Chapter 4Chapter 4

Evolution and Evolution and BiodiversityBiodiversity

Core Case StudyCore Case StudyEarth: The Just-Right, Adaptable Earth: The Just-Right, Adaptable

PlanetPlanet

3.7 billion years 3.7 billion years since life arosesince life arose

average surface average surface temperature of the temperature of the earth has remained earth has remained within the range of within the range of 10-2010-20ooCC

Figure 4-1Figure 4-1

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

Animation: Stanley Miller’s ExperimentAnimation: Stanley Miller’s Experiment

PLAYANIMATION

Fig. 4-3, p. 84

Modern humans (Homo sapiens sapiens) appear about 2 seconds before midnight

Recorded human history begins about 1/4 second before midnight

Origin of life (3.6-3.8 billion years ago)

Age of mammals

Age of reptiles

Insects and amphibians invade the land

First fossil record of animals

Plants begin invading land Evolution and

expansion of life

Animation: Evolutionary Tree of LifeAnimation: Evolutionary Tree of Life

PLAYANIMATION

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

Our knowledge about Our knowledge about past life comes from:past life comes from: FossilsFossils chemical analysischemical analysis cores drilled out of cores drilled out of

buried iceburied ice DNA and protein DNA and protein

analysisanalysis

Figure 4-4Figure 4-4

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

Biological evolution Biological evolution by by natural selection natural selection change in a population’s genetic makeup through change in a population’s genetic makeup through

successive generationssuccessive generations genetic variabilitygenetic variability MutationsMutations::

• random changes in the structure or number of DNA random changes in the structure or number of DNA molecules in a cell that can be molecules in a cell that can be inheritedinherited by offspring. by offspring.

Animation: Stabilizing SelectionAnimation: Stabilizing Selection

PLAYANIMATION

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

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

evolution:evolution: Genetic variabilityGenetic variability traits must be heritabletraits must be heritable trait must lead to trait must lead to differential reproductiondifferential reproduction

• An An adaptive trait adaptive trait is any heritable trait that enables an is any heritable trait that enables an organism to organism to survive through natural selection survive through natural selection and and reproduce better reproduce better under prevailing environmental under prevailing environmental conditions.conditions.

Survival of the FittestSurvival of the Fittest

Animation: Disruptive SelectionAnimation: Disruptive Selection

PLAYANIMATION

Animation: Moth PopulationsAnimation: Moth Populations

PLAYANIMATION

Animation: Adaptive TraitAnimation: Adaptive Trait

PLAYANIMATION

Hybridization and Gene Swapping: Hybridization and Gene Swapping: other Ways to Exchange Genesother Ways to Exchange Genes

HybridizationHybridization Can create new speciesCan create new species Occurs when individuals to two distinct species Occurs when individuals to two distinct species

crossbreed to produce fertile offspringcrossbreed to produce fertile offspring Some species (mostly microorganisms) can Some species (mostly microorganisms) can

exchange genes without sexual reproduction.exchange genes without sexual reproduction. Horizontal gene transferHorizontal gene transfer

Limits on Adaptation through Limits on Adaptation through Natural SelectionNatural Selection

Changes are limited by the population’s gene Changes are limited by the population’s gene pool and how fast it can reproduce.pool and how fast it can reproduce. Humans have a relatively slow generation time Humans have a relatively slow generation time

(decades) and output (# of young) versus some (decades) and output (# of young) versus some other species.other species.

Common Myths about Evolution Common Myths about Evolution through Natural Selectionthrough Natural Selection

Organisms do not develop certain traits Organisms do not develop certain traits because they need them.because they need them.

There is no such thing as genetic perfection.There is no such thing as genetic perfection.

