Evolution and Biodiversity

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?

Adaptive traitsAdaptive traits

Human weaknessesHuman weaknesses

Opposable thumbsOpposable thumbs

Walk uprightWalk upright

IntelligenceIntelligence

Environmental impactsEnvironmental impacts

p. 67

Origins of LifeOrigins of Life

Chemical evolutionChemical evolution

Biological evolutionBiological evolution

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

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

Biological EvolutionBiological Evolution

EvolutionEvolution

Theory of evolutionTheory of evolution

MicroevolutionMicroevolution

MacroevolutionMacroevolution

MicroevolutionMicroevolution

Gene poolGene pool

Genetic variabilityGenetic variability

MutationsMutations

MutagensMutagens

Natural selectionNatural selection

Fig. 2-5 p. 33

A human body contains trillionsof cells, each with an identicalset of genes.

There is a nucleus inside eachhuman cell (except red blood cells).

Each cell nucleus has an identicalset of chromosomes, which arefound in pairs.

A specific pair of chromosomescontains one chromosome fromeach parent.

Each chromosome contains a longDNA molecule in the form of a coileddouble helix.

Genes are segments of DNA onchromosomes that contain instructionsto make proteins—the building blocksof life.

The genes in each cell are codedby sequences of nucleotides intheir DNA molecules.

Genetic Genetic MaterialsMaterials

Natural SelectionNatural Selection

Differential reproductionDifferential reproduction

Adaptation (adaptive trait)Adaptation (adaptive trait)

CoevolutionCoevolution

Ecological Niches and Ecological Niches and AdaptationAdaptation

Ecological nicheEcological niche

HabitatsHabitats

Fundamental nicheFundamental niche

Realized nicheRealized niche

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. 4-10, p. 72

Broad and Narrow Niches and Broad and Narrow Niches and Limits of AdaptationLimits of Adaptation

Generalist speciesGeneralist species

Specialist speciesSpecialist species

Limits of adaptationLimits of adaptation

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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Cockroaches: Nature’s Ultimate Cockroaches: Nature’s Ultimate SurvivorsSurvivors

Fig. 4-A, p. 69

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 fittest”Survival of the fittest”

““Progress to perfection”Progress to perfection”

SpeciationSpeciation

What is speciation?What is speciation?

Geographic isolationGeographic isolation

Reproduction isolationReproduction isolation

Fig. 4-9, p. 70

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

Factors Leading to ExtinctionFactors Leading to Extinction

Plate tectonicsPlate tectonics

Climatic changes over timeClimatic changes over time

Natural catastrophesNatural catastrophes

Human impactsHuman impacts

ExtinctionsExtinctions

Background extinctionsBackground extinctions

Mass extinctionsMass extinctions

Mass depletionsMass depletions

Human impactsHuman impacts

PANGAEA

GONDWANALAND

LAURASIA

NORTH AMERICA

ANTARTICAAUSTRALIA

AFRICA

EURASIA

SO

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INDIAMADAGASCAR

225 million years ago 135 million years ago

65 million years ago Present

Fig. 4-8, 4-9 p. 69

““Continental Drift” (Plate Tectonics): The Continental Drift” (Plate Tectonics): The Breakup of PangaeaBreakup of Pangaea

Mass Extinctions of the Earth’s PastMass Extinctions of the Earth’s Past

Fig. 4-9, p. 73

Fig. 4-10, p. 74

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Marineorganisms

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Changes in Biodiversity over Changes in Biodiversity over Geologic TimeGeologic Time

Future of EvolutionFuture of Evolution

Artificial selectionArtificial selection

Genetic engineering (gene splicing)Genetic engineering (gene splicing)

Genetic modified organisms (GMOs)Genetic modified organisms (GMOs)

CloningCloning

Ethical concernsEthical concerns

Fig. 4-11, p. 75

Phase 1Make Modified Gene

Identify and extractgene with desired trait

Identify and removeportion of DNAwith desired trait

Remove plasmidfrom DNA of E. coli

Insert extracted DNA(step 2) into plasmid(step3)

Insert modifiedplasmid into E. coli

Grow in tissueculture to

make copies

Cell

plasmid

E. coli

DNA

Geneticallymodifiedplasmid

Extract plasmid

Genetic EngineeringGenetic Engineering

Gene of interest

Extract DNA

Fig. 4-11, p. 75

Phase 2Make Transgenic Cell

Transfer plasmid copies to a carrier agrobacterium Agrobacterium inserts foreign

DNA into plant cell to yield transgenic cell

Transfer plasmidto surfacemicroscopic metalparticle

Use gene gunto inject DNAinto plant cell

A. tumefaciens(agrobacterium) Host DNA

Foreign DNA

Genetic EngineeringGenetic Engineering

E. coli

Nucleus

Fig. 4-11, p. 75

Phase 3Grow Genetically Engineered Plant

Transgenic cellfrom Phase 2

Cell division oftransgenic cells

Culture cellsto form plantlets

Transgenic plantswith new traits

Transfer to soil

Genetic EngineeringGenetic Engineering

p. 71

Genetically Engineered MouseGenetically Engineered Mouse