Download Impacts on Biodiversity

IMPACTS ON BIODIVERSITY
Michaelis
Overfishing and Overhunting
 One threat to biodiversity occurs when
collapse
humans cause ecosystems to ____________
by using too many natural resources or taking
keystone species
away a ______________________.
Overfishing and Overhunting
Keystone species An organism that is
 ____________________:
necessary for keeping an ecosystem in
balance
_____________.
 Example: Sea Otter
Overfishing and Overhunting
Facts:
blubber
 Only marine mammal without ___________...
Overfishing and Overhunting
 How do they stay warm in the
cold ocean?
 Otters have the
densest fur
____________________
fur of any
mammal.
 Fur is so thick that their skin never
gets wet when they swim:
400,000 hairs per square
___________
centimeter.
Overfishing and Overhunting
 During the fur trade
humans hunted otters
almost to
extinction for their
_____________
thick warm pelts
____________________.
 By 1911 the sea otter
population had
dropped to roughly
1,000 individuals.
Overfishing and Overhunting
Sea Otter’s Niche:
sea urchins
 Eats _______________.
rocks and shells to break open
 Uses ___________________
sea urchins.
Overfishing and Overhunting
Sea Otter’s Niche:
sharks and humans
 Predators: _____________________________
seaweed to anchor
 Uses ________________________
themselves
while they eat and sleep.
How Sea Otters Keep Their
Ecosystem in Balance
sea urchin population down
 Otters keep the ___________________________.
 Sea urchins eat away at the _______
base of sea weed.
 Fish and other sea life rely on the sea weed
food and shelter
forests for _____________________________.
Overhunting Keystone Species:
How do you think the decreasing otter
population affects the ocean ecosystem?
 Otter population is DOWN
increases
 Sea Urchin Population = ______________
decreases
 Sea Weed Population = _______________
 Fish Population = ____________________
decreases
 Seal Population = ____________________
decreases
 Orca Population = ____________________
decreases
Overhunting Keystone Species:
What are the long term implications on the
food web in this situation?
Urchin Barrens
Biological Magnification
 When carnivores eat herbivores that have
contaminated with pollution
been _________________________________.
 Causes concentrations of harmful substances
to ___________________________________.
accumulate in higher trophic levels
Biological Magnification
 Class Demonstration
ppm of
 In this demo assume that 100
__________
pollutant will cause this animal to:
die
 ___________
 Make them ___________
sterile
unhealthy
 Make them very ______________
Biological Magnification
 Class Demonstration
 How many parts per million does the guppy
have?
 How many parts per million does the salmon
have?
 How many parts per million does the eagle
have?
Biological Magnification
 Class Demonstration
1. What type of organisms are affected the
most by biological magnification?
1. How do you think biodiversity will be
affected?
Invasive Species
Species that are brought to an ecosystem by
harm the ecosystem
humans and _________________________
do not have any natural predators
because they ______________________________.
Invasive Species
50,000
 _______________
exotic species live in the
U.S.
$130 billion per year spent to help undo
 _____________________
the damage they cause
nearly half
 Invasive species also threaten _____________
of the species currently protected under the
Endangered Species Act
________________________
Kudzu in Alabama
Zebra Mussels
Invasive Species – Burmese Python,
Florida
Introduced Beavers - Tierra
Del Fuego, South America
 Cane Toad Video
Invasive Species
Rats in Hawaii
Example: ___________________________
I’iwi Birds are ________________.
native to Hawaii They are an
________________________.
endangered species
face
I’iwi are one of many Hawaiian Birds that _____
extinction due to invasive species.
__________________________________
Hawaii Invasive Species
 Hawaii Invasive Species Video
Invasive Species
Questions:
How do you think rats harm the I’iwi bird
population?
Why do you think the rat population does so
well in Hawaii?