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

Video: Continental DriftVideo: Continental Drift

PLAYVIDEO

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

Fig. 4-6, p. 89

Land above sea level

18,000years before present

Northern HemisphereIce coverage

Modern day(August)

Note:Modern sea ice

coveragerepresents

summer months

LegendContinental ice

Sea ice

Video: Dinosaur DiscoveryVideo: Dinosaur Discovery

From ABC News, Environmental Science in the Headlines, 2005 DVD.From ABC News, Environmental Science in the Headlines, 2005 DVD.

PLAYVIDEO

Catastrophes and Natural SelectionCatastrophes and Natural Selection

Asteroids and meteorites hitting the earth and Asteroids and meteorites hitting the earth and upheavals of the earth from geologic upheavals of the earth from geologic processes have wiped out large numbers of processes have wiped out large numbers of species and created evolutionary species and created evolutionary opportunities by natural selection of new opportunities by natural selection of new species.species.

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

Fig. 4-7, p. 91

Generalist specieswith a broad niche

Nu

mb

er o

f in

div

idu

als

Resource use

Specialist specieswith a narrow niche

Nicheseparation

Nichebreadth

Region of niche overlap

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

Fig. 4-8, pp. 90-91

Piping plover feedson insects and tinycrustaceans on sandy beaches

(Birds not drawn to scale)

Black skimmerseizes small fishat water surface

Flamingofeeds on minuteorganismsin mud

Scaup and otherdiving ducks feed on mollusks, 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 up worms andsmall crustaceans leftby receding tide

Herring gull is atireless scavenger

Ruddy turnstone searches

under shells and pebbles

for small invertebrates

Video: Frogs GaloreVideo: Frogs Galore

From ABC News, Environmental Science in the Headlines, 2005 DVD.From ABC News, Environmental Science in the Headlines, 2005 DVD.

PLAYVIDEO

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

Fig. 4-9, p. 91

Maui Parrotbill

Fruit and seed eaters Insect and nectar eaters

Kuai Akialaoa

Amakihi

Crested Honeycreeper

Apapane

Akiapolaau

Unknown finch ancestor

Greater Koa-finch

Kona Grosbeak

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. Genetic makeup changes, preventing them from Genetic makeup changes, preventing them from

producing fertile offspring with the original producing fertile offspring with the original population if reunited.population if reunited.

Animation: Speciation on an ArchipelagoAnimation: Speciation on an Archipelago

PLAYANIMATION

Animation: Evolutionary Tree DiagramsAnimation: Evolutionary Tree Diagrams

PLAYANIMATION

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

Fig. 4-10, p. 92

Different environmentalconditions lead to different selective pressures and evolution into two different species.

SouthernPopulation

Northernpopulation

Adapted to heat through lightweightfur and long ears, legs, and nose, which give off more heat.

Adapted to cold through heavier fur,short ears, short legs,short nose. White furmatches snow for camouflage.

Gray Fox

Arctic Fox

Spreadsnorthward

and southwardand separates

Early foxPopulation

Extinction: Lights OutExtinction: Lights Out

Extinction occurs Extinction occurs when the when the population population cannot adapt to cannot adapt to changing changing environmental environmental conditions.conditions.

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

Effects of Humans on BiodiversityEffects of Humans on Biodiversity

The scientific consensus is that human The scientific consensus is that human activities are decreasing the earth’s activities are decreasing the earth’s biodiversity.biodiversity.

Figure 4-13Figure 4-13

Fig. 4-13, p. 94

Marineorganisms

Terrestrialorganisms

Nu

mb

er o

f fa

mil

ies

Millions of years ago

Qu

ater

nar

y

Ter

tiar

y

Pre

-cam

bri

an

Cam

bri

an

Ord

ovi

cian

Sil

uri

an

Dev

on

ian

Car

bo

nif

ero

us

Jura

ssic

Dev

on

ian

Per

mia

n

Cre

tace

ou

s

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

Fig. 4-14, p. 95

Insert modifiedplasmid into E. coli

Phase 1Make Modified Gene

Cell

Extract DNA

E. coli

Gene ofinterest

DNA

Identify and extract gene with desired trait

Geneticallymodifiedplasmid

Identify and remove portion of DNA withdesired trait

Remove plasmidfrom DNA of E. coli

Plasmid

ExtractPlasmid

Grow in tissueculture to

make copies

Insert extracted(step 2) into plasmid

(step 3)

