Download Conservation and Ecosystem Powerpoint

This Chapter Not in the Book
Conserving Biodiversity Community
and Ecosystem Ecology
Fourth Edition
BIOLOGY
Science for Life | with Physiology
Colleen Belk • Virginia Borden Maier
© 2013 Pearson Education, Inc.
Copyright © 2009 Pearson Education, Inc.
PowerPoint Lecture prepared by
Jill Feinstein
Richland Community College
1 The Sixth Extinction
 Endangered Species Act (ESA) – law passed in
1973 to protect and encourage population growth
of threatened and endangered species
 Biodiversity – the entire diversity of living
organisms in an area
 Extinction – the complete loss of a species
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1 The Sixth Extinction – Measuring Extinction
Rates
 History of life on earth has been punctuated with
five mass extinctions.
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1 The Sixth Extinction – Measuring Extinction
Rates
 Is the sixth mass extinction event
occurring now?
 Need to know the background
extinction rate
 Fossils indicate that average
species exists for ~1,000,000
years
 Estimate of background
extinction rate is 0.0001%
per year
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1 The Sixth Extinction – Measuring Extinction
Rates
 Current rate of extinction – three times more bird
and mammal species have disappeared in the last
150 years than in the previous 200 years
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1 The Sixth Extinction – The Causes of Extinction
 The most severe threats to species loss come from
four general categories:
 Loss or degradation of habitat
 Introduction of non-native species
 Overexploitation of species
 Pollution
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1 The Sixth Extinction – Habitat Destruction and
Fragmentation
 Habitat is the place where a particular species lives
and obtain resources for survival.
 As human population increases, pressure on natural
areas increases
 Species area curve measures the relationship between
the size of a natural area and the number of species it can
support.
 Habitat destruction affects all ecosystems.
 If worldwide habitat destruction continues at present rate,
as many as 25% of world’s species could become extinct.
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Animation: Tropical Deforestation And
The Species Area Curve
Click “Go to Animation” / Click “Play”
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1 The Sixth Extinction – Habitat Destruction and
Fragmentation
 Predicting extinction caused by habitat destruction
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1 The Sixth Extinction – Habitat Destruction and
Fragmentation
 Usually human activity results in habitat fragmentation
– large natural areas subdivided into smaller areas
 Large predators are threatened because they require
large home ranges.
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Animation: Habitat Destruction
And Fragmentation
Click “Go to Animation” / Click “Play”
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1 The Sixth Extinction – Habitat Destruction and
Fragmentation
 Basic rule of biological systems: energy flows in one
direction along a food in chain within an ecosystem
 The sun provides energy to the producers which are
feed on by the primary consumers who are feed
upon by the secondary consumers.
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1 The Sixth Extinction - Introduced Species
 Introduced species – nonnative species introduced to a
new area either purposely or
accidentally by human activity
 Most groups of species in an
area undergo coevolution.
 introduction of non-native
species is often destructive
because they have not
evolved with local species
 Brown tree snake, introduced
to Guam, caused many local
bird species to go extinct
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1 The Sixth Extinction – Overexploitation
 When human use of a natural resource exceeds its
reproductive rate, overexploitation occurs.
 Can occur if species is highly prized by humans,
which can spur illegal hunting
 Can also occur if species competes with humans
(i.e., wolves and ranchers)
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1 The Sixth Extinction – Pollution
 The release of poisons, toxins, excess nutrients, and
other waste products – pollution – is another threat to
biodiversity.
 Excess fertilizer runoff leads to eutrophication of
waterways
 Eutrophication is the excess growth of bacteria that depletes
oxygen from the water
 Carbon dioxide is another atmospheric pollutant, associated
with climate change
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2 The Consequences of Extinction – Loss of
Resources
 Loss of species can lead to economic
impacts for humans.
 Some biological resources harvested
directly include wood (lumber and fuel),
shellfish (protein), and algae (gelatin).
 Wild species provide biological chemicals
(medicines).
 Wild species have alleles that are not
present in domestic species, which can
increase vigor of domesticated species.
 Wild species can contribute other means
of combating pests (biological control).
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2 The Consequences of Extinction – Predation,
Mutualism, and Competition Derailed
 Species interact with one another and their
environment in complex ways, not just a simple
food chain instead as a food web.
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2 The Consequences of Extinction – Mutualism:
How Bees Feed the World
 Mutualism – relationship in which both species benefit from
their interaction, for example:
 Cleaner fish
 Fungal mycorrhizae
 Ants and acacia trees
 Bees are primary pollinators of many wild plants
 Wild bees pollinate 80% of agricultural crops in U.S.
 Bee populations are falling due to “colony collapse disorder”
 Humans benefit from mutualism, and will lose if bees go extinct
 Commensalism is a relationship where one species
benefits and the other is unaffected.
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2 The Consequences of Extinction – Predation:
How Songbirds May Save Forests
 Predator – species that survives by eating other
species
 Songbirds consume many insects
 Most insects eaten by songbirds consume plants
 Songbirds help to sustain forests
 As songbird numbers decline, damage to forests
increases
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2 The Consequences of Extinction – Competition:
How a Deliberately Infected Chicken Could
Save a Life
 A leading cause of food illness in the U.S. is
caused by Salmonella enteritidis.
 About 2 million Americans infected each year
 About 400 die each year as a result of infection
 Most common source of infection is eggs
 S. enteritidis contaminates egg when it forms in
the hen
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2 The Consequences of Extinction – Competition:
How a Deliberately Infected Chicken Could
Save a Life
 Competitive exclusion is the use of food and
space resources, making it impossible for another
