What is biodiversity?
Today we learned about possible definitions of
species. They include reproductive, viral host specificity, morphological,
location/habitat, genetic, and behavioral.
A. Reproductive – a naturally occurring interbreeding group
B. Viral host specificity – a unique group based on membrane surface proteins and markers
C. Morphological – a unique group based on shape
D. Location/habitat – a unique group that occupies a specific niche in a particular area
E. Genetic – a group with empirically distinguishable sequences
How do we measure it?
Simpson’s Biodiversity Index D = N(N – 1)/ ?[ni(ni-1)]
D represents the diversity index
N represents the total number of individuals in the sample
ni represents the proportion of individuals of a particular species
The higher the value of D, the greater the biodiversity
of the area.
The Biodiversity index depends on the species richness (number of species) and the eveness with which individuals are
distributed among species. There are several other equations to determine biodiversity indices.
What is the importance of biodiversity?
A. We rely on 3000
species to get through the day. Examples: food, clothing, and recycling
B. Food medicines
C. The value of biodiversity is twice the global domestic product
E. Economic resources
G. Chemical cycles
H. Propagation of species
I. Maintence of food chains
How does it impact us and how do we impact it?
A. Impact of biodiversity
B. Human impact on biodiversity
1. Humans drive biodiversity down
2. Domestication drives biodiversity down
3. Human habitats are inherently unstable
What are threats to biodiversity?
A. It is irreversible
B. Rate of extinction is 100-1000 times faster than the rate they were created
C. Mechanisms of extinction
1. Habitat loss
This includes deforestation to produce timber and create agricultural grazing areas and urban development.
Most deforestation of rainforests occurs in Indonesia and Costa Rica. When habitat loss occurs it not only
affects the lost area, but it also fragments the area around the lost area. Fragmentation encourages higher
predation rates because of the increased “edge” non-pure habitat. Also, less forested areas create increased
opportunities for parasitism.
2. Overexploitation (hunting, development)
3. Species introduction (non-native)
This is especially influential in disturbed habitats where it becomes easy for non-native species to take
over whereas in the wild they have a harder time
4. Predator control
D. What causes specific species to become extinct?
1. 80% habitat alteration
2. 75% introduced species
3. 40% chemical pollution (includes garbage, fertilizer and pesticide run-off)
4. 40% hybridization
5. 16% overfishing
Note: These percentages add up to more than 100% because species become extinct for more than one reason.
What are the solutions to slow down changes in biodiversity?
B. Governmental restrictions
1. Hunting/Fishing restrictions
2. Taxes on gas and electricity
3. Taxes on children to slow down overpopulation
C. Nature preserves and restoration
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