g. tyler miller scott e. spoolman miller/spoolman …

© Cengage Learning 2015

LIVING IN THE ENVIRONMENT, 18eG. TYLER MILLER • SCOTT E. SPOOLMAN


LIVING IN THE ENVIRONMENT 17THMILLER/SPOOLMAN

CHAPTER 4

Biodiversity and Evolution


• Populations evolve through mutations in genes

– Certain genetic traits enhance individuals

ability to produce offspring with these traits

• Human activities are degrading biodiversity

– Hastening the extinction of species

– Disrupting habitats needed for development

of new species

• Each species plays a specific ecological role

(its ecological niche) in the ecosystem where it

is found

Three Big Ideas


• 400 known species

• 6 deaths per year from shark attacks

• 79-97 million sharks killed every year

– Fins

– Organs, meat, hides

– Fear

– 32% shark species threatened with extinction

• Keystone species

• Cancer resistant

Core Case Study: Why Should We Protect

Sharks?

Threatened Sharks

Fig. 4-1, p. 80


• Concept 4-1 The biodiversity found in genes, species,

ecosystems, and ecosystem processes is vital to

sustaining life on earth.

• Biological diversity or biodiversity is the variety of

the earth’s species

• or varying life forms, the genes they contain, the

ecosystems in which they live, and the ecosystem

processes of energy flow and nutrient cycling that

sustain all life

4-1 What Is Biodiversity and Why

Is It Important?


• Species: set of individuals who can mate and

produce fertile offspring

• 8 million to 100 million species

• 1.9 million identified

• Unidentified are mostly in rain forests and oceans

Biodiversity Is a Crucial Part of the Earth’s

Natural Capital (1)


• Species diversity the number and abundance of species

present in different communities.

• Genetic diversity the variety of genetic material within a

species or a population

• Ecosystem diversity

– Biomes: regions with distinct climates/species

• Functional diversity the biological and chemical processes

such as energy flow and matter recycling needed for the

survival of species, communities and ecosystems

• Ecological Diversity the variety of terrestrial and aquatic

ecosystems found in an area or on the earth

Biodiversity Is a Crucial Part of the Earth’s

Natural Capital

© Cengage Learning 2015Fig. 4-2, p. 79

Functional Diversity The biological and chemical processes such as energy flow and matter recycling needed for the survival of species, communities, and ecosystems.

Ecological Diversity The variety of terrestrial and aquatic ecosystems found in an area or on the earth.

Genetic Diversity The variety of genetic material within a species or a population.

Species Diversity The number and

abundance of species present in different

communities.


Classifying Homo Sapiens

Supplement 5, Fig. 2, p. S19

Genetic Diversity

Fig. 4-4, p. 83


Major Biomes

Fig. 4-4, p. 81

DenverBaltimore

San

FranciscoLas

Vegas St. Louis

Coastal

mountain

ranges

Sierra

Nevada

Great

American

Desert

Rocky

Mountains

Great

Plains

Mississippi

River Valley

Appalachian

Mountains

Coastal

chaparral

and scrub

Coniferous

forest

Desert Coniferous

forest

Prairie

grassland

Deciduous

forest


• Bad rep: sting us, bite us, spread disease, eat our

food, invade plants

• Pollination: lets flowering plants reproduce sexually

• Free pest control: insects eat other insects

• We need insects more than they need us

Science Focus: Have You Thanked the

Insects Today?


• Loved bugs as a kid

• Specialized in ants

• Widened scope to earth’s biodiversity

• Theory of island biogeography

• First to use “biodiversity” in a scientific paper

Individuals Matter: Edward O. Wilson: A

Champion of Biodiversity

Edward O. Wilson

Fig. 4-B, p. 85


• The scientific theory of evolution explains

how life on earth changes over time

through changes in the genes of

populations

• Populations evolve when genes mutate

and give some individuals genetic traits

that enhance their abilities to survive and

to produce offspring with these traits

(natural selection)

4-2 How Does the Earth’s Life Change

Over Time?


• Evidence

• Fossils

– Physical evidence of ancient organisms

– Reveal what their external structures looked like

• Fossil record: entire body of fossil evidence

• Only have fossils of 1% of all species that lived on

earth

Biological Evolution by Natural Selection

Explains How Life Changes over Time


Fossilized Skeleton of an Herbivore that

Lived during the Cenozoic Era

Fig. 4-5, p. 83

Fossilized Skeleton of an Herbivore that Lived

during the Cenozoic Era

Fig. 4-6, p. 86


• Biological evolution: how earth’s life changes over time

through changes in the genetic characteristics of

populations

– Darwin: Origin of Species

• Natural selection: individuals with certain traits are

more likely to survive and reproduce under a certain set

of environmental conditions

• Huge body of evidence

Biological Evolution by Natural Selection

Explains How Life Changes over Time

Evolution of Life on Earth

Supplement 5, Fig. 2, p. S18


• Populations evolve by becoming genetically

different

• Genetic variations

– First step in biological evolution

– Occurs through mutations in reproductive cells

– Mutations: random changes in DNA molecules

Evolution by Natural Selection Works

through Mutations and Adaptations (1)