species to establish itself.
 On this principle, chickens are deliberately infected
with harmless bacteria.
 Harmless bacteria establish and prevent S.
enteritidis from living in chicken’s gut thus
decreasing the number of eggs infected with S.
enteritidis.
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2 The Consequences of Extinction – Competition:
How a Deliberately Infected Chicken Could
Save a Life
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2 The Consequences of Extinction – Competition:
How a Deliberately Infected Chicken Could
Save a Life
 Competition between species can have
consequences for humans as well.
 Mosquitos, snails and tadpoles compete for same
resources in ponds
 When populations of snails and tadpoles decrease,
mosquitoes increase
 Potentially serious because mosquitoes can spread
malaria, West Nile virus, and yellow fever
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2 The Consequences of Extinction – Keystone
Species: How Wolves Feed Beavers
 Keystone species are key figures in determining
the food web of an ecosystem.
 Wolves were eradicated from Yellowstone Park in
1920s
 With wolves gone, biologists noted declines in
aspen, cottonwood, and willow trees
 Trees declined due to predation by elk
 Trees are crucial for beavers, songbirds, and fish
 With reintroduction of wolves, trees and other
species rebounded
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2 The Consequences of Extinction –Keystone
Species: How Wolves Feed Beavers
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2 The Consequences of Extinction – Disrupted
Energy and Chemical Flows
 An ecosystem is defined as all of the organisms
in a given area, along with their non-biological
enivornment.
 Energy flow - only a small portion (~10%) of the
energy in one level of a trophic pyramid can be
converted to biomass at the next level
 Diversity also affects energy flow, such as in more
diverse grasslands, more biomass is produced
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2 The Consequences of Extinction – Disrupted
Energy and Chemical Flows
 Nutrient cycling – nutrients that pass through a food
web rarely leave the system
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2 The Consequences of Extinction – Disrupted
Energy and Chemical Flows
 The soil community has an important role in
nutrient cycling.
 Decomposers return nutrients back in to the soil
for use by plants
 Introduction of non-native earthworms in NE U.S.
had dramatic impact on forest plants
 Non-native worms changed the soil community
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2 The Consequences of Extinction – Psychological
Effects
 Our experience with nature has strong psychological
effects
 Dental patients viewing landscapes showed a
decrease in blood pressure
 Hospital patients who could view trees recovered
from surgery more quickly
 Instinctive desire to commune with nature is called
biophilia
 Loss of biodiversity could make human experience
less pleasant
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3 Saving Species – Protecting Habitat
 Less than 2% of the earth’s surface contain
up to 50% of the earth’s mammal, bird,
reptile, and plant species. These areas are
biodiversity hotspots.
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3 Saving Species – Protecting Habitat
 Converting wild areas to agricultural production is
a major cause of habitat destruction.
 Ways to decrease the rate of habitat destruction
 Altering our consumption patterns can help
decrease habitat destruction
 Eating low on the food chain (less meat and dairy)
makes a difference
 Increased financial aid to developing countries can
also help
 So can slowing human population growth rate
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3 Saving Species – Protection From Environmental
Disasters
 A large population provides group protection from
environmental disaster.
 A species with a slow growth rate is at greater risk if its
numbers diminish.
 The longer a population remains small, the greater its risk.
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3 Saving Species – An Overview of Conservation
Genetics
 Genetic variability is the sum of all of the alleles
and their distribution within the species.
 Loss of genetic variability is a two-fold problem.
 Low genetic variability leads to low fitness, and is
more likely to express harmful mutant alleles.
 Rapid loss of genetic variability can lead to extinction
due to the low fitness of individuals.
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3 Saving Species – A Closer Look: Conservation
Genetics
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3 Saving Species – A Closer Look: Conservation
Genetics
 The importance of genetic variability
 When individuals are heterozygotic for many genes,
the overall effect is greater fitness.
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3 Saving Species – A Closer Look: Conservation
Genetics
 Heterozygotes can avoid deleterious effects of
recessive alleles.
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3 Saving Species – A Closer Look: Conservation
Genetics
 In a small population, individuals are more likely to
be related to their mates.
 Result can be inbreeding depression, a decline in
heterzygotes
 Because of this, cheetahs have poor quality sperm
and low rate of cub survival
 In humans, children of first cousins have lower rates
of heterozygosity and higher rates of infant mortality
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3 Saving Species - A Closer Look: Conservation
Genetics
 Small populations lose their genetic variability due
to genetic drift.
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3 Saving Species – A Closer Look: Conservation
Genetics
 The consequences of low
genetic variability in a
population
 A small population can
become stuck in a cycle
that leads to extinction.
 This is called the
extinction vortex
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3 Saving Species – A Closer Look: Conservation
Genetics
 Irish potato is a human example of the potentially
disastrous effects of low genetic diversity
 In 1850s, Irish potato crop had very low genetic
diversity
 Fungus that causes potato blight arrived in Ireland;
plants rotted in fields
 Because of crop failure, nearly 1 million Irish died of
starvation and disease
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4 Protecting Biodiversity Versus Meeting Human
Needs
 The protection of endangered species sometimes
has effects on human livelihood.
 Farmers were unable to use water for irrigation
because diversion of water would have disrupted fish
populations.
 Endangered Species Act has helped save American
alligators, peregrine falcons, and bald eagles.
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4 Protecting Biodiversity Versus Meeting Human
Needs
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Which cause of extinction poses the most serious
threat to biodiversity today?

