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Unformatted text preview: Evolution and Biodiversity
Chapter 4 Key Concepts Origins of life Evolution and evolutionary processes Ecological niches Species formation Species extinction Intelligent design How Did We Become Such a Powerful Species So Quickly? Adaptive traits Human weaknesses Opposable thumbs Walk upright Intelligence Environmental impacts
Fig. 4-1, p. 63 Origins of Life Chemical evolution Biological evolution How Do We Know Which Organisms Lived in the Past? Fossil record Radiometric dating Ice cores DNA studies Fig. 4-2, p. 65 Biological Evolution of Life
Modern humans (Homo sapiens) appear about 2 seconds before midnight Recorded human history begins 1/4 second before midnight Origin of life (3.63.8 billion years ago) Fig. 4-3, p. 66 Biological Evolution Evolution Theory of evolution Microevolution Macroevolution Microevolution Gene pool Genetic variability Mutations Mutagens Natural selection Natural Selection Differential reproduction Adaptation (adaptive trait) Coevolution Ecological Niches and Adaptation Ecological niche Habitats Fundamental niche Realized niche Broad and Narrow Niches and Limits of Adaptation Generalist species Specialist species Limits of adaptation
Refer to Spotlight, p. 69 Niches of Specialist and Generalist Species Number of individuals Specialist species with a narrow niche Niche separation Generalist species with a broad niche Niche breadth Region of niche overlap Resource use Fig. 4-4, p. 68 Specialized Feeding Niches for Birds
Black skimmer seizes small fish at water surface Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Brown pelican dives for fish, which it locates from the air Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Herring gull is a tireless scavenger Ruddy turnstone searches under shells and pebbles for small invertebrates Flamingo feeds on minute organisms in mud Louisiana heron wades into water to seize small fish Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Piping plover feeds on insects and tiny crustaceans on sandy beaches Fig. 4-5, p. 68-69 Cockroaches: Nature's Ultimate Survivors Fig. 4-A, p. 69 Evolutionary Divergence of Honeycreepers
Fruit and seed eaters
Greater Koa-finch Kuai Akialaoa Amakihi Kona Grosbeak Insect and nectar eaters Akiapolaau Crested Honeycreeper Maui Parrotbill Apapane Unknown finch ancestor Fig. 4-6, p. 70 Misconceptions of Evolution "Survival of the fittest" "Progress to perfection" Speciation What is speciation? Geographic isolation Reproduction isolation Geographic Isolation can Lead to Speciation Arctic Fox
Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage. Early fox population Spreads northward and southward and separates Different environmental conditions lead to different selective pressures and evolution into two different species. Gray Fox Southern population Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Fig. 4-7, p. 71 Factors Leading to Extinction Plate tectonics Climatic changes over time Natural catastrophes Human impacts Extinctions Background extinctions Mass extinctions Mass depletions Human impacts "Continental Drift" (Plate Tectonics): The Breakup of Pangaea
A AE G AN LAURASIA
GO NDW P ANA LAN D 225 million years ago 135 million years ago AM TH R NO A RI C E EURASIA H UT SO AFRICA
MAD A GASC AR IA IND E AM CA RI ANTARTICA A ALI ST R AU 65 million years ago Present Fig. 4-8, p. 72 Mass Extinctions of the Earth's Past Fig. 4-9, p. 73 Changes in Biodiversity over Geologic Time
1600 Ordovician Jurassic Carboniferous Number of families 1200 Pre-cambrain
Cretaceous Devonian Silurian Cambrian Permian Triassic Terrestrial organisms Marine organisms 400 0 3500 545 500 440 410 355 290 250 205 145 65 1.8 0 Millions of years ago Fig. 4-10, p. 74 Quaternary Tertiary 800 Future of Evolution Artificial selection Genetic engineering (gene splicing) Genetic modified organisms (GMOs) Cloning Ethical concerns Genetic Engineering
Phase 1 Make Modified Gene E. coli Cell Extract DNA Gene of interest
Identify and extract gene with desired trait Extract plasmid plasmid Genetically modified plasmid DNA Identify and remove portion of DNA with desired trait Remove plasmid from DNA of E. coli Insert extracted DNA (step 2) into plasmid (step3) Insert modified plasmid into E. coli Grow in tissue culture to make copies Fig. 4-11, p. 75 Genetic Engineering
Phase 2 Make Transgenic Cell E. coli A. tumefaciens (agrobacterium) Foreign DNA Host DNA Nucleus Transfer plasmid copies to a carrier agrobacterium Agrobacterium inserts foreign DNA into plant cell to yield transgenic cell Transfer plasmid to surface microscopic metal particle Use gene gun to inject DNA into plant cell Fig. 4-11, p. 75 Genetic Engineering
Phase 3 Grow Genetically Engineered Plant Transgenic cell from Phase 2 Cell division of transgenic cells Culture cells to form plantlets Transfer to soil Transgenic plants with new traits Fig. 4-11, p. 75 Genetically Engineered Mouse Fig. 4-12, p. 76 Intelligent design and creationism
1. What is creationism? What is intelligent design (ID)? The "design inference" 1. 1. The Design Inference Is there evidence of meaning or purpose? Does this purpose arise from known scientific laws? Can the pattern arise from "chance"? Is ID Science?
Logic and math : ID yes, Science yes Reliance on data: ID yes, Science yes Acceptance of unobservable phenomena: ID yes, Science no ...
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- Spring '08