• Natural selection: acts on individuals

–Second step in biological evolution

–Adaptation may lead to differential

reproduction

–Genetic resistance: ability of one or more

members of a population to resist a

chemical designed to kill it

Evolution by Natural Selection Works

through Mutations and Adaptations

Evolution by Natural Selection

Fig. 4-7, p. 87


• Strong opposable thumbs

• Walk upright

• Complex brain

Case Study: How Did Humans Become

Such a Powerful Species?


• Adaptive genetic traits must precede

change in the environmental

conditions

• Reproductive capacity

–Species that reproduce rapidly and

in large numbers are better able to

adapt

Adaptation through Natural Selection Has

Limits


1. “Survival of the fittest” is not “survival of

the strongest”

2. Organisms do not develop traits out of

need or want

3. No grand plan of nature for perfect

adaptation

Three Common Myths about Evolution

through Natural Selection


• Tectonic plates affect evolution and the

location of life on earth

– Locations of continents and oceans have

shifted through geologic time

– Species physically move, or adapt, or form

new species through natural selection

• Earthquakes – separate and isolate

populations

• Volcanic eruptions – destroy habitats

Geologic Processes Affect Natural

Selection

225 million years ago 135 million years ago

65 million years ago Present

Stepped Art

Fig. 4-8, p. 89


• Ice ages followed by warming

temperatures

• Collisions between the earth and

large asteroids

–New species

–Extinctions

Climate Change and Catastrophes Affect

Natural Selection


Changes in Ice Coverage in the Northern

Hemisphere During the last 18,000 Years

18,000 years

before

present

Northern

Hemisphere Ice

coverage

Modern day

(August)

Legend

Land above sea level

Sea ice

Continental ice

Fig. 4-10, p. 87


• Temperature range: supports life

• Orbit size: moderate temperatures

• Liquid water: necessary for life

• Rotation speed: sun doesn’t overheat surface

• Size: gravity keeps atmosphere

Science Focus: Earth Is Just Right

for Life to Thrive


• As environmental conditions change, the

balance between formation of new species

and extinction of existing species

determines the earth’s biodiversity

• Human activities can decrease

biodiversity:

– By causing the extinction of many species

– By destroying or degrading habitats needed

for the development of new species

4-4 How Do Speciation, Extinction, and

Human Activities Affect Biodiversity?


• Speciation: one species splits into two or more

species

• Geographic isolation: happens first; physical

isolation of populations for a long period

• Reproductive isolation: mutations and natural

selection in geographically isolated populations

lead to inability to produce viable offspring when

members of two different populations mate

How Do New Species Evolve?

Fig. 4-10, p. 91

Arctic Fox

Adapted to cold through

heavier fur, short ears,

short legs, and short

nose. White fur matches

snow for camouflage.

Northern

population

Early fox

population

Spreads northward and southward and separates

Different environmental

conditions lead to different

selective pressures and

evolution into two different

species.

Southern

population

Adapted to heat through

lightweight fur and long

ears, legs, and nose,

which give off more heat.

Gray Fox


• Extinction

– Biological extinction: entire species seize to exist

– Local extinction: extinction of a species over large

region

• Endemic species

– Found only in one area

– Particularly vulnerable

• Background extinction: typical low rate of extinction

• Mass extinction: 3-5 over 500 million years

Extinction is Forever

Golden Toad of Costa Rica, Extinct

Fig. 4-11, p. 92


• Artificial selection to change the genetic

characteristics of populations with similar genes. In

this process, we select one or more desirable genetic

traits in the population of a plant or animal such as a

type of wheat, fruit

Use selective breeding/crossbreeding

• Genetic engineering, is the alteration of an organism’s

genetic material, by adding, deleting, or changing

segments of its DNA to produce desirable traits or to

eliminate undesirable ones.

Science Focus: Changing the Genetic

Traits of Populations


• Consider

–Ethics

–Morals

–Privacy issues

–Harmful effects

Fig. 4-C, p. 92

Desired trait (color)

Cross breeding

ApplePear

Offspring

Best result

Cross breeding

New offspring

Desired

result

Genetically Engineered Mice

Fig. 4-D, p. 92


• Species diversity

– Number and variety of species in a given

area

• Species richness

– The number of different species in a given

area

• Species evenness

– Comparative number of individuals of each

species present

Species Diversity Includes Variety and

Abundance


• Diversity varies with geographical location

• The most species-rich communities

– Tropical rain forests

– Coral reefs

– Ocean bottom zone

– Large tropical lakes

Species Diversity: Variety, Abundance of

Species in a Particular Place (2)


• Species richness

–Increases productivity and stability

or sustainability

–Provides insurance against

catastrophe

• How much species richness do you

think is needed?

