next Myth
SO WHERE DID LIFE BEGIN?
Slide 9: So… Where did life begin?
• Oparin- life began in oceans • Organic molecules formed
Slide 10: Enter the Mythbusters… Again
Miller and Urey
Slide 11: Miller and Urey
Lightning Atmosphere
Volcanoes
Rai n
Ocean
Slide 12: Miller and Urey
Organic molecules can be made
Slide 13: Why couldn’t we blow more stuff up?
This myth is true!
Slide 14: Now back to Evolution
How did we get so much biodiversity?
Slide 15: How are species formed?
• Lamarck –use and disuse
– if you don’t use it, you lose it – Variation created! – organisms pass on acquired traits – Ex. cut of mouse’s tail, offspring will have no tail
Slide 16: Darwin’s Idea
• Natural Selection • Variation already exists • Good variations = survival • Pass on good variations • Bad variations selected against
Slide 17: Let’s Investigate
DON’T BELIEVE ME
Slide 18: Choose a partner
• Each table is a group • Partners measure each other
– Height – Forearm length – Shoe Size All in cm!!!
• Create Google account at Google Docs
– Enter data into table
Slide 19: Oscar Brittany Ques Ian G. Jana Jorge Dora
Elizabeth Ty Dominique D Josh India Dominique
Jose Brett Mike Jolisa Kiniesha Mike
Jeremy Hope Jade Maria Jason Ian R.
Slide 20: In Lab Notebooks
• Title: The Clipbirds • Copy onto a clean sheet • Groups of four to five people
Slide 21: VARIETY… THE SPICE OF LIFE
Slide 22: Variety in your own class
Slide 23: O.K. So We Agree!
But how does variation help?
Slide 24: CLIPBIRD ACTIVITY
Slide 25: Choose Your Weapon… Carefully
• Select one beak type • Islands have one type of food • Eat as much as
you can!!!
• Record amount
Eaten
• Move to next island
Slide 26: Afterwards
• Enter data into Google Docs • Answer in notebook • Do you see any trends? • Was any beak better? • Was it always the same beak? • Did it matter which food it was?
Slide 27: WHY IS VARIATION GOOD?
Slide 28: Why is variation good?
Slide 29: Why is variation good?
Slide 30: Why is variation good?
Slide 31: Natural Selection
• Process by which advantageous or favorable traits become more common
Slide 32: How does natural selection work?
Slide 34: Inheritance of traits
• Thanks Mom and Dad! • Where else would you get the good looks?
Slide 35: Variation
• Creates more options for survival
Slide 36: Competition
• Best variations survive
• Fight for survival!
Slide 37: Overproduction of offspring
• Produce more offspring than can survive • Creates Competition
Slide 38: Natural Selection
Slide 39: • Given enough time • Variations build • May form a new species • Will not reproduce
Slide 40: Natural selection
• Populations evolve through natural selection • 3 main types of natural selection
1. 2. 3. Stabilizing selection Directional selection Disruptive selection
Slide 41: Stabilizing selection
• Average individual favored
Slide 42: Directional selection
• Extreme variations favored
– i.e. giraffe with longest neck
Slide 43: Disruptive Selection
• Both extremes is favorable
– Ex. light and dark shells blend in, medium are seen and eaten
Slide 44: How do new species form?
• Speciation- the evolution of new species
– Species can only reproduce with same species
• 3 ways for speciation to occur
1.Geographic isolation 2.Reproductive isolation 3.Adaptive radiation
Slide 45: Geographic Isolation
• populations separated by geography (river, mountain, etc.) • Stop reproducing become 2 different species
Slide 46: Reproductive Isolation
Slide 47: Adaptive radiation
• All from one species • Different islands = different food • Lead to variations
Slide 48: How fast does speciation occur?
• 2 timeframes for speciation
1. Graudalism 2. Puntuated equilibrium
• Both result in new species
Slide 49: Gradualism
• A steady, slow divergence
Slide 50: Punctuated Equilibrium
Slide 51: No one has ever seen a species evolve!
HOW DO WE KNOW EVOLUTION HAPPENS?
Slide 52: Evidence for Evolution
Slide 53: n mo r om sto Ce c An
Similar Structure
Diffe rent Func tions on omm e C No uctur Str
Simil ar Funct ion
Evidence for evolution
Slide 54: Evidence for Evolution
Slide 55: Similar development = common ancestor Genes from one species can be used in another Forms healthy organism!! Same genes turned on in same order!
Evidence for Evolution
Slide 56: More similarities = more related
Evidence for Evolution
Slide 57: Clearing up the issue…
• There is no goal • No top species • No final product
Slide 58: Clearing cont.
• Streamlined bodies = speed = survival • Not random • Advantageous variations = survival = reproduction • Non-random selection!
Slide 59: Clearing cont…
• Doesn’t satisfy a need
• Organisms don’t try to evolve!!
Slide 60: • Know the contributions of
– – – – – Redi Pateur Darwin Miller-Urey Oparin
For the Test
• Definition of natural selection • Evidence: How do they support evolution?
– – – – –
• Selection graphs: which traits favored?
– – – Stabilizing Directional Disruptive
Homologous and analogou Vestigial structures Fossils Embryology Biochemistry