Opening Questions
-
Upload
margaret-greene -
Category
Documents
-
view
17 -
download
1
description
Transcript of Opening Questions
![Page 1: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/1.jpg)
Opening Questions
• Name two kinds of bias.
• Name three sources of bias.
• What are some important aspects of DDT?
![Page 2: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/2.jpg)
Lesson 1 Review Points
• Using Science as Evidence– When science is used as evidence it is important to
identify possible sources of bias.– Bias may be due to sampling bias or measurement
bias.
• 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.
![Page 3: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/3.jpg)
What are some sources of bias?
• Applying the results of a study too broadly (generalizing)
• Taking research results out of context
• Not taking a random sample
• Taking too small of a sample
• Measurement error
![Page 4: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/4.jpg)
Lesson 2
Food Webs, Bioaccumulation, and
Visualizing Data
![Page 5: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/5.jpg)
What kind of damage can DDT cause to birds?
![Page 6: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/6.jpg)
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.
![Page 7: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/7.jpg)
DDE: Kinds of Damage
• Reproductive failure (in birds- eggshell thinning)
• Immune system problems
• Nervous system damage
• Death
![Page 8: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/8.jpg)
How does DDT move into lakes, streams and oceans?
![Page 9: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/9.jpg)
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.
![Page 10: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/10.jpg)
Is DDT still used today?
![Page 11: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/11.jpg)
YES
DDT is still used in some countries for insect control on crops.
In countries where mosquitoes carry malaria, DDT is currently used for
mosquito control.
![Page 12: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/12.jpg)
What is a Food Web?
![Page 13: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/13.jpg)
Food Web = A summary of the feeding relationships within an ecological
community.
ORGANIC DEBRIS
Osprey
Water Plants
Sucker
Bay Shrimp
Trout
Plankton
Silverside
![Page 14: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/14.jpg)
Food Chain = One thread of the food web
ORGANIC DEBRIS
Osprey
Large Mouth Bass
Crayfish
![Page 15: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/15.jpg)
Cast of Food Web Characters
• Tertiary Consumers – Animals that eat animals that eat animals
• Secondary Consumers – Animals that eat animals that eat plants
• Primary Consumers – Animals that eat plants
• Primary Producers – Plants and Phytoplankton: organisms using the sun for energy
![Page 16: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/16.jpg)
Why is food web knowledge important for understanding the impact of DDT on ospreys and
eagles?
![Page 17: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/17.jpg)
Ospreys and eagles are tertiary consumers and this makes them particularly vulnerable
to DDT because of
bioaccumulation and biomagnification.
![Page 18: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/18.jpg)
What is bioaccumulation?
![Page 19: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/19.jpg)
Bioaccumulation = the accumulation of a contaminant or toxin in or on an organism
from all sources (e.g., food, water, air).
An increase in the concentration of a chemical in a biological organism over time, compared to the chemical's
concentration in the environment. Compounds accumulate in living things any time they are taken up and stored faster
than they are broken down (metabolized) or excreted.
![Page 20: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/20.jpg)
What is biomagnification?
![Page 21: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/21.jpg)
Biomagnification = the increase in concentration of toxin as it passes through
successive levels of the food web
DDE accumulates at higher levels in organisms that are higher in the food chain
![Page 22: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/22.jpg)
Biomagnification of a DDE in Aquatic Environment
Tertiary Consumer 3-76 µg/g ww
(fish eating birds)
Level Amount of DDE in Tissue
Secondary Consumers 1-2 µg/g ww
(large fish)
Primary Consumers
(small fish)0.2-1.2 µg/g ww
Primary Producers
(algae and aquatic plants)
0.04 µg/g ww
![Page 23: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/23.jpg)
Considering biomagnification, how could DDE harm an
osprey?
