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Chapter 10:
Biodiversity
Chapter 10 Biodiversity Big Ideas
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The huge diversity of life on
Earth is critical to all species.
Some factors about species make
them prone to extinction.
Human activities are causing
large numbers of species to go
extinct.
Section 1: What is biodiversity?
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How many species live on Earth?
Describe the types of biodiversity.
Explain the importance of biodiversity.
Terms: biodiversity, gene, keystone
species, ecotourism
Biodiversity
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Biodiversity: the
number of
different species
in a given area
Tropical rain
forests
What factors
lead to
biodiversity?
• About 1.7 million species are known
•Estimated to be greater than 10 million
•Why so many unknown?
Biodiversity
Which species rule the world?
Levels of Biodiversity
Species Biodiversity:
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differences between
populations
number of different
species in an area
Ecosystem Diversity:
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how many types of
habitats or communities in
an area
Genetic Diversity:
 number of genes in all members of a population
What is a gene?
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Gene: a piece of
DNA code for a
specific trait
inherited
Tall, short,
brown eyes, etc.
Genetic Diversity among
corn
Levels of Biodiversity
Genetic
diversity:
Differences
in DNA
among
individuals
Species
diversity:
Variety of
species in a
given area
Ecosystem
diversity:
Variety of
habitats,
ecosystems,
communities
Ecosystem diversity
often leads to
species diversity and
often leads to
genetic diversity
Did You Know?
In general,
biodiversity
increases toward
the equator.
Who cares about Biodiversity?
A Variety of Answers
We Care !
Benefits of Biodiversity
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Genetic Diversity
Key To Survival
Small isolated
populations
unlikely to survive
• Genetic mutations
from inbreeding can
occur
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More diversity =
more likely to
survive
Why is genetic diversity important?
Cavendish
banana
“ The fungus Fusarium oxysporum wiped out the previous species of bananas (the
Gros Michel) in the 1950s. Now it’s back, having evolved to be able to take on the
previously resistant “back-up” species of banana — the Cavendish — that replaced
the superior Gros Michel banana after it was wiped out. “
Benefits of Biodiversity:
Ecosystem Services
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Intact environments provide ecosystem
services
•water purification and pest control
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High biodiversity increases stability of
communities and ecosystems
•enables them to perform services.
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Stable ecosystems are resistant and resilient
Benefits of Biodiversity
Keystone Species:
species that is
critical to
ecosystem
survival
• Sea Otter
• Grey Wolf
• Beaver
Keystone Species
Food Web Depends Upon Krill
Benefits of Biodiversity
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Species
Population and
Survival:
• Genetic diversity
increases chance
that some survive
environmental
pressures or
changes
Benefits of Biodiversity
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See Table 1 page 243
Medical,
Industrial,
Agricultural Uses
Food, cloths,
shelter, chemicals
and medicine
often comes from
variety of
organisms
Medical
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Medicine:
Organisms
contain
compounds
that are useful
for treating
disease
The yew tree, an original source
of Taxol, a cancer-fighting drug
Did You Know?
Of the 150 most prescribed
drugs in the United States,
118 originated in nature.
Agricultural
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Humans
benefit every
time we eat
Most foods
come from
areas of high
biodiversity
Benefits of Biodiversity
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Ethics,
Aesthetics and
Recreation
Moral, religious
purposes for all
species
Personal
enjoyment
Dolphin Tour Off NJ Beaches
Benefits of Biodiversity
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Ecotourism:
tourisms that
supports
conservation
Wildlife, birding,
wilderness hiking
People make
money by having
people view
wildlife
Section 1 Review
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How many species live on Earth?
Describe the types of biodiversity.
Explain why biodiversity is
important.
Section 2: Biodiversity at Risk
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What does it mean when a species is
threatened or endangered?
What makes some species more prone to
extinction?
What are the largest threats to biodiversity?
Which areas are likely to have high
biodiversity?
Biodiversity has increased over time, but mass
extinctions are also natural events (5 major events)
How do we get this data?
Extinctions
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Species gone forever
NORMAL
Mass Extinction:
short period of time
when large number of
species go extinct (65
MYA)
Currently in a mass
extinction…caused by
humans
Rapid climate change
• There have been five mass extinctions in Earth’s
history.
• Each time, more than 1/5 of all families and 1/2 of all
species have gone extinct.
Biodiversity at Risk
Current extinction rate
100 to 1000 times greater than
the natural background rate
In 2009, 1321 species in the
U.S. were classified as
endangered or threatened.
Endangered: At serious risk
of extinction
Threatened: Likely to
become endangered soon
through all or part of its
range
Extinctions
Certain traits make
some species more
vulnerable:
 Small populations
 Specialized
• Niche
• Habitat
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Need large range
Migrate
Valuable to humans
Species squeezed into smaller and smaller fragmented habitat
Current Extinctions
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Endangered
Species: is likely to
go extinct if
actions not taken
Threatened:
population
declining and likely
to become
endangered
Current Extinctions
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TNC estimates 1/3rd of
21,000 identified U.S.
animal and plant
species are vulnerable.
30,000 of the world’s
species and 1,200 in
U.S. are officially
endangered.
Types of endangered species worldwide
How do humans cause extinctions?
