Ch. 11 – Biodiversity
Genetic Diversity: variation within a species
Species Diversity: different organisms within a community
Ecological Diversity: refers to the richness and complexity of a biological community.
About 1.7 million cataloged species
Estimated 3-50 million species in existence
About 65% are invertebrate life forms
Majority of threatened species are concentrated in the tropics (biodiversity hotspots)
Benefits to Biodiversity
Food Sources
Drugs & Medicines
Ecological cycles & processes
Aesthetic & cultural richness
Biodiversity is constantly changing…
Extinction: Elimination of a species
Naturally occurring process driven by evolution and natural catastrophes (~1 species per decade)
Can be accelerated by human disturbance
Threats to Biodiversity
H.I.P.P.O. (E.O. Wilson)
Habitat Destruction
(The single greatest human-caused reduction of biodiversity)
Invasive Species
Accidentally or intentionally
Pollution
Toxic pollutants
Population (of humans)
Diseases
Overharvesting
Poaching, illegal hunting & fishing, exotic pet trade
Biodiversity Management & Protection
Endangered Species Act
Endangered = in imminent danger of extinction
Threatened = likely to become endangered
Vulnerable = naturally rare or at risk due to humans
Species Recovery Plans
Habitat conservation, protection, and restoration
International Wildlife Treaties (C.I.T.E.S.)
Role of Zoos, Preserves, Game Parks, and Botanical Gardens
Zoologist Geroge Shaller argues for spending money out in the wild instead of on the walls
02/06 – Ecological Biodiversity: Preserving Landscapes
Primary Forests (Old Growth Forests)
Composed primarily of native species in which there is little indication of human activity and ecological processes are not significantly disturbed
Home to much of the world's biodiversity, ecological services, and indigenous cultures.
Less than ⅓ of the world’s forest
The U.S. has less than 10% remaining
Forest’s many uses (and abuses).
Construction material
Paper pulp
Fuel Wood (~50%)
Cropland (slash & burn)
¼ of the world's forests are managed for wood production, much of it replanted in single-species monoculture forestry.
Other threats include climate change, droughts, wildfires, and insect threats
Grasslands
Highly desirable for conversion to cropland due to rich soil composition
Often exploited by livestock overgrazing, which can lead to desertification
Process of Desertification
Elimination of most palatable grasses & herbs
Invasion by opportunistic weedy species
Pulverization by hooves, accelerating erosion
Protecting Ecosystem Diversity
U.S. National Park Service (1916)
Educate the public
Protect the environment
Preserve our natural heritage
Threats to our Park System
Governmental and business attacks for profit
Lack of funding
Overuse (loved to death)
What is the best Parks Management plan?
Core habitat – one of the reasons that large preserves are considered better than small reserves
Landscape Ecology
Science that examines relationships between spatial patterns and ecological processes such as species movement or survival
Variables
Habitat size
Shape
Relative amount of core and edge
Surrounding land composition
Specialist species
Can only survive in a narrow range of conditions
Have a limited diet
Have narrow niches
Are more prone to extinction
Examples include pandas and some plants that rely on specific amounts of rainfall
Generalist species
plants or animals that can live in many different environments and eat a variety of foods
well-adapted to a wide range of conditions, and can be found in many different regions of the world.
Phylogenetics is the study of how organisms are related to each other through evolution