Species-Rich Ecosystems Tend to Be

Productive and Sustainable

Variations in Species Richness and Species

Evenness

Fig. 4-12, p. 93


• Species equilibrium model, theory of island

biogeography

– Rate of new species immigrating should balance

with the rate of species extinction

• Island size and distance from the mainland

need to be considered

• Edward O. Wilson

Science Focus: Species Richness

on Islands


• Ecological niche, niche

– Pattern of living: everything that affects survival and

reproduction

– Water, space, sunlight, food, temperatures

• Generalist species

– Broad niche: wide range of tolerance

• Specialist species

– Narrow niche: narrow range of tolerance

Each Species Plays a Unique Role

in Its Ecosystem

© Cengage Learning 2015Fig. 4-15, p. 92

Specialist species

with a narrow niche

Generalist species

with a broad niche

Niche

breadth

Region of

niche overlap

Nu

mb

er

of

ind

ivid

uals

Resource use

Niche

separation

Specialist Species and Generalist Species Niches


• 1600 to 3000 Pandas left in the wild

• Pandas need bamboo

–Makes it a specialist species

–Habitat is currently being destroyed

• Low reproductive rate

–Females give birth to 1 or 2 cubs every

2-3 years

Case Study: The Giant Panda – A Highly

Endangered Specialist


Brown pelican

dives for fish,

which it locates

from the air

Herring

gull is a

tireless

scavenger

Ruddy

turnstone

searches

under shells

and pebbles

for small

invertebrates

Black skimmer

seizes small fish

at water surface

Avocet sweeps bill

through mud and

surface water in

search of small

crustaceans,

insects, and seeds

Dowitcher probes

deeply into mud in

search of snails,

marine worms, and

small crustaceans

Flamingo

feeds on

minute

organisms

in mud

Scaup and other

diving ducks

feed on

mollusks,

crustaceans,

and aquatic

vegetation

Louisiana

heron wades

into water to

seize small

fish

Oystercatcher feeds

on clams, mussels,

and other shellfish

into which it pries

its narrow beak

Knot (sandpiper)

picks up worms

and small

crustaceans left

by receding tide

Piping plover

feeds on insects

and tiny

crustaceans on

sandy beaches

Fig. 4-16, p. 92

Specialized Feeding Niches of Various Bird Species in a Coastal Wetland


• 3500 species

• Generalists

– Eat almost anything

– Live in almost any climate

• High reproductive rates

Case Study: Cockroaches: Nature’s

Ultimate Survivors

Cockroach

Fig. 4-15, p. 96


• Each species plays a specific

ecological role called its niche

• Any given species may play one or

more of five important roles—native,

nonnative, indicator, keystone, or

foundation—in a particular ecosystem

4-6 What Roles Do Species Play in an

Ecosystem?


• Native species

• Nonnative species

• Indicator species


• Foundation species

Species Can Play Five Major Roles within

Ecosystems


• Indicator species

– Provide early warning of damage to a community

– Can monitor environmental quality

• Trout

• Birds

• Butterflies

• Frogs

Indicator Species Serve as Biological

Smoke Alarms


• Habitat loss and fragmentation

• Prolonged drought

• Pollution

• Increase in UV radiation

• Parasites

• Viral and fungal diseases

• Climate change

• Overhunting

• Nonnative predators and competitors

Case Study: Why Are Amphibians

Vanishing? (1)


• Importance of amphibians

– Sensitive biological indicators of

environmental changes

– Adult amphibians

• Important ecological roles in biological

communities

– Genetic storehouse of pharmaceutical

products waiting to be discovered

Case Study: Why Are Amphibians

Vanishing? (2)

Red-Eyed Tree Frog and Poison Dart Frog

Fig. 4-17a, p. 98



– Have a large effect on the types and

abundances of other specie

– Can play critical roles in helping sustain

ecosystems

• Pollination

• Top predators

Keystone Species Play Critical Roles in

Their Ecosystems


• The American alligator:

– Largest reptile in North America, keystone

species in its ecosystems

– 1930s – Hunted and poached

– 1967 – added to the endangered species list

– 1977 – impressive comeback

– More than a million alligators today in Florida

Case Study: A Keystone Species That

Almost Went Extinct


The American Alligator

Fig. 4-19, p. 95

American Alligator

Fig. 4-18, p. 99


• Create or enhance their habitats, which

benefit others

• Elephants

• Beavers

Foundation Species Help to Form the

Bases of Ecosystems

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