Chapter 4Chapter 4

Evolution and Evolution and BiodiversityBiodiversity

ORIGINS OF LIFEORIGINS OF LIFE

1 billion years of chemical change to form the 1 billion years of chemical change to form the first cells, followed by about 3.7 billion years first cells, followed by about 3.7 billion years of biological change. of biological change.

Figure 4-2Figure 4-2

Biological Biological EvolutionEvolution

This has led to This has led to the variety of the variety of species we species we find on the find on the earth today.earth today.

Figure 4-2Figure 4-2

How Do We Know Which Organisms How Do We Know Which Organisms Lived in the Past?Lived in the Past?

FossilsFossils chemical analysischemical analysis cores drilled out of cores drilled out of

buried iceburied ice DNA analysis.DNA analysis.

Figure 4-4Figure 4-4

EVOLUTION, NATURAL EVOLUTION, NATURAL SELECTION, AND ADAPTATIONSELECTION, AND ADAPTATION

MacroevolutionMacroevolution Microevolution - brought about by mutation, Microevolution - brought about by mutation,

natural selection, gene flow, & genetic driftnatural selection, gene flow, & genetic drift Gene poolGene pool Differential reproductionDifferential reproduction Directional SelectionDirectional Selection Disruptional SelectionDisruptional Selection Stabilizing SelectionStabilizing Selection

Natural Selection and Adaptation: Natural Selection and Adaptation: Leaving More Offspring With Leaving More Offspring With

Beneficial TraitsBeneficial Traits Three conditions necessary for biological Three conditions necessary for biological

evolution:evolution: Genetic variability, traits must be heritable, trait Genetic variability, traits must be heritable, trait

must lead to must lead to differential reproductiondifferential reproduction. .

Coevolution: A Biological Arms RaceCoevolution: A Biological Arms Race

Predator and prey speciesPredator and prey species Batesian Mimicry (1 bad, 1 not)Batesian Mimicry (1 bad, 1 not) Mullerian Mimicry (many poisonous animals Mullerian Mimicry (many poisonous animals

are brightly colored)are brightly colored)

GEOLOGIC PROCESSES, CLIMATE GEOLOGIC PROCESSES, CLIMATE CHANGE, CATASTROPHES, AND CHANGE, CATASTROPHES, AND

EVOLUTIONEVOLUTION

The movement of solid (tectonic) plates The movement of solid (tectonic) plates making up the earth’s surface, volcanic making up the earth’s surface, volcanic eruptions, and earthquakes can wipe out eruptions, and earthquakes can wipe out existing species and help form new ones.existing species and help form new ones. The locations of continents and oceanic basins The locations of continents and oceanic basins

influence climate.influence climate. The movement of continents have allowed The movement of continents have allowed

species to move.species to move.

Fig. 4-5, p. 88

135 million years ago

Present65 million years ago

225 million years ago

Climate Change and Natural Climate Change and Natural SelectionSelection

Changes in climate throughout the earth’s Changes in climate throughout the earth’s history have shifted where plants and history have shifted where plants and animals can live.animals can live.

Figure 4-6Figure 4-6

ECOLOGICAL NICHES AND ECOLOGICAL NICHES AND ADAPTATIONADAPTATION

Each species in an ecosystem has a specific Each species in an ecosystem has a specific role or way of life.role or way of life. Fundamental nicheFundamental niche: the full potential range of : the full potential range of

physical, chemical, and biological conditions and physical, chemical, and biological conditions and resources a species could theoretically use.resources a species could theoretically use.

Realized nicheRealized niche: to survive and avoid : to survive and avoid competition, a species usually occupies only part competition, a species usually occupies only part of its fundamental niche.of its fundamental niche.

Generalist and Specialist Species: Generalist and Specialist Species: Broad and Narrow NichesBroad and Narrow Niches

Generalist Generalist species tolerate species tolerate a wide range of a wide range of conditions.conditions.

Specialist Specialist species can species can only tolerate a only tolerate a narrow range of narrow range of conditions.conditions.

Figure 4-7Figure 4-7

SPOTLIGHTSPOTLIGHTCockroaches: Nature’s Ultimate Cockroaches: Nature’s Ultimate

SurvivorsSurvivors 350 million years old350 million years old 3,500 different species3,500 different species Ultimate generalistUltimate generalist

Can eat almost anything.Can eat almost anything. Can live and breed almost Can live and breed almost

anywhere.anywhere. Can withstand massive Can withstand massive

radiation.radiation.

Figure 4-AFigure 4-A

Specialized Feeding NichesSpecialized Feeding Niches

Resource partitioning reduces competition Resource partitioning reduces competition and allows sharing of limited resources.and allows sharing of limited resources.

Figure 4-8Figure 4-8

Evolutionary DivergenceEvolutionary Divergence

Each species has a Each species has a beak specialized to beak specialized to take advantage of take advantage of certain types of certain types of food resource.food resource.

Figure 4-9Figure 4-9

SPECIATION, EXTINCTION, AND SPECIATION, EXTINCTION, AND BIODIVERSITYBIODIVERSITY

Speciation: A new species can arise when Speciation: A new species can arise when member of a population become isolated for member of a population become isolated for a long period of time.a long period of time. Reproductive isolation:Reproductive isolation: Temporal isolationTemporal isolation Behavioral isolationBehavioral isolation Geographic isolationGeographic isolation

Geographic IsolationGeographic Isolation

……can lead to reproductive isolation, can lead to reproductive isolation, divergence of gene pools and speciation.divergence of gene pools and speciation.

Figure 4-10Figure 4-10

Extinction: Lights OutExtinction: Lights Out

Background Background extinctionextinction

Mass ExtinctionMass Extinction Adaptive Adaptive

radiationradiation GradualismGradualism Punctuated Punctuated

EquilibriumEquilibrium FitnessFitness

The golden toad of Costa Rica’s The golden toad of Costa Rica’s Monteverde cloud forest has Monteverde cloud forest has become extinct because of become extinct because of changes in climate.changes in climate.

Figure 4-11Figure 4-11

Fig. 4-12, p. 93

Tertiary

Bar width represents relative number of living speciesEra Period

Species and families experiencing

mass extinction

Millions ofyears ago

Ordovician: 50% of animal families, including many trilobites.

Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites.

500

345

Cambrian

Ordovician

Silurian

Devonian

Extinction

Extinction

Pal

eozo

icM

eso

zoic

Cen

ozo

ic

Triassic: 35% of animal families, including many reptiles and marine mollusks.

Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites.Carboniferous

Permian

Current extinction crisis causedby human activities. Many speciesare expected to become extinctwithin the next 50–100 years.Cretaceous: up to 80% of ruling reptiles (dinosaurs); many marine species including manyforaminiferans and mollusks.

Extinction

Extinction

Triassic

Jurassic

Cretaceous

250

180

65Extinction

ExtinctionQuaternary Today

GENETIC ENGINEERING AND THE GENETIC ENGINEERING AND THE FUTURE OF EVOLUTIONFUTURE OF EVOLUTION

We have used We have used artificial selectionartificial selection to change to change the genetic characteristics of populations with the genetic characteristics of populations with similar genes through similar genes through selective breedingselective breeding..

We have used We have used genetic engineeringgenetic engineering to transfer genes to transfer genes from one species to from one species to another.another.

Figure 4-15Figure 4-15

Genetic Engineering:Genetic Engineering: Genetically Modified Organisms (GMO)Genetically Modified Organisms (GMO)

GMOsGMOs useuse recombinant recombinant DNADNA genes or portions genes or portions

of genes from of genes from different different organisms.organisms.

Figure 4-14Figure 4-14