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pesticides and bioaccumulation.notebook December 06, 2015

Unit 1

• Review

• Pests

• Pesticides

• DDT

• Bioamplification

• conclusion

• Challenge!

Life Science: Sustaining Ecosystems


Algae Blooms

• The nitrogen cycles can be changed by the actions of humans.

• Fertilizing farms results in runoff from rain being rich in phosphorous and Nitrogen.

• This water ends up in ponds and causes algae to grow.


• When the algae die, bacteria break it down and grow faster than usual.

• This can happen natural, but humans make it happen faster

Also known at Eutrophication

Algae Blooms


http://www.youtube.com/watch?v=UGqZsSuG7ao

http://www.youtube.com/watch?v=UGqZsSuG7ao


Pesticides p.3437

• Pest – An organism that humans do not like.

• What a pest is depends on who you ask.

Which ones are pests?


Pesticides p.3437

• If you are trying to grow carrots, a dandelion or even a cabbage are pests.

• Pests can include: plants, fungi, insects or mammals.

• Pesticide – A chemical that kills pests.

• Pesticides usually kill only one type of organism.E.g. insecticide kill insects.


Pesticides• About 30% of the crops in Canada are destroyed by pests.

• Pesticides help us make more food and to prevent diseases like malaria.

• Malaria is a disease that damages blood and is spread by mosquitoes.

• Pesticides can kill the mosquitoes before they spread the disease.


Pesticides

• Although some pesticides affect only a few species, others affect many different kinds.

• If these types of pesticides are used they can affect many parts of the ecosystem.

• This can be a serious problem if large areas of land are sprayed with pesticides, as is often done to kill insects.


• E.g. DDT

• DDT was an insecticide used in Canada and the U.S. in the 1950s 1970s.

It was a good insecticide because it was cheap and killed a lot of insects.

Pesticides


Pesticides DDT

• However people noticed that there were few birds in areas where DDT was used.

• Eventually they found out that the birds had high levels of DDT in their system.

• In birds DDT cause their eggs to have thin shells.

• Eggs with thin shells easily break, killing the baby birds.


How did DDT get into the birds?

Question:


Pesticides• Bioaccumulation – As you go up food chains, there is more and more poison in the organisms.

• Insects have only a little poison in them.

• But they are eaten by mice.

• The mice then get more poison in them.

• Then birds eat the mice and get even more poison them.


• There is an outbreak in Terrenceville of an insect that eats blueberries.• State a benefit and problem with doing each of the following:

1. Use an insecticide to kill the insect.2. Bring in another insect to eat the pest3. Do nothing

Which do you think is best?

Attachments

1206Attendance.xlsx

Sheet1

5-Sep

Gustav Barbourp

Echo Henochp

Toni Lampep

Anthony Saksagiakp

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Kayla Wyattp

Sheet2

Sheet3

SMART Notebook

Page 1: Sep 8-9:31 AMPage 2: Nov 3-2:26 PMPage 3: Dec 2-7:40 AMPage 4: Dec 2-7:32 AMPage 5: Jan 29-5:33 PMPage 6: Jan 29-5:34 PMPage 7: Jan 29-5:35 PMPage 8: Jan 29-5:38 PMPage 9: Jan 29-5:41 PMPage 10: Jan 29-5:40 PMPage 11: Jan 29-5:43 PMPage 12: Jan 29-5:44 PMPage 13: Jan 29-5:47 PMPage 14: Sep 8-9:31 AMAttachments Page 1

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