Science 10

Mr. JeanJune 6th, 2012

The plan:

• Video clip of the day• DDT• Bio-magnification• Sick swamp water? (maybe)• How many people can we fit on Earth?

Producers: Algae & water plants

Primary Consumer:• Coleps

• These were the very quick moving, very small oval shaped creatures.

Secondary Consumers:• Paramecium

• They would consume both the algae, water plants and the Coleps.

Top Carnivores• Spirostomum

• These worm like creatures eat the Paramecium.

• These were the largest microbes found in only a few Bio-worlds.

DDT:• Background of DDT

– DDT is a pesticide used for mosquito control and pest control in agricultural crops.

– DDT accumulation in some bird species resulted in death, nervous system damage, and reproductive failure.

– As a result DDT was banned in the United States in 1972.

What kind of damage can DDT cause to birds?

• In the body of an animal, DDT is changed (metabolized) to DDE.

DDE dissolves in fat, not in water, and is stored in fatty tissues. Thus, DDE tends to remain in the body and can cause several problems.

DDT: Kinds of Damage

• Reproductive failure (in birds- eggshell thinning)

• Immune system problems

• Nervous system damage

• Death

How does DDT move into lakes, streams and oceans?

•After DDT is applied, some DDT volatizes, some remains on the plant, and some washes off the plant into the soil, eventually making its way to a a stream, river, or lake.

•The DDT that remains on the leaves of plants may be ingested by primary consumers such as insects and rodents.

•DDT that has washed into a waterbody, remains in the sediment or is consumed by bottom-feeding organisms or absorbed by fish gills and skin.

Is DDT still used today?

YES

1. DDT is still used in some countries for insect control on crops.

2. In countries where mosquitoes carry malaria, DDT is currently used for mosquito control.

What is bio-magnification?

Osprey Food Web

Large Mouth Bass

Crayfish

Plant material and algae

3-76 µg/g ww

1-2 µg/g ww

0.2- 1.2 µg/g ww

0.04 µg/g ww

DDT Concentration

Osprey

Relationship Between DDE Concentrations and Eggshell Thickness

0.440.450.460.470.480.490.5

0.510.52

0 1 2 3 4 5 6

DDE Concentration

Eggs

hell

Thic

knes

s

low concentrations high concentration

normal

thin

Poisoning? What happened?

Results?

• Tertiary Consumers (top predator?):

Results?

• Secondary Consumers:

Results?

• Primary Consumers:

Results?

• Producers: