303 & 302 midterm review. a scientific method observation explanation test analyzecommunicate
TRANSCRIPT
303 & 302
Midterm Review
A Scientific Method
Observation
Explanation
Test
AnalyzeCommunicate
The Scientific Processes
Sarah was interested in studying the effects of lack of sunlight on the height of plants. She took two identical trays and filled them with the same type of soil and planted the same type of seed in each. She then decided that she would keep one tray in a room that was completely dark and the other on the window ledge. She watered each with 50 mL of water a day.
QUESTIONDoes light affect the growth of plants?Independent Variable
Amount of lightDependent Variable
Plant growthControl
Plant on window ledgeConstants
Amount of water, type of soil, type of seed, trays
Answers continued…Hypothesis
If a plant is placed in the dark, then it will not grow as tall as plant in normal sunlight.
Improvements?More plants
A Forest Food ChainGRASS
MOUSE
SNAKE
HAWK
1st Trophic Level
2nd trophic Level
3rd Trophic
level
4th Trophic
level
A Forest Food ChainGRASS
MOUSE
SNAKE
HAWK
Producer
1st Consum
er
2nd Consum
er
3rd Consum
er
1st Trophic Level
2nd trophic Level
3rd Trophic
level
4th Trophic
level
A Forest Food ChainGRASS
MOUSE
SNAKE
HAWK
Producer
1st Consum
er
2nd Consum
er
3rd Consum
erHerbivor
eCarnivor
eCarnivor
e1st
Trophic Level
2nd trophic Level
3rd Trophic
level
4th Trophic
levelWhat’s still missing?
What did the popcorn race demonstrate?
Why are food chains rarely more than 4 or 5 members (trophic levels) long?
Which law does this demonstrate?
The 10% Rule: 2nd Law of Thermodynamics in action
As you travel up the food chain, the amount of energy transferred to each organism declines – only 10% of the energy is passed on to the next
consumerthe remaining 90% is either:
1. Energy lost as heat,2.Energy/biomass is used growth as food3. Biomass excreted as waste
Actually 5-20%
Chemical Changes
http://www.npr.org/news/specials/climate/video/Video 3 – carbon and chemical change
Energy PyramidAside from ethics…why might
eating at a lower trophic level be a good idea?
Particle Size = Soil Texture SAND, SILT, CLAY
Soil Layers in ground
The Nitrogen CycleThe air is 78% nitrogen, why can’t organisms use this?
What role do bacteria play in the nitrogen cycle?
Pros & Cons
PersistenceWhy is it good? Why is it bad?How does it happen?
Carried by wind and water, remains in soilEasily dissolve in fat, stored
DDT
http://www.youtube.com/watch?v=LQ64sV0nSVU – DDT (2:55)http://www.youtube.com/watch?v=z7Lr1pCEcNU – chlordane persistent (1:44)http://www.youtube.com/watch?v=uf6KkjBCoVU – sprayed on children (0:31)http://www.youtube.com/watch?v=6Y-6hm7zpps – Rachel Carson (0:36)http://www.owlcorner.net/OwlCornerHome/BioAccumGame_files/Silent%20Spring.mov – spraying on people
dichlor-diphenyl-trichloro-ethane
Chlorinated hydrocarbon insecticide
Persistence and Biomagnification
Banned in 1972, but still found in 96% of samples
Used extensively in WWII
Thin eagle shells
Biomagnification/BioaccumulationConcentration of
pesticide increases as you move up the food chain
How does this relate to the Rule of 10%?
http://www.makingthemodernworld.org.uk/stories/the_age_of_ambivalence/02.ST.06/?scene=2
http://www.mcgrawhill.ca/school/applets/bcscience7/bioaccumulation/
IPM = Integrated Pest Managment
Biological PesticidesAnd
Changing Farming Practices
Pathogens - bacteria, protozoa, fungus
Chemicals from plants
Release predatory organisms
http://www.youtube.com/watch?v=vMG-LWyNcAs
Prevent Breeding / Birth Control
Plant companion crops
WISSAHICKON WATERSHED
SCHUYLKILL WATERSHED
DELAWARE WATERSHED
How would you define a point source and a nonpoint source?
What do you see?
ANIMATION
Gulf of Mexico Dead Zone
How are wetlands a proactive solution?
Earth = the natural filter
WATER CYCLE
WATER CYCLE
Fig. 13-6, p. 319
In the Primary, Secondary, Advanced columns, sort these concepts correctly
Optional, not usually done Settles large particles
Filters large particles which go to a landfill
Removes pollutants like nitrates and phosphates
Removes bacteria with chlorine or ultraviolet light
Adds O2 to promote bacterial growth
Uses a 2nd filter Bacteria added to decompose waste
What’s Left? Where’s it Go?WATER
Into a lake or river ocean
Crops/Golf coursePossible problems?
SLUDGELagoonIncineratorCrop fertilizerPossible problems?
Combined Sewer Overflow
Wastewater tx plants will always be in the basin of a watershed…why?