Evolution and Evolution and BiodiversityBiodiversity
Chapter 4Chapter 4
Key ConceptsKey Concepts
Origins of lifeOrigins of life
Evolution and evolutionary processesEvolution and evolutionary processes
Ecological nichesEcological niches
Species formationSpecies formation
Species extinctionSpecies extinction
How Did We Become Such a How Did We Become Such a Powerful Species So Quickly?Powerful Species So Quickly?
Strong opposable thumbsStrong opposable thumbs
Walk uprightWalk upright
IntelligenceIntelligence
Fig. 4-1, p. 63
Origin & Evolution of LifeOrigin & Evolution of Life
Chemical evolution Chemical evolution - - 1st billion yrs1st billion yrsorganic molecules, biopolymers & chemical organic molecules, biopolymers & chemical rxns needed for formation of first cells rxns needed for formation of first cells (Age of Earth = 4.6 billion years)(Age of Earth = 4.6 billion years)
Biological evolution Biological evolution - - first life 3.7 bya first life 3.7 bya (prokaryotes)(prokaryotes)
““Populations - not individuals - evolve by Populations - not individuals - evolve by becoming genetically different.becoming genetically different.””
Animation- Chemical EvolutionAnimation- Chemical Evolution
Stanley Miller's experiment animation
Fig. 4-3, p. 66
Modern humans(Homo sapiens)appear about2 secondsbefore midnight
Recorded humanhistory begins1/4 secondbefore midnight
Origin of life(3.6–3.8 billionyears ago)
Biological Evolution of LifeBiological Evolution of Life
How Do We Know Which How Do We Know Which Organisms Lived in the Past?Organisms Lived in the Past?
Fossil recordFossil record
Radiometric datingRadiometric dating
Ice coresIce cores
DNA studies DNA studies
Fig. 4-2, p. 65
Biological EvolutionBiological Evolution
EvolutionEvolution= = change in populations genetic makeup over change in populations genetic makeup over time time ((““Populations - not individuals - evolve by becoming genetically different.Populations - not individuals - evolve by becoming genetically different.””))
““TheoryTheory”” of evolution of evolution= = All species descended from earlier, All species descended from earlier, ancestral speciesancestral species
MicroevolutionMicroevolution= = small genetic changes in a populationsmall genetic changes in a population
MacroevolutionMacroevolution= long-term, large scale = long-term, large scale evolutionary changes (speciation, extinction)evolutionary changes (speciation, extinction)
Natural SelectionNatural Selection DefinitionDefinition: : Process where particular beneficial Process where particular beneficial
trait is reproduced in succeeding generations more trait is reproduced in succeeding generations more than other traitsthan other traits
Three ConditionsThree Conditions::1. Genetic 1. Genetic VariabilityVariability2. Trait must be inherited (2. Trait must be inherited (selectionselection occurs) occurs)3. Differential 3. Differential ReproductionReproduction - - individuals w/ trait individuals w/ trait have more offspringhave more offspring
AdaptationsAdaptations
StructuralStructural- coloration, mimicry, protective, gripping- coloration, mimicry, protective, gripping
Physiological Physiological - hibernate, chemical- hibernate, chemical
Behavioral Behavioral - ability to fly, migrate- ability to fly, migrate
Change in moth population animation
AnimationAnimation
“Genes mutate, individuals are selected, and populations evolve.”
Adaptive trait interaction
AnimationAnimation
Ecological Niches and Ecological Niches and AdaptationAdaptation
Ecological nicheEcological niche = occupation (role)= occupation (role)
HabitatsHabitats = address= address
Fundamental niche Fundamental niche = no competition= no competition
Realized niche Realized niche = with competition= with competition
Specialized Feeding Niches for Specialized Feeding Niches for BirdsBirds
Black skimmerseizes small fishat water surface
Flamingofeeds on minuteorganismsin mud
Scaup and otherdiving ducks feed onmollusks, crustaceans,and aquatic vegetation
Brown pelican dives for fish,which it locates from the air
Avocet sweeps bill throughmud and surface water in search of small crustaceans,insects, and seeds
Louisiana heron wades intowater to seize small fish
Oystercatcher feeds onclams, mussels, and other shellfish into which it pries its narrow beak
Dowitcher probes deeplyinto mud in search ofsnails, marine worms,and small crustaceans
Knot (a sandpiper) picks upworms and small crustaceansleft by receding tide
Herring gull is atireless scavenger
Ruddy turnstone searchesunder shells and pebbles for small invertebrates
Piping plover feedson insects and tinycrustaceans on sandy beaches
Fig. 4-5, p. 68-69
Broad and Narrow Niches and Broad and Narrow Niches and Limits of AdaptationLimits of Adaptation
Generalist species Generalist species - - broad nichebroad niche
Specialist species Specialist species - - narrow niche, more extinction-narrow niche, more extinction-prone under changing environmental conditions. prone under changing environmental conditions.
