ch 4 biodiversity evolution

7/28/2019 Ch 4 Biodiversity Evolution

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Biodiversity and Evolution

Chapter 4


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Core Case Study: Why Should We Careabout the American Alligator?

Largest reptile in North America

1930s: Hunters and poachers

Importance of gator holes and nesting mounds

1967: endangered species

1977: comeback, threatened species


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The American Alligator


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4-1 Wh at Is B iod ivers i ty and Wh y Is It Im po rtant?

Con cept 4-1 The biodiversity found in genes,species, ecosystems, and ecosystem processesis vital to sustaining life on earth.


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Natural Capital: Major Components of the Earths Biodiversity


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4-2 Wh ere Do Species Co m e Fro m ?

Con cept 4-2A The scientific theory of evolutionexplains how life on earth changes over timethrough changes in the genes of populations.

Con cept 4-2B Populations evolve when genesmutate and give some individuals genetic traitsthat enhance their abilities to survive and to

produce offspring with these traits (natural selection).


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Biological Evolution by Natural SelectionExplains How Life Changes over Time

Biological evolution

Natural selection Charles Darwin Alfred Russel Wallace

Tree of Life


8/46Fig. 4-3, p. 81

CenozoicMesozoic

Paleozoic

Precambrian M i l l i o n s o

f y e a r s

a g o

First humansExtinction of dinosaurs

Plantscolonize land

Origin of multicellular organisms

Oldesteukaryotic fossils

Accumulation of O 2 in atmospherefrom photosyntheticcyanobacterium

Prokaryotes Eukaryotes

Origin of Earth

Earth cool enoughfor crust to solidify

Oldest prokaryoticfossils

AnimalsFungiPlantsProtistsArchaebacteriaEubacteria

0

500

4,500

4,000

3,500

3,000

2,500

2,000

1,500

1,000


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The Fossil Record Tells Much of theStory of Evolution

Fossils Physical evidence of ancient organisms Reveal what their internal structures looked

like

Fossil record is incomplete: why?


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Fossilized Skeleton of an Herbivore thatLived during the Cenozoic Era


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The Genetic Makeup of a PopulationCan Change

Populations evolve by becoming geneticallydifferent

Genetic variations First step in biological evolution Occurs through mutations in reproductive cells


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Individuals in Populations with BeneficialGenetic Traits Can Leave More Offspring

Natural selection: acts on individuals Second step in biological evolution Adaptation may lead to differential reproduction

Genetic resistance

When environmental conditions change,populations

Adapt Migrate Become extinct


13/46Fig. 4-5, p. 83

Most of the normalbacteria die

The geneticallyresistant bacteriastart multiplying

Eventually the

resistant strainreplaces the strainaffected bythe antibiotic

A group of bacteria,

including geneticallyresistant ones, areexposed to anantibiotic

Normalbacterium

Resistantbacterium

Stepped Art


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Adaptation through Natural SelectionHas Limits

Genetic change must precede change in theenvironmental conditions

Reproductive capacity


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Three Common Myths about Evolutionthrough Natural Selection

Survival of the fittest is not survival of thestrongest

Organisms do not develop traits out of need or want

No grand plan of nature for perfect adaptation


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4-3 How Do Geolo gic al Pro cess es and Cl im ate Change Affec t Evolu t ion ?

Con cept 4-3 Tectonic plate movements,volcanic eruptions, earthquakes, and climatechange have shifted wildlife habitats, wiped out large numbers of species, and created opportunities for the evolution of new species.


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Geologic Processes Affect NaturalSelection

Tectonic plates affect evolution and the locationof life on earth

Location of continents and oceans

Species physically move, or adapt, or form newspecies through natural selection

Earthquakes

Volcanic eruptions


18/46Fig. 4-6, p. 85

225 million years ago 135 million years ago

65 million years ago Present

Stepped Art


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Climate Change and Catastrophes AffectNatural Selection

Ice ages followed by warming temperatures

Collisions between the earth and large asteroids New species Extinction


20/46Fig. 4-7, p. 85

18,000years beforepresent

Modern day(August)

Northern HemisphereIce coverage

LegendContinental ice

Sea ice

Land above sea level


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Science Focus: Earth Is Just Rightfor Life to Thrive

Certain temperature range

Dependence on water

Rotation on its axis

Revolution around the sun

Enough gravitational mass


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4-4 Ho w Do Speciat ion , Ext inc t ion , and Hum an A ct iv i ti es A ffec t B iod ivers i ty?

Con cept 4-4A As environmental conditionschange, the balance between formation of new species and extinction of existing speciesdetermines the earths biodiversity.

Con cept 4-4B Human activities can decreasebiodiversity by causing the premature extinction

of species and by destroying or degrading habitats needed for the development of new species.