Fig. 4-14, p. 95

Plant cell

Phase 2Make Transgenic Cell

Transfer plasmid to surface of microscopic metal particle

Use gene gun to injectDNA into plant cell

Agrobacterium inserts foreign DNA into plant cell to yield transgenic cell

Transfer plasmid copies to a carrier agrobacterium

Nucleus

E. Coli A. tumefaciens(agrobacterium)

Foreign DNA

Host DNA

Fig. 4-14, p. 95

Cell division oftransgenic cells

Phase 3Grow Genetically Engineered Plant

Transfer to soil

Transgenic plantswith new traits

Transgenic cell from Phase 2

Culture cells to form plantlets

Fig. 4-14, p. 95

Phase 3Grow Genetically Engineered Plant

Transgenic cell from Phase 2

Cell division oftransgenic cells

Culture cells to form plantlets

Transgenic plantswith new traits

Transfer to soil

Stepped Art

Animation: Transgenic PlantsAnimation: Transgenic Plants

From ABC News, Biology in the Headlines, 2005 DVD.From ABC News, Biology in the Headlines, 2005 DVD.

PLAYANIMATION

How Would You Vote?How Would You Vote?

To conduct an instant in-class survey using a classroom response To conduct an instant in-class survey using a classroom response system, access “JoinIn Clicker Content” from the PowerLecture main system, access “JoinIn Clicker Content” from the PowerLecture main menu for Living In the Environment.menu for Living In the Environment.

Should we legalize the production of human Should we legalize the production of human clones if a reasonably safe technology for clones if a reasonably safe technology for doing so becomes available?doing so becomes available? a. No. Human cloning will lead to widespread a. No. Human cloning will lead to widespread

human rights abuses and further overpopulation.human rights abuses and further overpopulation. b. Yes. People would benefit with longer and b. Yes. People would benefit with longer and

healthier lives. healthier lives.

THE FUTURE OF EVOLUTIONTHE FUTURE OF EVOLUTION

Biologists are learning to rebuild organisms Biologists are learning to rebuild organisms from their cell components and to clone from their cell components and to clone organisms.organisms. Cloning has lead to high miscarriage rates, rapid Cloning has lead to high miscarriage rates, rapid

aging, organ defects.aging, organ defects. Genetic engineering can help improve human Genetic engineering can help improve human

condition, but results are not always condition, but results are not always predictable.predictable. Do not know where the new gene will be located Do not know where the new gene will be located

in the DNA molecule’s structure and how that will in the DNA molecule’s structure and how that will affect the organism.affect the organism.

Video: Cloned PoochVideo: Cloned Pooch

From ABC News, Biology in the Headlines, 2005 DVD.From ABC News, Biology in the Headlines, 2005 DVD.

PLAYVIDEO

Controversy Over Controversy Over Genetic EngineeringGenetic Engineering

There are a number of privacy, ethical, legal There are a number of privacy, ethical, legal and environmental issues.and environmental issues.

Should genetic engineering and development Should genetic engineering and development be regulated?be regulated?

What are the long-term environmental What are the long-term environmental consequences?consequences?

Case Study:Case Study:How Did We Become Such a Powerful How Did We Become Such a Powerful

Species so Quickly?Species so Quickly? We lack:We lack:

strength, speed, agility.strength, speed, agility. weapons (claws, fangs), protection (shell).weapons (claws, fangs), protection (shell). poor hearing and vision.poor hearing and vision.

We have thrived as a species because of We have thrived as a species because of our:our: opposable thumbs, ability to walk upright, opposable thumbs, ability to walk upright,

complex brains (problem solving).complex brains (problem solving).