UNIT 3B: BIODIVERSITY
Chapter 10, Section 2: Biodiversity at Risk
Standards: SEV1a, 1d, 1e
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What is the difference
between threatened,
endangered, & extinct?
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What are NATURAL causes
of extinction?
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What is the “6th
extinction”?
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What types of species are
prone to extinction?
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Name ________________________
___________________________- species is declining so much it is likely
to become endangered if not protected.
___________________________- species that is likely to become
extinct if not protected.
__________________________- last members of a species die.
o ______________ extinction- species is extinct in local
area/region
o ______________ extinction- species is extinct on entire planet
There have been ____ major natural mass extinctions since the
beginning of geologic time.
These are caused by
o ______________________________
o Major _________________________________________
Both caused drastic changes in ________________________.
Many species could not ________________ quickly enough so they
died.
“6th extinction” is not caused by natural events- caused by
______________.
Rate of extinction has increased by multiple of ________ since 1800.
As human population increases extinction rate also increases.
Generalist species
o _____________ populations & adapt ___________________
o NOT likely to become extinct
o Ex: ______________________________________________
Specialist species
o _______________ populations & can’t adapt easily b/c they have
_____________________________________________________
o Includes many species that ___________________-whooping
crane
o May be exploited by humans
o Ex: _________________________________________________
How do humans cause
extinctions?
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H- Habitat Destruction/Fragmentation
o Humans use land to
 ______________________
 Build ________________________________
 For _____________________________
o Using the land, we destroy & fragment animal habitats
o Causes ________% of all extinctions
o Ex: Florida Panther- range consisted of entire southeast, now
restricted to southernmost tip of Florida thanks to habitat
fragmentation. Need lots of territory to live & hunt
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I- Invasive exotic species
o ____________________- native to an area and usually limited in
number
o __________________________- not native to a particular area.
o _______________________- cause damage in a particular area.
o Invasive exotics are more successful than endemics b/c:
 Do not have ______________________________
 ____________________ endemic species for space/food
o Ex: kudzu, fire ants, zebra mussels, snakehead fish
o Invasive exotics introduced intentionally…?
 Invasive exotic _____________________ was brought to
Hawaii to get rid of another invasive species- _________.
 Rats are active at ___________________.
 Mongoose was active during the _____________.
 Instead of eating rats, mongoose ate native __________
& their ________________.
 Epic Fail.
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P- Pollution
o Types of pollutants
 ________________________________
 Drugs & other chemicals
 Burning _____________________- makes water
___________ for fish & amphibians
 ________________________
 Ex: DDT- pesticide used in 1950’s
 Caused egg shells of bald eagles to become too
___________________.
 Mother birds sat on eggs to incubate and they
would break.
 Main reason bald eagles were on endangered
species list.
 DDT banned in _____________ and now bald
eagle populations have recovered.
Remember H-I-P-P-O
These are the 5 ways
humans cause extinctions.
H- Habitat Destruction
I- Invasive exotic species
P- Pollution
P- Poaching
O- Overharvesting
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P- Poaching
o ______________________- illegal hunting of an organism
o ________________ are established in many countries to prevent
illegal hunting.
o In developing countries these organisms may be a source of
_________________________________________________.
o Should they stop killing “pretty animals” or feed their families
with them?
o Ex: all large cats (skin, teeth gallbladders), elephants (ivory
tusks), rhinos (horns for “medicine”)
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O- Overharvesting
o In the past, catching fish or whales was done with small boats,
harpoons, rods/reels
o Now _______________________ enables us to locate & harvest
them in large quantities.
o Ex: most commercial fish are overharvested
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Tropical rainforest
o Cover less than __% of land but have ____% of world’s species
o Still many ___________ species that may benefit man (medicine)
Coral reefs & coastal ecosystems
o Invertebrate “____________________”- many mollusks &
crustaceans lay eggs here & babies grow up here
o Used for ____________________________________________
o Protect mainland from ________________________________
o Not well protected by laws- ____________________________
Islands
o Have distinct & limited number of species
o Very ________________________ to disturbances by people
How do humans cause
extinctions? (cont’d)
Remember H-I-P-P-O
These are the 5 ways
humans cause extinctions.
H- Habitat Destruction
I- Invasive exotic species
P- Pollution
P- Poaching
O- Overharvesting
What regions have the
most critical levels of
biodiversity?
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What is a biodiversity
hotspot?
Biodiversity hotspots
o The most threatened areas of high species diversity.
o Have high number of _________________ species and
___________________ by human activities
o Most have lost _____% of their original habitat thanks to human
encroachment.
o Ex: Madagascar (see map)
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Are any biodiversity
hotspots in U.S.?
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Yes!
Some of our hotspots:
o FL Everglades
o Midwestern Prairies
o CA coastal region
o Pacific northwest rainforest
o Hawaii
Organisms threatened by
o Land use for ___________________________________
o ________________ construction
o Overuse of ____________________
o ______________________