Transcript Biological Diversity

Biological Diversity
Objectives:
1. Define biodiversity and distinguish
between species richness, genetic
diversity, and ecological diversity.
2. Describe several important ecosystem
services provided by biodiversity.
Biological Diversity
Biodiversity
Species Richness - # of species
Genetic Diversity- variation within a
population of species
Ecosystem Diversity- variety of
interactions among organisms in
communities
Biological Diversity
Genetic Diversity in Corn
Biological Diversity
Why We Need Organisms
• Ecosystem Services and Species Richness
Nests
eventually
become small
islands of trees
Gator trails clear
out aquatic
vegetation
Maintains
smaller fish
populations by
eating gar
Digs underwater
holes used by
other aquatic
organisms
Biological Diversity – GOOD STUFF!
• Ecosystem Services
– Forests maintain freshwater supplies, reduce floods,
and prevent erosion
– Plants depend on insects for pollination
– Soil fertility
– control pests and disease-carrying organisms
– Decomposers recycle nutrients in ecosystems
• Genetic variablilty is important to the long-term
health of a species
• Genetic diversity is utilized in genetic
engineering applications
• Organisms are used for medicines, agriculture,
and industrial products
• Aesthetic, Ethical value or organisms
Biodiversity and Human Health
• Organisms have a role in maintaining clean fresh
water supplies
• Biodiversity keeps populations of disease
carrying organisms from increasing
• Organisms are sources of medicines and foods.
• Organisms serve as medical models that help
scientists understand physiology and disease.
• Certain organisms sensitive to environmental
pressures can warn of potential threats to human
health.
Endangered and Extinct Species
Extinction – elimination of a species from
Earth (irreversible?)
Background extinction – a continuous lowlevel rate of extinction that has occurred
throughout Earth’s history
Mass extinction – numerous species become
extinct over a geologically short period of
time.
Endangered and Extinct Species
Background Extinction vs. Mass Extinction
Continuous, slow
rate of extinction
over millions of
years
Numerous
species disappear
over geologically
short time frame.
Endangered and Extinct Species
Endangered and Threatened Species
Could become
extinct soon.
Population
declining very
fast.
5 Mass Extinction Events
5 Mass Extinction Events
Ordovician – 440 million
years ago
•Massive glaciation – water
locked up in the form of
ice/drastic decline in sea
level
Cause: Climate Change
•Many marine organisms
disappeared (85%)
5 Mass Extinction Events
Late Devonian –
•359 million years ago
•75 % of all species
disappeared
Possible causes: asteroid, comet, or meteor
impact  climate change
5 Mass Extinction Events
Permian
•250 million years ago
•95 % of all species
disappeared
•Largest extinction
event
Possible causes:
•Impact event (asteroid)
•Catastrophic methane release
•Flood basalt eruptions
•Drop in oxygen levels
•Sea level fluctuation
5 Mass Extinction Events
Triassic-Jurassic
•200 million years ago
•50 % of species
disappeared
•Mainly effected animals
rather than plants
Possible causes:
•Climate change
•Flood basalt eruptions
•Impact event
5 Mass Extinction Events
Cretaceous-tertiary
•65 million years ago
•Famed for the extinction
of dinosaurs
•Many other species also
disappeared.
Possible causes:
•Flood basalt eruptions causing climate change,
subsequent sea level decline, followed by an
asteroid or comet impact
th
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Are we in the middle of a
mass extinction event?
And will it include humans?
• Scientists estimate that the rate of
extinction is currently 100 to 1000 times
larger than the background extinction rate.
Endangered and Extinct Species
American Bald Eagle
•In 1963, there
were only 417
nesting pairs in
the lower 48 US
states
•7500 nesting
pairs in 2004
•Now listed as
threatened
species
Endangered and Extinct Species
1.
2.
3.
4.
Factors Leading to the Decline of Bald Eagles
Loss of habitat
Many were hunted for sport and to save
commercial fishing
Slow rate of reproduction
DDT – contaminated food caused shells to be
too thin for embryos to survive
Endangered and Extinct Species
Factors contributing to the recovery of Bald Eagles
1. DDT was banned in the US in 1972
2. Bald Eagles were listed as an endangered
species when the Endangered Species Act was
passed in 1973
3. Bald Eagles were bred in captivity
4. Eggs were removed from nest in nature and
baby eagles were raised in wildlife refuges and
returned to nature
5. Removal of eggs helped because eagles lay
additional eggs to replace ones that were
removed.
Which is more likely to become
endangered?
The tiburon mariposa
lily is only found on a
single mountaintop in
northern California
The common chicory is
found on roadsides in
Europe, North America,
and Australia
Which is more likely to become
endangered?
The california ground
squirrel is a primary
consumer that rarely
travels more than 50 m
from it’s burrow.
The california condor is
a tertiary consumer that
requires hundres of
square kilometers to
find an adequate supply
of food.
Which is more likely to become
endangered?
The American robin is
found in all parts of
North America
The Hawaii O’o is a bird
found only in Hawaii.
Which Species is More Likely to
Become Endangered?
The blue whale
produces a single calf
every other year..
The cane toad lays 8,000
to 25,000 eggs at a time.
Which species is more likely to
become endangered?
The pacific salmon is a
saltwater species that
migrates to freshwater
to spawn once and die.
The brown trout is a
freshwater species that
do not migrate to spawn
and spawn numerous
times throughout their
lives.
Endangered and Extinct Species
Characteristics of Endangered Species
• Extremely small range Tiburon mariposa lily
• Requiring large territories California condor
• Living on islands Hawaii ‘O’ o
• Low reproductive success Blue whale
• Specialized breeding areas Green sea turtle
• Specialized feeding habits Giant panda