Three components: Image

species diversity - within a community
genetic diversity - within a population or species
ecosystem diversity - variety of habitats

Species diversity - Image

species richness
relative abundance of species

How many species are described in the literature? About 1.5 million are known to science
How many are thought to exist on earth? Maybe 30 million. Estimates range from 10-100 million

Geographical patterns of species richness




Human activities affecting species - Fig 40.6

Reasons for preserving species

Agricultural importance -
   1. biocontrol agents
   2. soil microorganisms
   3. pollinators
   4. genes for plant breeding and genetic engineering
   5. new food crops
About 80% of people in LDC's rely primarily on traditional medicines, mostly from plants
   1. quinine

   2. taxol
   3. digitoxin from Digitalis

Soil stabilization
Because its the right thing to do

Characters of extinction-prone species

often K-selected species

low reproductive rate
feed at high trophic level
large size
very specialized feeding habits
limited distribution
prey on livestock
migratory species map plane
behavioral patterns

desirable to humans

Conserving species, communities and ecosystems

Genetic problems faced by small populations

loss of genetic diversity - little to fall back on in times of environmental change

increase in harmful homozygous recessives

Extinction vortex - Image

Captive propagation: The peregrine falcon (Falco peregrinus)

                  Northern Aplomado Falcon (Falco femoralis septentrionalis) program

                  Attwaters prairie chicken program

Sustaining genetic diversity: The black rhino Fig. 40.21

Preserving keystone species: flying foxes (a type of bat) Fig 40.22

Landscape Ecology

Restoration Ecology - Image and Fig. 40.20