THE BIODIVERSITY CRISIS
Species diversity is the variety of species in an ecosystem or throughout the biosphere.
The U.S. Endangered Species Act (ESA) defines an endangered species as: one that is “in danger of extinction throughout all or a significant portion of its range.”
Threatened species are those that are likely to become endangered in the foreseeable future.
Ecosystem diversity : Because of the network of community interactions among populations of different species within an ecosystem, the local extinction of one species, especially a keystone species, can have a negative impact on the overall species richness of the ecosystem.
38.2 Explain how human activities can threaten biodiversity.

Clearing rainforest for farming

Destruction of coral reefs
38.3
Describe the three greatest current threats to biodiversity, providing examples of each.
1. Habitat destruction : Human alteration of habitats poses the single greatest threat to biodiversity throughout the biosphere. The following have brought about massive destruction and fragmentation of habitats.
 agriculture
 urban development
 forestry
 mining
 environmental pollution
2. Invasive species : Disrupt communities by competing with, preying on, or parasitizing native species. ex. Snakehead fish in Florida
3 . Overexploitation : of wildlife by harvesting at rates that exceed the ability of populations to rebound.
 rare trees
 tigers
 whales

American bison

Galapagos tortoises
 numerous fishes
 primates for “bushmeat”
 rhinoceros horns
 elephant tusks
 grizzly bear gallbladders

N. Atlantic cod
‘Bison were hunted almost to extinction in the late 19th century primarily by market hunters and were reduced to a few hundred by the mid-1880s. They were hunted for their skins, with the rest of the animal left behind to decay on the ground.
After the animals rotted, their bones were collected and shipped back east in large quantities.’
Mrs. Loyd  Page 1 of 3 4/16/2020 cloyd@waukee.k12.ia.ushttp://loydbiology.weebly.comhttp://www.mybiology.com

38.4
Describe the process of biological magnification.
The concentration of toxins (chemical pesticides for agriculture) as they pass through the food chain. Top-level predators are usually the organisms most severely damaged by toxic compounds in the environment.
Example:
 PCB’s in the Great Lakes food chain fig. 38.4

Herring Gull eggs

5,000x higher than that measured in phytoplankton.

Concentration increased at each successive trophic level.
Example:

Mercury, a by-product of plastic production and coal-fired power generation

Routinely expelled into rivers and the sea

Bacteria in the bottom mud converted the waste to methyl mercury

Extremely toxic soluble compound that then accumulated in the tissues of organisms

Fish

Humans
CONSERVATION BIOLOGY AND
RESTORATION ECOLOGY
38.14
Describe the goals and methods of restoration ecology. Describe the goals and expected outcomes of the Kissimmee River Project.
Restoration Ecology
Goals:

To seek ecological ways to clean up degraded areas

To seek ecological ways to return degraded areas to their natural state
Methods:
 replanting vegetation
 fencing out non-native animal
 removing dams that restrict water flow

Bioremediation : the use of living organisms to detoxify polluted ecosystems. Emphasis is cleaning up toxins using bacteria and plants.
Mrs. Loyd  Page 2 of 3 4/16/2020 cloyd@waukee.k12.ia.ushttp://loydbiology.weebly.comhttp://www.mybiology.com

Kissimmee River Project:
Goals:

Restore the natural water flow patterns of the Kissimmee River and wetlands.
Expected outcomes:
Bring back:
 fish
 wetland bird populations
 spawning and
 foraging habitats for fishes
 sport fishes
 waterfowl
 bald eagle nesting territories
 filter and reduce agricultural runoff
38.15 Explain why sustainable development should be the ultimate goal for the long-term maintenance of human societies and the ecosystems that support them.
Sustainable Biosphere Initiative
Goals
 acquire the basic ecological information necessary for the intelligent and responsible development, management, and conservation of Earth’s resources.

Sustain the productivity of natural and artificial ecosystems
 study of the relationship between biological diversity, global climate change, and ecological process.
WHY?
To create a world in which each generation inherits an adequate supply of natural and economic resources and a relatively stable environment.
Mrs. Loyd  Page 3 of 3 4/16/2020 cloyd@waukee.k12.ia.ushttp://loydbiology.weebly.comhttp://www.mybiology.com