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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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