![Page 24: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/24.jpg)
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
DDE Concentration
Osprey
![Page 25: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/25.jpg)
Units of Measurement
1 gram = 1000 milligrams (mg) = 1,000,000 micrograms (µg)
microgram (µg) = one millionth of a gram
To describe concentrations: µg/g = number of micrograms (of toxin) per gram (of tissue)
2 µg/g DDE in egg content means there is 2 parts of DDE in 1,000,000 parts of an egg contents
ww or wet weight refers to the fresh weight of animal tissue.
dw or dry weight refers to the weight of animal tissue after it has been dried in an 65°C oven to remove all the water.
![Page 26: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/26.jpg)
The Effects of DDE on Reproduction
Species Effect on Reproduction
DDE: Critical Concentration (measured in egg contents)
Bald Eagle None < 3µg/g 1
Bald Eagle Failure 16 µg/g 1
Osprey Failure 17.6 µg/g 2
1. Wiemeyer, S.N. et al., 1984. Organochlorine pesticide, polychlorobiphenyl, and mercury residues in bald eagles, 1969-1979, and their relationship to shell thinning and reproduction. Arch. Environ. Contam. Toxicol., 13, 529.
2. Johnson, D.R. et al., 1975. DDT and PCB levels in Lake Coeur d’Alene, Idaho osprey eggs, Bull. Environ. Contam. Toxicol., 13, 401.
![Page 27: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/27.jpg)
High levels of DDE cause the female ospreys to lay eggs with thin eggshells.
Thin eggshells have a greater chance of breaking, leading to embryo death.
With high levels of DDE, female ospreys can also lay eggs that contain high enough
concentration of DDE to prevent embryo development.
![Page 28: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/28.jpg)
How is the impact of DDE on osprey and eagle reproduction
measured?
![Page 29: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/29.jpg)
One Method for Measuring the Impact of DDE on Osprey Reproduction
• Collect eggs from abandoned osprey nests.
• Measure the thickness of the eggshells.
• Measure the amount of DDE in the egg.
• Determine the association between eggshell thickness and DDE residue.
![Page 30: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/30.jpg)
Visualizing the Data
![Page 31: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/31.jpg)
If increased DDE concentrations causes increased eggshell thinning, how would
you draw a graph showing the relationship between eggshell thinning
and DDE concentration?
![Page 32: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/32.jpg)
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
Eg
gsh
ell
Th
ickn
ess
low concentrations high concentration
normal
thin
![Page 33: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/33.jpg)
If DDE has no impact on eggshell thickness, what relationship would you expect to see between DDE levels and
eggshell thickness?
![Page 34: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/34.jpg)
Relationship Between DDE Concentrations and Eggshell Thickness
0
0.1
0.2
0.3
0.4
0.5
0.6
0 2 4 6 8 10 12
DDE Concentration
Eg
gsh
ell
Th
ickn
ess
high concentrationlow concentration
normal
thin
![Page 35: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/35.jpg)
If increased levels of DDE are associated with increased eggshell
thickness, how would you make a graph showing the relationship between
eggshell thickness and DDE concentration?
![Page 36: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/36.jpg)
Relationship Between DDE Concentrations and Eggshell Thickness
0.4
0.45
0.5
0.55
0.6
0.65
0 1 2 3 4 5 6 7 8
DDE Concentration
Eg
gsh
ell
Th
ickn
ess
high concentrationlow concentration
normal
thin
![Page 37: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/37.jpg)
DDE reduces reproductive rates at moderate concentrations. At high
concentrations it causes total reproductive failure.
How would you make a graph showing the relationship between
DDE concentration and reproductive success?
![Page 38: Opening Questions](https://reader030.fdocuments.in/reader030/viewer/2022032605/56812bd6550346895d90405b/html5/thumbnails/38.jpg)
Relationship Between DDE Concentrations and Eggshell Thickness
0
20
40
60
80
100
0 2 4 6 8 10 12
DDE Concentration
Rep
rod
uct
ive
Su
cces
s
high concentrationlow concentration
high
low