Science 10: 2.3 Bioaccumulation in Ecosystems Page 1 Science 10: 2.3 Effects of Bioaccumulation on Ecosystems Text: Chapter 2, pages 92-103 Part A: Synthetic Chemicals in the Ecosystem and Amphibians -Synthetic chemicals enter ecosystems by air, water and soil and are incorporated into the food chain when they are taken up by producers. are dangerous chemicals as they can affect the nervous, immune and reproductive systems of animals. -Amphibians are often good indicators of ecosystem health as they live on both water and land during their lifecycle. 1. Brainstorm why frogs are sensitive to synthetic chemicals in their environment. Water: Egg membranes are permeable; Breathe through skin = permeable skin. -For these reasons, amphibian species have declined significantly since the 1980s (other factors are also involved in this trend, such as deaths related to fungi). *Pesticides kill pests and can be classified as - Insecticides (kill insects) - Herbicides (kill weeds) Part B: How Pollutants Climb the Food Chain The introduction of synthetic chemicals has been one of the most damaging and presented the biggest challenge to clean up. Synthetic chemicals often cannot be broken down by decomposers and simply build up in the environment.
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Science 10: 2.3 Bioaccumulation in Ecosystems Page 1
Science 10: 2.3 Effects of Bioaccumulation on Ecosystems
Text: Chapter 2, pages 92-103
Part A: Synthetic Chemicals in the Ecosystem and
Amphibians
-Synthetic chemicals enter ecosystems by air, water and
soil and are incorporated into the food chain when they
are taken up by producers.
are dangerous chemicals as they can affect the
nervous, immune and reproductive systems of
animals.
-Amphibians are often good indicators of ecosystem
health as they live on both water and land during their
lifecycle.
1. Brainstorm why frogs are sensitive to synthetic
chemicals in their environment.
Water: Egg membranes are permeable; Breathe through
skin = permeable skin.
-For these reasons, amphibian species have declined
significantly since the 1980s (other factors are also
involved in this trend, such as deaths related to fungi).
*Pesticides kill pests and can be classified as
- Insecticides (kill insects)
- Herbicides (kill weeds)
Part B: How Pollutants Climb the Food Chain
The introduction of synthetic chemicals has been one of
the most damaging and presented the biggest challenge
to clean up.
Synthetic chemicals often cannot be broken
down by decomposers and simply build up in
the environment.
Science 10: 2.3 Bioaccumulation in Ecosystems Page 2
1. Bioaccumulation and Biomagnification
a) Bioaccumulation:
Accumulation of chemicals in organisms’
bodies.
How do synthetics enter an organism’s body and
how do they accumulate/are stored?
Enter through food, skin contact or
respiration.
Accumulate if taken up faster than broken
down.
Stored in fat tissue.
b) Biomagnification:
Accumulation of chemicals in increasing
concentrations in organisms’ bodies.
How are chemicals transferred from one trophic
level to the next?
Consumed with plant or animal tissue.
How does this scenario lead to an increase in the
concentration of synthetics in each successive
trophic level?
Consumers must eat many times their body
weight to survive
o small amounts of synthetics in
producers/prey being concentrated in
their bodies.
What are the implications for an ecosystem if a
Keystone Species (such as salmon) have significant
concentration of synthetics in their bodies?
Species rely on salmon for nutrients, either through predation, scavenging or decomposition.
Synthetics in their tissues would be transferred to a significant portion of the ecosystem.
Science 10: 2.3 Bioaccumulation in Ecosystems Page 3
1. PCB’s (and Killer Whales)
What are they?
PCBs (polychlorinated biphenyls) are synthetic chemicals