Chapter 4Chapter 4

Evolution and Evolution and BiodiversityBiodiversity

EvolutionEvolution MicroevolutionMicroevolution

Change over time in genetic make up of a Change over time in genetic make up of a speciesspecies

Macroevolution (biological evolution) Macroevolution (biological evolution) Change over time from one organism to Change over time from one organism to

another another Theory of EvolutionTheory of Evolution

MacroevolutionMacroevolution Natural selection Natural selection

When talking about EvolutionWhen talking about EvolutionPlease rememberPlease remember

Not Not everything everything you read you read about about Evolution is Evolution is true. true.

There is a There is a lack of lack of evidence to evidence to support support Biological Biological Evolution.Evolution.

When talking about EvolutionWhen talking about EvolutionPlease rememberPlease remember

A belief in evolution A belief in evolution undermines the Bible and undermines the Bible and Christianity as a whole. Christianity as a whole.

Chapter 4Chapter 4

Natural Selection and Natural Selection and BiodiversityBiodiversity

Why Should We Care About Why Should We Care About Biodiversity? Biodiversity?

Biodiversity provides us with:Biodiversity provides us with: Natural Resources (food water, wood, Natural Resources (food water, wood,

energy, and medicines)energy, and medicines) Natural Services (air and water Natural Services (air and water

purification, soil fertility, waste purification, soil fertility, waste disposal, pest control)disposal, pest control)

Aesthetic pleasureAesthetic pleasure

NATURAL SELECTION AND NATURAL SELECTION AND ADAPTATIONADAPTATION

Natural selection involves the change in Natural selection involves the change in a population’s genetic makeup through a population’s genetic makeup through successive generations.successive generations. genetic variabilitygenetic variability Mutations: random changes in the Mutations: random changes in the

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

I regard gene mutation as a very I regard gene mutation as a very logical and possible occurrence but logical and possible occurrence but

I do not think that it is, in view of I do not think that it is, in view of the stability of the gene, as the stability of the gene, as

important a factor in speciation as important a factor in speciation as its proponents contend. I would its proponents contend. I would also like to emphasize that there also like to emphasize that there are other methods of speciation are other methods of speciation

such as polyploidy and such as polyploidy and hybridizationhybridization

Irving W. Knobloch, Ph.DIrving W. Knobloch, Ph.D

"It may, in short, be stated that no "It may, in short, be stated that no mutation has ever occurred in the mutation has ever occurred in the progress of genetic work which is progress of genetic work which is

fully viable and behaves as a fully viable and behaves as a dominant to the wild-type dominant to the wild-type

condition. That any have given condition. That any have given rise to changes which could be of rise to changes which could be of survival value in nature appears survival value in nature appears

highly doubtful". E. B. Ford, highly doubtful". E. B. Ford, Mendelism and Evolution, Mendelism and Evolution, Dial Press, N. Y., Dial Press, N. Y., 193L193L

"Mutation changes one gene at a "Mutation changes one gene at a time; simultaneous mutation of time; simultaneous mutation of

masses of genes is unknown. On the masses of genes is unknown. On the other hand, species differ from each other hand, species differ from each other usually in many genes; hence, other usually in many genes; hence,

a sudden origin of a species by a sudden origin of a species by mutation, in one thrust, would mutation, in one thrust, would

demand a simultaneous mutation of demand a simultaneous mutation of numerous genes." numerous genes."

Theodosius Dobzhansky, Theodosius Dobzhansky, Genetics and the Origin of Species, Genetics and the Origin of Species, 2nd Ed., Columbia Univ. 2nd Ed., Columbia Univ.

Press, Press, 19411941

"Although a great many species "Although a great many species have been studied, it must be have been studied, it must be admitted that most of them are admitted that most of them are not in a “mutating” condition. not in a “mutating” condition.

Thus if mutation is not a general Thus if mutation is not a general phenomenon, it can have but phenomenon, it can have but

slight significance as a means of slight significance as a means of species formation" species formation"

Arthur W. Haupt,Arthur W. Haupt,  Fundamentals of Biology, Fundamentals of Biology, McGraw Hill Book Co., N. Y., McGraw Hill Book Co., N. Y., 1928.1928.