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How Do New Species Evolve?

Geographic isolation

Reproductive isolation


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Geographic Isolation Can Lead toReproductive Isolation


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Extinction is Forever

Extinction

Endemic species Particularly vulnerable


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Golden Toad of Costa Rica, Extinct

ff


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Extinction Can Affect One Species or Many Species at a Time

Background extinction

Mass extinction How numbered is debated: 3 5

S i F W H T W


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Science Focus: We Have Two Ways toChange the Genetic Traits of Populations

Artificial selection

Genetic engineering, gene splicing

Consider Ethics

Morals Privacy issues Harmful effects


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Genetically Engineered Mice


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Transferring genes into plants

4 5Wh I S i Di i dWh


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4-5 What Is Species Divers i ty an d Wh y Is It Im po rtant?

Con cept 4-5 Species diversity is a major component of biodiversity and tends to increasethe sustainability of ecosystems.

S i Di it V i t Ab d f


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Species Diversity: Variety, Abundance of Species in a Particular Place

Species diversity Species richness Species evenness

Diversity varies with geographical location Most species-rich communities

Tropical rain forests Coral reefs Ocean bottom zone Large tropical lakes

V i ti i S i Ri h d


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Variations in Species Richness andSpecies Evenness

S i Ri h E t T d t B


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Species-Rich Ecosystems Tend to BeProductive and Sustainable

Species richness seems to increase productivityand stability or sustainability

Rivet theory

4 6Wh tR l D S i Pl i


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4-6 Wh at Roles Do Species Play in Ecosys tems?

Con cept 4-6A Each species plays a specific ecological role called its niche.

Con cept 4-6B Any given species may play oneor more of five important roles native,nonnative, indicator, keystone, or foundationroles in a particular ecosystem.

Each Species Pla s a Uniq e Role


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Each Species Plays a Unique Rolein Its Ecosystem

Ecological niche, niche Pattern of living

Generalist species Broad niche

Specialist species Narrow niche

Specialist Species and Generalist


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Specialist Species and GeneralistSpecies Niches


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Cockroach


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Fig. 4-13, p. 93

Black skimmer

seizes small fishat water surfaceBlack skimmer seizes small fishat water surface

Brown pelican divesfor fish, which itlocates from the air

Avocet sweeps billthrough mud andsurface water in searchof small crustaceans,insects, and seeds

Dowitcher probesdeeply into mud insearch of snails,marine worms, andsmall crustaceans Herring gull

is a tirelessscavenger

Ruddy turnstonesearches under shells and pebblesfor smallinvertebrates

Flamingo feedson minute

organisms inmud

Scaup and other diving ducks feed

on mollusks,crustaceans, andaquatic vegetation

Louisianaheron wades

into water toseize smallfish

Oystercatcher feedson clams, mussels,

and other shellfishinto which it priesits narrow beak

Knot (sandpiper)picks up worms

and smallcrustaceansleft by recedingtide

Piping plover feeds on

insects andtinycrustaceanson sandybeaches

Niches Can Be Occupied by Native and


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Niches Can Be Occupied by Native andNonnative Species

Native species

Nonnative species; invasive, alien, or exotic

species May spread rapidly Not all are villains

Indicator Species Serve as Biological


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Indicator Species Serve as BiologicalSmoke Alarms

Indicator species Can monitor environmental quality

Trout Birds Butterflies Frogs

Case Study: Why Are Amphibians


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Case Study: Why Are AmphibiansVanishing? (1)

Habitat loss and fragmentation

Prolonged drought

Pollution

Increase in UV radiationParasites

Viral and fungal diseases

Climate change

Overhunting

Nonnative predators and competitors

Case Study: Why Are Amphibians


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Case Study: Why Are AmphibiansVanishing? (2)

Importance of amphibians Sensitive biological indicators of environmental

changes Adult amphibians

Important ecological roles in biologicalcommunities

Genetic storehouse of pharmaceutical products

waiting to be discovered

f


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Fig. 4-14, p. 94

Sexualreproduction

Adult frog(3 years) Young frog

Tadpole developsinto frog

Tadpole

Egg hatches

Organ formation

Fertilized eggdevelopment

Eggs

Sperm

Keystone Foundation Species Determine


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Keystone, Foundation Species DetermineStructure, Function of Their Ecosystems

Keystone species Pollinators Top predator

Foundation species Create or enhance their habitats, which benefit

others Elephants Beavers

Case Study: Why Should We


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Case Study: Why Should WeProtect Sharks?

Keystone species Eat dead and dying fish in the ocean Strong immune systems

Wounds do not get infected Almost never get cancer Could help humans if we understood their immune

system

ch 4 biodiversity evolution

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