Presentation on theme: "Notes: Human Influences on Environment and Pollution (pg. 16-18) I. LOSS OF BIODIVERSITY –Biodiversity- is the variety of life in an area. This is a necessity."— Presentation transcript:
Notes: Human Influences on Environment and Pollution (pg. 16-18) I. LOSS OF BIODIVERSITY –Biodiversity- is the variety of life in an area. This is a necessity because organisms depend upon one another (food chain).
Threatened Species –Species population begins to decline rapidly –Example: African Elephants
Endangered Species: Number in population become so low that extinction is possible
Extinction –Disappearance of a species when the last member dies –Since early 1980 40 plant and animal species have become extinct
Causes of Extinction Overfishing: harvesting of fish or shellfish faster than the population can renew its numbers Example: Eastern oyster Overhunting: killing of organisms for food, fur, feathers or other body parts at a faster than the population can renew its numbers. Example: blue whale, tigers, snow leopards, elephants, rhinoceroses
Eastern Oyster Keystone species along NC estuaries Serve 3 major roles: food source, clean the water, provide habitat (build reefs) Overharvested, water pollution and habitat destruction led to 90% decline in population Result: increased pollution in estuaries and decline in other aquatic species.
African Elephants Population decline due to the poaching of elephants for their tusks which are made of ivory.
Threatened Endangered Extinct
II. What Humans Have Done to Affect Biodiversity Habitat Loss- Organisms lost homes and shelter because of human interaction
Deforestation Removal of all trees of a forest for either land development or wood supply. Not only results in habitat loss but also contributes to global warming as CO2 levels increase
Piedmont Urbanization As the population grows in the piedmont region of NC, there is a demand for more land development (homes, schools, roads, shopping centers) This leads to habitat destruction
Coastal Development Increased development to meet population increases Beach erosion leads to changes in natural habitats as well as alters beach ecosystems.
Habitat Fragmentation- Separation of wilderness from other wilderness area. –Construction of roads or buildings in nature
Habitat Degradation- Damage to habitat by POLLUTION. Example: acid rain or the depletion of the ozone layer.
Keystone Species: A species that plays a critical role in the community of an ecosystem Example: Eastern oyster
Introduction of invasive species An introduced species that is not native to that ecosystem Can wreak havoc due to having no natural predators or competition Example: –Kudzu –Rodents/insects traveling on cargo ships from other countries
Kudzu Imported from Asia in the 1800’s to help with soil erosion. Has outcompeted native plants and resulted in population decline of some small ground plants and can kill trees. Grows rapidly and few animals feed on it
Resource Destruction: Renewable resources- can regenerate if they are alive or can be replenished by biochemical cycles as quickly as they are used. Examples: soil, water, air, forests
Nonrenewable resources- cannot be replenished by natural processes as quickly as they are used. Examples: fossil fuels, minerals, metals Use of new technology requires certain minerals that can depleted rapidly as use is increased
Global Warming –The overall warming of our earth (a.k.a. the greenhouse effect) caused by increased levels of carbon dioxide that is released naturally by respiration and by the burning of fossil fuels. –See carbon cycle notes to review more causes of carbon dioxide release
Global Warming Increase in temperatures has lead to ice caps and glaciers melting: –increases sea level which can flood coastal towns –Results in habitat loss for polar bears
Global Warming Extreme weather changes have been contributed to increases in global temperature Example: Super storm Sandy
Destruction of the Ozone Layer –Caused by the use of chlorofluorocarbons (CFCs) (primarily found in aerosols and coolant systems) –Ozone layer is a natural sunscreen for our earth, it is diminishing and allowing more ultraviolet (UV) rays to pass through which has been correlated to increased cases of skin cancer.
Pesticide use- Rachel Carson wrote Silent Spring and made the public aware of the DDT pesticide problem
Pesticides are used to kill pests but can sometimes kill organisms that aren’t targeted. –Runoff can carry them into aquatic ecosystems.
Bioaccumulation: Pesticides (or pollutants) are passed through the food chain
Biomagnification: The highest amount of pesticides (or pollutants) are found at higher trophic levels due to the consumption of organisms with trace amounts of pesticides (or pollutants) at lower trophic levels.
Biomagnification: Major animal affected: Bald eagles and peregrine falcons decreased due to soft shells from exposure to DDT. This resulted in fewer chicks surviving and hatching and a population decrease.
Pollution: Pollutants that are released in one area often have an impact on a much larger area. The plume is the area that a substance touches (smoke stack in air or a pesticide in ground water)
Pollution: Release of harmful substances or energy into air, water or soil. –Burning fossil fuels releases carbon dioxide –Deforestation reduces numbers of plants that take in carbon dioxide –Ground water or runoff carrying pesticides from crops into water supply
Eutrophication: Excess nutrients are released into a body of water. Example: Waste lagoons on NC hog farms
Waste Lagoons Phosphorous and nitrogen compounds such as nitrates can seep into the soil Carried to aquatic ecosystems by groundwater or runoff Excess nutrients cause a population explosion of algae creating an algal bloom Algae thrives on nutrients and exceeds carrying capacity so they begin to die Decomposers become active on the algae which uses more oxygen Less oxygen available to other organisms which results in death of other organisms
Acid Rain Rain that has a pH lower than 5.6 –Caused when sulfur and nitrogen released from the burning of fossil fuels combine with water in the atmosphere –Harmful to plants and the animals that eat the plants