Biomagnification

Biodiversity The total sum of species in an area This is a natural resource and needs protection

Why ? We get medicines, food and Diversity

Threats to biodiversity... Human activity alters habitats Extinction, endangered species Invasive Species: new species that are introduced to an area that reproduces rapidly causing ecological change.

Biomagnification Organisms at the top of the food chain have a higher degree of harmful substances then the organisms at the lower levels.

How does this occur? Farmers use a pesticide on crops It does not biodegrade, so it washes into the streams Algae absorbs it; small fish eat the algae The bigger fish eat lots of small fish (therefore lots of pesticide) Large birds eat the fish The highest concentration of pesticides are found at this level.

Example: Bald eagles and their eggs Rachel Carson discovered this Must know figure 6-16 in book