Option G3 Impact of Humans on Ecosystems

Explain the cause and consequences of biomagnification, using a named example Causes- Toxic chemicals put into the environment and would not break down These chemicals were absorbed by microscopic organisms The chemicals, through consumption and other natural causes continued up the food chain increasing in concentration at each trophic level

Calculate the Simpson diversity index of two local communities Difference of species in an ecosystem Method: Find organisms. Identify organisms. Count individual species. Calculate. D= N(N-1)/ sum n(n-1) n= Total particular species. N= Total of all species.

What is the purpose of Simpson diversity? A.) To discover the amount and difference of species in an area. B.) To discover the richness of the ecosystem. C.) to discover the evenness in the ecosystem. Understand the habitat in that area.

Discuss reasons for the conservation of biodiversity using rainforests as an example. Conservation of biodiversity- Protection, management and restoration of wildlife. Lose 50,000 species a year in rainforests. Many destroyed by chainsaws, bulldozers, ect.. ;used for cattle or timber. Fruits, nuts, and natural medicines- also destroyed. Most biologically diverse. So diverse, less than one percent have been studied.

What is the importance of conserving biodiversity? A.) Save the many species that may be in danger. B.) Protect the life essential substances that may be destroyed. C.) Protect the species that are still to be discovered. D.) all of the above

List three examples of the introduction of alien species that have had significant impacts on ecosystems Floating fern, Salvinia molesta, damaged many lakes in the tropics and subtropics, grows rapidly doubling in number of leaves in about two weeks, and eliminates plant species Salvinia weevil (Cytrobagus salviniae) feeds on floating fern which can eliminate the damaging fern Black rats (Rattus rattus) reproduce very quickly and attack eggs and birds.

Discuss the impacts of alien species on ecosystems Interspecific competition- when one species overtakes an ecosystem potential damaging and destroying the community. Biological control- is a species that is introduced to control the interspecific competition. Species extinction- an alien specie can be introduced to the ecosystem and can force others to leave their habitat or kill them. Predation- Species introduced that prey on animals

Example of biological control Introducing the Salvinia weevil to feed off the floating fern so it would not spread and destroy the habitat.

Explain the cause and consequences of biomagnification, using a named example Consequences- First signs, decline in bird population Eggs of these birds cracked easily due to lack of calcium causing weak shells Shells broke when mothers tried sit on them Bald Eagles, Brown Pelican, Peregrine Falcon, Osprey, California Condors

Non-lethal skin cancer (ex. Basal and squamous cell carcinoma) Lethal skin cancer (ex. Malignant melanoma) Mutation of DNA (UV changes the structure of DNA) Sunburn (Reddening of skin caused by enlargement of blood vessels, some cells die and peel off) Cataracts (Clouding of the eye lens leading to a loss of vision) Reduced biological productivity (Causes complications making it hard for plants to photosynthesize) Outline the effects of ultraviolet (UV) radiation on living tissues and biological productivity

Outline the effects of chloroflurocarbons (CFCs) on the ozone layer Through a series of reactions the CFCs in the atmosphere are breaking down the ozone layer In the stratosphere CFCs break down chloride ions Chloride ions then react with ozone molecules to produce C1O and oxygen The C1O joins with an oxygen atom to form more oxygen gas and release another chloride ion This leaves a free chloride ion to destroy another ozone molecule, slowly depleting the ozone layer Ozone hole

State that ozone in the stratosphere absorbs UV radiation The ozone layer in the Earth’s stratosphere functions as a natural filter to helps disperse some of the harmful UV (ultraviolet) waves that are put of by the sun