Chapter 55 – Conservation Biology

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Transcript Chapter 55 – Conservation Biology

Chapter 55 – Conservation
Goal oriented science seeking to
counter the biodiversity crisis.
I. Biodiversity Crisis
Rapid decrease in the Earth’s
variety of life.
A. Loss of Genetic Diversity
• Reduction in genetic diversity leads to
detriment of overall adaptive prospects
B. Loss of Species Diversity
Less types of species
Endangered vs. threatened
Local vs. global extinction
Loss of species = loss of genes
C. Loss of Ecosystem Diversity
• Each ecosystem has an effect on the
entire biosphere
D. 4 Major Threats to Biodiversity
1. Habitat Destruction
2. Introduced Species
3. Overexploitation
4. Disruption of Food Chains
* Examples of each?
II. Conservation at the
Population and Species Level
A. Small-Population Approach
1. Small populations are susceptible to
inbreeding and genetic drift
2. Extinction vortex
B. How Small is Too Small?
1. MVP – minimum viable population size / use
computers to determine
2. PVA – population viability analysis / use MVP
to predict population survival chances
3. Ne – effective population size / based on
breeding potential
- Ne = 4NfNm / Nf + Nm
- Use family size, maturation age, genetic
relatedness, gene flow, population size, etc.
- low Ne = inbreeding, bottlenecking, reduced
C. Declining Population Approach
1. Diagnosis
a. Confirm decline
b. Determine environmental
c. Determine possible cause /
d. Predictions for each hypothesis
e. Test most likely hypothesis
f. Apply results
III. Conservation at the
Community, Ecosystem, and
Landscape Level
A. Edges and Corridors
1. Edge – boundaries of ecosystems
- have their own communities
- sites of speciation
2. Movement Corridors – strips or clumps of
quality habitat connecting patches /
riparian areas
- promote dispersal and reduce
B. Preserving Ecosystems
1. Biodiversity Hot Spot
- small area with lots of endemic,
endangered, and threatened species
- make national parks here / too small
2. Zoned Reserves
- large area
- several undisturbed areas surrounded
by human changed areas
C. Restorative Ecology
• Is all damaged land “reclaimable”?
1. Bioremediation – use of biological
organisms to detoxify polluted
2. Biological Augmentation – use of
organisms to add essential materials to
degraded ecosystems
D. We NEED to Reassess
Our Priorities