pesticide, bioaccumulation and biomagnification. brainstorm the pros and cons of pesticide on...
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Pesticide, Bioaccumulation and Biomagnification
Brainstorm the pros and cons of pesticide on whiteboard
Pesticides- Pros and Cons?Cons
1. Mutation randomly occur allows pest to develop resistance to pesticides
2. Costs lots of time and resources to constantly develop new poisons
3. They are often toxic substances and can accumulate and magnify in the food chain
Pros1. Protect, thus protecting industries’ and farmers’ profits
2. Prevent epidemic outbreak
What are pesticides?- are chemicals that kill pests- 2.3 million tonnes of pesticides used yearly
- 75% used in agriculture
Bioaccumulation
refers to an increase in the concentration of a chemical in an organism over time.
Bioaccumulation vs Biomagnification (of toxin e.g. pesticides)
Biomagnification (also bioamplification) is the increase concentration of toxic chemicals, such as pesticides as it is passed upwards and maximized to the top predator of the food chain
DDT- a dangerous pesticide
a DDT molecule
DDT:(stands for Dichlorodiphenyltrichloroethane)
- First produced in 1939-a highly potent, fat soluble insecticides
Case study 1: DDT and the bald eagle
Bald eagles feed on fishThey disappear for many reasons:- Loss of habitat (industrialization, deforestation)- Hunting- Toxins in lakein lake
DDT in the Great LakesHow DDT enter the Great Lakes?- In this food chain, what type of consumer is the bald eagle?- tertiary (top) consumer- How could DDT end up in the bald eagle with highest concentration?
Impacts of DDT on birds
double-crested cormorant
Egg shell thinning
DDT was banned in Canada in 1971
Discussion
There still countries haven’t banned DDT. Why would this be of concern to Canadians?
Breast milk contains fat. How breast-feeding might affect the concentration of DDT in a mother and in her baby?
Mercury Poisoning- Minamata diseasehttps://www.youtube.com/watch?v=oxB_SXbxY28
Choose the most correct statement(s)
a.The residents of Minamata have bioaccummulated mercury in their body
b.The residents of Minamata have biomagnified mercury in their body
c.The residents of Minamata display both bioaccummulation and biomagnification
d.The residents of Minamata have also suffered from lead poisoning
Mercury Poisoning- Minamata diseasehttps://www.youtube.com/watch?v=oxB_SXbxY28
Choose the most correct statement(s)
a.The residents of Minamata have bioaccummulated mercury in their body
b.The residents of Minamata have biomagnified mercury in their body
c.The residents of Minamata display both bioaccummulation and biomagnification
d.The residents of Minamata have also suffered from lead poisoning
You are what you eat
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