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“HIPPO”
Habitat
destruction
Invasive
species
Population
(humans)
growth
Pollution
Overharvesting
Habitat Loss/Fragmentation
Habitat
Fragmentation
Habitat fragmentation:
Patches of suitable habitat
surrounded by unsuitable
habitat
In general, larger habitat
fragments can support
greater biodiversity than
smaller fragments
Humans Causing Extinctions
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Habitat Destruction
causes 75-80%
Large creatures
need a lot of land
Invasive Species:
exotic species not
native to area can
destroy an
ecosystem
Invasive Species
Invasive species can outcompete and displace
native species
Invasive Species
CA Agricultural Checkpoints
Humans Causing Extinction
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Over-harvesting
excessive hunting
• (bison in U.S., fish,
passenger pigeon)
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Poaching: illegal
hunting
• Common in poor
countries for food,
medicines, income
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Pollution air, water,
land
• DDT, drugs, chemicals
Causes of Extinction
Climate Change
Increasingly becoming a factor in
biodiversity loss
 Unlike the other factors, climate change
has a potential global effect on
biodiversity
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Areas of Critical Biodiversity
Tropical Rain
Forests
 Coral Reefs
 Coastal
Ecosystems
 Islands
Why these
areas????
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Just 2.3% of the
planet’s land
surface is home
to 50% of the
world’s plant
species and 42%
of its vertebrate
animal species.
Areas of Critical Biodiversity
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Hotspots: most
threatened areas
of high biodiversity
Roughly 25
worldwide
Madagascar
Parts of California
Caribbean
Hotspots
Large numbers of endemic species:
species native to that area
US Hotspots
California Floristic Province –
• 3488 native plants / 2124 endemic / 565 threatened or endangered
• agriculture, housing, dams, overuse of water, destructive recreation, mining
Section 2 Review
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What does it mean when a species is
threatened or endangered?
What makes some species more prone to
extinction?
What are the largest threats to biodiversity?
What areas are likely to have high
biodiversity?
Section 3: Future of Biodiversity
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List and describe efforts to save
individual species
Explain the advantages of protecting
entire ecosystems rather than
individual species
Describe the main parts of the
Endangered Species Act
Saving Individual Species
Captive Breeding
Programs: breeding
species in captivity
with hopes of
reintroducing into
native habitats
Germ Plasm: saving
genetic material for
possible future use
(seeds ,sperm, eggs,
DNA)
Zoos &Aquariums, Wildlife Parks & Gardens
Saving Individual Species
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Does little to
preserve species
Captive individuals
may not survive in
wild
Small populations
have difficult time
with inbreeding,
diseases
Last resorts
Preserving Habitat and Ecosystems
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Most effective way
to save a species is
protect its habitat
Some species
require large areas
What about when
they leave
protected areas?
(Wolves in
Yellowstone
Best way to protect
individual species is
to protect all species
in the ecosystem
Legal Protections
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Many countries
have laws to protect
wildlife
Some weak
Some strong
U.S. law
Endangered Species
Act (ESA) one of
the strongest
ESA
Endangered Species
Act
 Passed 1973
 Protect plant and
animals in danger of
extinction
 List created of those
threatened and
endangered
 Currently ~1400
listed
 2000 total worldwide
ESA
•Forbids
governments
and citizens
from harming
listed species
and habitats
•Forbids
trade in
products
made from
listed species
ESA
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Spotted Owl
Protects listed
species from harm
No development
that harms listed
species
What does that all
mean?
Can a Shopping
Mall be built where
listed species lives?
ESA
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Species recovery plan
must be made
Habitat Conservation
Plans: plans to
protect or restore
species habitat
Why do you think
ESA may be
controversial?
Who would not like
this law?
ESA
ESA:
 1973-2010: 92 to
~1400 species listed
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54 Species removed
(26 recovery, 10
extinctions, 18 errors,
rest discovered more)
60% plants, 40%
animals
TNC says 1/3rd of all
U.S. species…30,000
not 1,260
NJ ESA List
http://www.state.nj.us/d
ep/fgw/tandespp.htm
Wildlife Corridors
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Connect habitat
fragments
enabling onceisolated
populations to
interbreed
Interbreeding
increases genetic
diversity
Yellowstone to Yukon
Internationally
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International Union for the
Conservation of Nature &
Natural Resources (IUCN)
• Red List of worldwide
endangered species
• CITES Treaty 1989
(Convention on
International Trade of
Endangered Species)
• Illegal to trade
endangered species
Ivory Tusks
Internationally
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Much more difficult
among may poorer
countries
International treaties
hard to ratify, verify
• The Biodiversity Treaty
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Oceans of particular
concern
Private conservation
efforts often more
effective (WWF,TNC,CI)
• http://animal.discovery.com/tv/whalewars/
Section 3 Review
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List and describe efforts to save
individual species.
Explain the advantages of protecting
entire ecosystems rather than
individual species.
Describe the main parts of the
Endangered Species Act.
Terms: Endangered Species Act,
habitat conservation plans, CITES
Chapter 10 Biodiversity Review
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There is a huge diversity of life
on Earth that is critical to all
species. .
There are some factors about
species that make them prone to
extinction.
Human activities are causing
large numbers of species to go
extinct.