Transcript Limiting Factors and Populations

Biodiversity
Ch. 5 Notes
Definition: Biodiversity
Bio = life
Diversity = variety
 Variety
of species in an area
Benefits of Biodiversity
1.
Ecosystem stability

2.
Economic value


3.
Harvest / use
Use “best” individual or trait
Aesthetic value

4.
Replacements / alternatives
It’s “nice”
Scientific value
Genetic Diversity
 Variety
of genes and traits

A few will survive new / changing
conditions

Evolution: some traits will be “best” and
passed on
 Helps
with survival
Species Diversity
 Number
of different species, and their
abundance
 Fills
and replaces niches
 Greatest
at the equator,
decreasing toward the
poles
Ecosystem Diversity
 Variety
of ecosystems / biomes / habitats
 Different

conditions support different species
Allow for different tolerances
Threats to Biodiversity:
5.2 Extinction
2

Types:
1.) Background extinction
 Slow,
gradual
 More common in small habitats and islands

2.) Mass extinction
 Lots
of species in a short time
 Due to major disasters, continental drift,
climate change
Extinction

Occur occasionally
 444

mya , 360 mya, 251 mya, 200 mya, 65 mya
One may be occurring now
 Extinction
rate is 1,000 times greater than normal
Factors that Threaten Biodiversity
 1.)

Overexploitation
Too much use
 Usually

Value
Ex.) “The Lorax”
Continued…
 2.)
Habitat Loss:
 Destruction
 Cleared

for farms or houses
Disruption
 Organism
removed
 Food web interrupted / lost
Continued…
 3.)

Habitat Fragmentation
Broken into “islands”
 Creates
many edges that can be hard to live in
Continued…
 4.)
Pollution:
 Toxins
 Can
affect all organisms
 Often magnified as you move
up the food chain
Pollution Continued…
 Acid

rain
Dissolves nutrients out of soil
 Eutrophication

Fertilizers drain into water and help algae take over
Continued…
 5.)

Introduced Species:
Prey on, or out-compete,
many existing species
 Ex.)
Zebra mussels, kudzu
(U.S.)
 Almost ~40% of all
extinctions since 1750 have
come from introduced
species
Conserving Biodiversity: 5.3


Resources are helped by biodiversity
2 types:

Non-renewable resources
Very slow replacement / not replaced
 Ex.) Oil / coal, Metals / minerals


Renewables
Replaced very quickly
 Ex.) Solar, Wind, Water, Food


Sustainable use

Rate of use = rate of replacement
Protecting Biodiversity
 Protected

Parks, preserves, etc.
 Habitat

areas
corridors
Connect small
“islands” so animals
can safely migrate
Protecting Biodiversity
 Hot


spots (Pg. 132)
Special protections due to lots of biodiversity
Many endemic species found only there
 Laws

and treaties
CITES (No longer trading endangered organisms)
Restoring Biodiversity
 Bioremediation

Use living things to clean up pollution
 Bacteria,
fungi
 Ex.) Oil spills, mine contamination
 Bioaugmentation

Adding predators to limit one population
 Opens
up the habitat for other species
 Ex.) Ladybugs/ Aphids