degradation of habitat

introduction of nonnative species

overharvesting

effects of pollution
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Which cause of extinction poses the most serious
threat to biodiversity today?

degradation of habitat

introduction of nonnative species

overharvesting

effects of pollution
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Based on this graph, what would you predict would
be the result of decreasing the habitable area of an
island?

The number of species on
it would increase.

The number of species on
it would not be affected.

The number of species on
it would decrease.

There is no way to predict
what would happen.
© 2013 Pearson Education, Inc.
Based on this graph, what would you predict would
be the result of decreasing the habitable area of an
island?

The number of species on
it would increase.

The number of species on
it would not be affected.

The number of species
on it would decrease.

There is no way to predict
what would happen.
© 2013 Pearson Education, Inc.
How many square kilometers of rain forest are cut
each year in South America’s Amazon River
Basin?

1,000

5,000

10,000

20,000
© 2013 Pearson Education, Inc.
How many square kilometers of rain forest are cut
each year in South America’s Amazon River
Basin?

1,000

5,000

10,000

20,000
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Habitat fragmentation is especially threatening to
____________.

small decomposers

large plants

small herbivores

large predators
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Habitat fragmentation is especially threatening to
____________.

small decomposers

large plants

small herbivores

large predators
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Which of these terms best describes a dairy cow?

producer

primary consumer

secondary consumer

decomposer
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Which of these terms best describes a dairy cow?

producer

primary consumer

secondary consumer

decomposer
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The relationship where cleaner fish remove and
consume parasites from the bodies of larger fish is
known as __________.

parasitism

mutualism

commensalism

competition
© 2013 Pearson Education, Inc.
The relationship where cleaner fish remove and
consume parasites from the bodies of larger fish is
known as __________.

parasitism

mutualism

commensalism

competition
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True or False: An ecosystem is defined as all of the
organisms in a given area, along with their nonbiological environment.

True

False
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True or False: An ecosystem is defined as all of the
organisms in a given area, along with their nonbiological environment.

True

False
© 2013 Pearson Education, Inc.
Which of the following statements is incorrect?

Small populations are at higher risk for extinction.

Small populations are at greater risk when
individuals have low fitness due to inbreeding.

Small populations are at risk of losing genetic
variability due to genetic drift.

Small populations are more able to evolve in
response to environmental change.
© 2013 Pearson Education, Inc.
Which of the following statements is incorrect?

Small populations are at higher risk for extinction.

Small populations are at greater risk when
individuals have low fitness due to inbreeding.

Small populations are at risk of losing genetic
variability due to genetic drift.

Small populations are more able to evolve in
response to environmental change.
© 2013 Pearson Education, Inc.
Why was there a debate over the shortnose
suckers?

The shortnose suckers were aggressive towards
humans.

The shortnose suckers were beyond saving.

The human economy in the Lost River was
suffering due to the Endangered Species
Act.

The God squad was used.
© 2013 Pearson Education, Inc.
Why was there a debate over the shortnose
suckers?

The shortnose suckers were aggressive towards
humans.

The shortnose suckers were beyond saving.

The human economy in the Lost River was
suffering due to the Endangered Species Act.

The God squad was used.
© 2013 Pearson Education, Inc.
Each jacket represents an allele. Which of the
jacket pictures has the highest fitness for
responding to a changing environment?

the homozygote suit coat

the homozygte winter coat

the heterozygote with one of each jacket
© 2013 Pearson Education, Inc.
Each jacket represents an allele. Which of the
jacket pictures has the highest fitness for
responding to a changing environment?

the homozygote suit coat

the homozygte winter coat

the heterozygote with one of each jacket
© 2013 Pearson Education, Inc.