2.3 Flashcards
(42 cards)
What are pesticides?
Chemicals used to eliminate pests, such as insecticides that kill insects and herbicides tags kill weeds.
What was introduced to the environment by humans that has caused huge changes?
Synthetic (man made) chemicals.
What is bioaccumulation?
The gradual build up of synthetic and organic chemicals in living organisms
What goes wrong in order for a chemical to accumulate?
If the chemicals are taken up faster than they are broken down and excreted.
How do chemicals enter organisms?
Through food intake, skin contact, or respiration.
Can chemicals be stored in the fat tissues of animals?
Yes
How do synthetic and organic chemicals effect animals?
They harm the nervous, immune and reproductive systems of animals.
What happens if synthetic and organic chemicals are bio accumulated?
They can cause birth defects and cause the animals to be unable to reproduce.
What are keystone species?
Species that greatly effect the population numbers and health of an ecosystem.
What is a keystone species in British Columbia?
SALMON
What is biomagnification?
The process in which chemicals not only accumulate, but become more concentrated at each trophic level
When do chemicals bioaccumulate and become biomagnified?
When they are stored in plant tissue and in the fat tissue of animals.
How are chemical freed of an animals body?
They have to be broken down for energy
What are PBCs?
They are polychlorinated biphenyls, which are synthetic chemicals that were widely used from the 1930s to the 1970s.
What were PBCs used for?
Heat exchange fluids, paints, plastics, and lubricants for electrical transformers.
What is a half life?
The amount of time it takes for a substance to decrease by half.
What effect do PBCs have on humans?
They suppress the immune system and cause cancer.
What animals was hit the hardest by PBCs?
ORCA WHALES
Why are PBCs so harmful to orca whales?
They are at the top of the food chain in the ocean, so they receive the highest concentration of chemicals like PBCs through bioaccumulation and biomagnification .
What class of compounds do PBCs belong to?
Persistent organic pollutants, or POPs.
What are POPs?
Carbon containing compounds that remain in water and soil for many years.
What is the ,easing way many POPs enter the ecosystem?
Insecticide sprays
What is a DDT?
A dichlorodiphenyl trichloroethane, which is an insecticide.
Where does DDT bioaccumulate?
In plants, the fatty tissue of animals that eat the plants, in streams, and lakes.