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Published byAdele Sherman Modified over 9 years ago
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Evolution
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Word is used in many ways: –Cosmic evolution of the universe –Biochemical evolution of the 1 st life –Biological evolution of the species
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Outline for Notes: 1.Definition of Evolution 2.People: a)James Hutton b)Charles Lyell c)Lamark d)Charles Darwin 3.Natural Selection
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Evolution Change over time The theory explaining how modern organisms have descended from ancient organisms
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History of the Current Theory
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James Hutton (1795) – Charles Lyell (1833) Geologists Proposed –earth is millions of years old –Same processes you see now are ones that were there in the past
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James Hutton Proposed layers of rock, mountains, valleys form slowly – so earth is very old
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Charles Lyell Processes which shape the earth now must be the same ones that shaped the earth in the past
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Providence Canyon, Georgia How old is it? a) 150 yearsb) 15,000 years c) 15 million years
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Lamarck WRONG Inheritance of acquired traits Gain/lose traits through usage
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Charles Darwin Voyaged on Beagle Wrote On the Origin of the Species proposing a theory where all the different species came from: natural selection
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Example: the Galapagos turtles What kind of variations might exist in this turtle species?
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Natural Selection –Variation exists in nature –Struggle for existence – compete for resources –Survival of the fittest – the strongest survive to pass their genes on –Descent with modification – each living species has descended with changes from other species
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variation: neck length Compete for food (tall shrubs) Long necked turtles more fit long neck turtles survive to pass on the long neck trait
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Natural Selection –Variation –Struggle for existence –Survival of the fittest Which would survive best as a seed eater? Insect eater?
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This is the part that is controversial: Descent with modification
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Outline for Notes Fossils a)What is a Fossil? b)What are the Four Common Fossil Types? c)How do Fossils Form? d)How Are Fossils Dated? a)Absolute Age b)Relative Age e)What are fossil used for?
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What is a Fossil? Remains of ancient life
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4 Types of fossils Body fossils – actual parts (a tooth) Molds – hollowed out rock Casts – solid forms of plant/animal when mold fills up Prints – impressions formed in mud that harden (footprint)
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How do fossils form? 1. Animal dies and is QUICKLY buried 2. Soft body dissolves leaving a mold 3. Minerals replace bone/shells
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How are fossils dated?
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Method 1: Relative Dating Compare fossils to other fossils in layers of rock Oldest fossils are in lowest strata
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Method 2: Radioactive Dating Absolute dating based on remaining radioactive isotopes C-14 for previously living organisms that are “young” Must assume that all things have remained constant over history of earth
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Example AmountHalf-livesTime
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Fossils show change over time…
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…but they form an incomplete record of life…
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Outline for Notes: Evidences Cited for Evolution 1.Fossils 2.Homologous Structures 3.Biochemical Comparisons 4.Antibiotic Resistance
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Fossils show change over time Controversy comes with the missing links
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Homologous Structures Perform related functions in different species
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Biochemical Comparisons Compare amino acid sequences in proteins Compare nucleic acid sequences in genes
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Antibiotic Resistance Bacteria develop the ability to “resist” antibiotics
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Today: A.Rates of Evolution B.Geological Time Periods C. What does Evolution Require?
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Rates of Evolution 2 popular theories: (1) Gradualism: SLOW and steady (2) Punctuated equilibrium: long periods of no change with a sudden period of rapid change Both take a LONG time
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Geological Time Periods Mass extinctions often mark divisions
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Evolutionary Change Requires Changes in Genetic Information
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Changing the allele frequency 50/50 A selecting factor 80/20
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SPECIES evolve, not individuals
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Cladogram Diagram showing how organisms are related based on shared, derived characteristics such as feathers, hair, or scales
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Michael Behe
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Intelligent Design Bacteria flagellum 25 different proteins uses an electrochemical ion gradient to drive rotation speeds of up to 300 Hz.
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Origin of Eukaryotic Cells
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