Which is better?Which is better?
Limits of adaptation-Limits of adaptation- gene pool & reproductive gene pool & reproductive capacitycapacity
Refer to Spotlight, p. 69- cockroaches
Fig. 4-4, p. 68
Nicheseparation
Specialist specieswith a narrow niche
Generalist specieswith a broad niche
Nichebreadth
Region ofniche overlap
Niches of Specialist and Niches of Specialist and Generalist SpeciesGeneralist Species
Resource use
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AnimationAnimation
Stabilizing selection animation.
AnimationAnimation
Disruptive selection animation.
Fig. 4-6, p. 70Unknown finch ancestor
Fruit and seed eaters Insect and nectar eaters
Greater Koa-finch
Kona Grosbeak
Akiapolaau
Maui Parrotbill
Kuai Akialaoa
Crested Honeycreeper
Apapane
Amakihi
Evolutionary Divergence of Evolutionary Divergence of HoneycreepersHoneycreepers
Misconceptions of EvolutionMisconceptions of Evolution
““Survival of the fittestSurvival of the fittest””OK if: OK if: Fitness = reproductive success ≠ strongestFitness = reproductive success ≠ strongest
““Progress to perfectionProgress to perfection””
SpeciationSpeciation What is speciation?What is speciation?
Geographic isolationGeographic isolation
Reproduction isolationReproduction isolationmutation & natural selection operate independently mutation & natural selection operate independently in gene pools of geographically isolated populationsin gene pools of geographically isolated populations
original populations become genetically distinct- original populations become genetically distinct- unable to produce live, fertile offspringunable to produce live, fertile offspring
Fig. 4-7, p. 71
Spreads northwardand southwardand separates
Arctic Fox
Gray Fox
Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage.
Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat.
Different environmentalconditions lead to differentselective pressures and evolutioninto two different species.
Northernpopulation
Southernpopulation
Early foxpopulation
Geographic Isolation can Lead to Geographic Isolation can Lead to Speciation Speciation
Speciation on archipelago animation
AnimationAnimation
ExtinctionsExtinctions Background extinctionsBackground extinctions= 1-5 species per million= 1-5 species per million
Mass extinctionsMass extinctions- five previous mass extinctions: - five previous mass extinctions: 25% - 75% species go 25% - 75% species go
Mass depletionsMass depletions- > background, but < mass- > background, but < mass
Human impacts - Human impacts - 6th major mass extinction???6th major mass extinction???
Mass Extinctions of the EarthMass Extinctions of the Earth’’s Pasts Past
Fig. 4-9, p. 73
Factors Leading to ExtinctionFactors Leading to Extinction
Plate tectonicsPlate tectonics
Climatic changes over time-Climatic changes over time-mostmost
Natural catastrophesNatural catastrophes
Human impactsHuman impacts
PANGAEA
GONDWANALAND
LAURASIA
NORTH AMERICA
ANTARTICAAUSTRALIA
AFRICA
EURASIA
SO
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AM
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INDIAMADAGASCAR
225 million years ago 135 million years ago
65 million years ago Present
Fig. 4-8, p. 72
““Continental DriftContinental Drift”” (Plate Tectonics): The (Plate Tectonics): The Breakup of PangaeaBreakup of Pangaea
Fig. 4-10, p. 74
Terrestrialorganisms
Marineorganisms
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Millions of years ago
Changes in Biodiversity over Changes in Biodiversity over Geologic TimeGeologic Time
Future of EvolutionFuture of Evolution Artificial selection Artificial selection (selective breeding)(selective breeding)
Genetic engineering (gene splicing)Genetic engineering (gene splicing)
Genetic modified organisms (GMOs)Genetic modified organisms (GMOs)
CloningCloning
Ethical concernsEthical concerns
Fig. 4-12, p. 76
Genetically Engineered MouseGenetically Engineered Mouse
Mouse on right has human growth hormone gene- grows 3x faster and 2x larger
Genetic Engineering LinksGenetic Engineering LinksGenetic Engineering and Society, Lecture 1a, Honors Collegium 70A, UCLA
http://www.youtube.com/watch?v=eg19FquatGo
Watch This Lecture. Take Notes and turn in for 10 activity points
Yale University online Lectures- Genetic Engineering
http://www.youtube.com/watch?v=uUddHabtAzk&feature=relmfu
Alternative to UCLA lecture.
Future of genetic engineering - by Futurist Dr Patrick Dixon.
http://www.youtube.com/watch?v=P_UoReSgz84