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

New species arise through hybridization.New species arise through hybridization. Occurs when individuals of 2 distinct Occurs when individuals of 2 distinct

species crossbreed to produce a fertile species crossbreed to produce a fertile offspring.offspring.

Some species (mostly microorganisms) Some species (mostly microorganisms) can exchange genes without sexual can exchange genes without sexual reproduction.reproduction. Horizontal gene transferHorizontal gene transfer

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

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

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

Beneficial TraitsBeneficial Traits Three conditions are necessary :Three conditions are necessary :

Genetic variabilityGenetic variability traits must be heritabletraits must be heritable trait must lead to trait must lead to differential differential

reproductionreproduction. .

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

Beneficial TraitsBeneficial Traits An adaptive trait is any heritable trait that An adaptive trait is any heritable trait that

enables an organism to survive through enables an organism to survive through natural selection and natural selection and

reproduce better under prevailing reproduce better under prevailing environmental conditions.environmental conditions.

Natural Selection: A Biological Arms Natural Selection: A Biological Arms RaceRace

Interacting species can engage in a back Interacting species can engage in a back and forth genetic contest in which each and forth genetic contest in which each gains a temporary genetic advantage gains a temporary genetic advantage over the other.over the other. This often happens between predators This often happens between predators

and prey species.and prey species.

Limits on Adaptation through Limits on Adaptation through Natural SelectionNatural Selection

A population’s ability to adapt to new A population’s ability to adapt to new environmental conditions through environmental conditions through natural selection is limited by its gene natural selection is limited by its gene pool and how fast it can reproduce.pool and how fast it can reproduce. Humans have a relatively slow Humans have a relatively slow

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

Common Myths about Natural Common Myths about Natural SelectionSelection

Natural selection is not about survival of the Natural selection is not about survival of the fittest.fittest.

It is about the most descendants.It is about the most descendants. Organisms do not develop certain traits Organisms do not develop certain traits

because they need them.because they need them. It is a completely random process.It is a completely random process. There is no such thing as genetic There is no such thing as genetic

perfection.perfection.

SPECIATION, EXTINCTION, AND SPECIATION, EXTINCTION, AND BIODIVERSITYBIODIVERSITY

Endemic speciesEndemic species Found in only one placeFound in only one place Vulnerable to extinctionVulnerable to extinction

Background extinctionBackground extinction Low rate of disappearanceLow rate of disappearance

Mass extinctionMass extinction Significant rise in disappearance rate Significant rise in disappearance rate

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

SPECIATION, EXTINCTION, AND SPECIATION, EXTINCTION, AND BIODIVERSITYBIODIVERSITY

RichnessRichnessNumber of different species Number of different species

Evenness Evenness Relative abundance of individuals Relative abundance of individuals

within each specieswithin each 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 : the full potential

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

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

ECOLOGICAL NICHES AND ECOLOGICAL NICHES AND ADAPTATIONADAPTATION

Native speciesNative species Normally live in the environmentNormally live in the environment

Non native speciesNon native species Accidentally introduced to the environmentAccidentally introduced to the environment Invasive or alien speciesInvasive or alien species

Indicator speciesIndicator species Provide an early warning of damage Provide an early warning of damage

ECOLOGICAL NICHES AND ECOLOGICAL NICHES AND ADAPTATIONADAPTATION

Keystone speciesKeystone species Have a large effect on types and abundance of Have a large effect on types and abundance of

other organismsother organisms Have critical roles in the environmentHave critical roles in the environment

Foundation speciesFoundation species Shape communities by creating & enhancing Shape communities by creating & enhancing

habitatshabitats

Specialized Feeding NichesSpecialized Feeding Niches

No two organisms can share the exact No two organisms can share the exact same Niche in the exact same placesame Niche in the exact same place

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

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

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?

THE FUTURE THE FUTURE

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.

How Would You Vote?How Would You Vote?

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 a. No. Human cloning will lead to

widespread human rights abuses and widespread human rights abuses and further overpopulation.further overpopulation.

b. Yes. People would benefit with longer b. Yes. People would benefit with longer and healthier lives. and healthier lives.