1. Chapter 19-2 Ecology of Organisms

2. Objectives
Contrast abiotic factors with biotic factors, and list two examples of each
Explain the importance of tolerance curves
Describe adaptations that allow organisms to avoid unfavorable conditions
Explain the concept of the niche
Contrast the fundamental with the realized niche

3. Biotic & Abiotic Habitat: where an organism lives
Biotic: living components of the environment
Abiotic: Nonliving factors
How many of these can you name?
These are interdependent factors
The couple on the teeter tooter show that balance has to be maintained

4. Abiotic factors Temperature Humidity pH Salinity Oxygen Concentration
Sunlight
Nitrogen
Precipitation
Slope of terrain
Pressure

5. Response to a changing environment
There is a wide range of environments to survive in
Each organism adapts to a specific range
You can determine this range by measuring activity over different increment
Tolerance curve: graph of performance versus an environmental variable

6. Horsepower curve for an Engine
If you want to know the horsepower of an engine, you hook the engine up to a dynamometer. A dynamometer places a load on the engine and measures the amount of power that the engine can produce against the load. You can get an idea of how a dynamometer works in the following way. Imagine that you turn on a car engine, put it in neutral and press the accelerator pedal all the way down. The engine would run so fast it would explode. That's no good, so on a dynamometer you apply a load to the floored engine and measure the load the engine can handle at different engine speeds. Torque Imagine that you have a big socket wrench with a 2-foot-long handle on it and you apply 50 pounds of force to that 2-foot handle. What you are doing is applying a torque, or turning force, of 100 foot-pounds (50 pounds to a 2 foot long handle) to the bolt. You could get the same 100 foot-pounds of torque by applying one pound of force to the end of a 100-foot handle or 100 pounds of force to a one-foot-long handle. Similarly, if you attach a shaft to an engine, the engine can apply torque to the shaft. You can easily convert torque to horsepower by multiplying torque by rpm / So you might hook an engine to a dynamometer, floor it and use the dynamometer to apply enough of a load to the engine to keep it at, say, 7,000 rpm. You record how much load the engine can handle. Then you apply additional load to knock the engine speed down to 6,500 rpm and record the load there. Then you apply additional load to get it down to 6,000 rpm. And so on. What dynamometers actually measure is torque (in foot-pounds), and to convert torque to horsepower you simply multiply torque by (rpm / 5252). If you plot the horsepower versus the rpm values for the engine, what you end up with is a horsepower curve for the engine. A typical horsepower curve for a high-performance engine might look like this : What a graph like this points out is that any engine has a peak horsepower - an rpm value at which the power available from the engine is at its maximum. An engine also has a peak torque at a specific rpm. You will often see this expressed in brochures as " rpm and 290 ft-lb 5000 rpm". When someone says an engine has "lots of low-end torque" what they mean is that the peak torque occurs at a fairly low rpm value, like 2,000 or 3,000 rpm. Another thing you can see from a car's horsepower curve is the place where the engine has maximum power. When you are trying to accelerate fast, you want to try to keep the engine close to its maximum horsepower point on the curve. That is why you often shift to a lower gear to accelerate - by downshifting you increase engine rpm, which typically moves you closer to the peak horsepower point on the curve. If you want to "launch" your car from a traffic light, you would typically rev the engine to get the engine right at its peak horsepower rpm and then release the clutch to dump maximum power to the tires.
What a graph like this points out is that any engine has a peak horsepower - an rpm value at which the power available from the engine is at its maximum.

7. Acclimation Adjusting tolerance curve
If you spend a few weeks at a higher elevation your body begins to produce more red blood cells
EPO doping is artificially simulating this by injecting your own blood into you
“Blood doping”
Train high and play low?

8. Control internal conditions
Environments
Change!
Conformers change their
internal environment with the external
A lizard in the desert
Regulators use energy to control and maintain a constant internal environment
Some fish conform to temperature, but regulate salt concentration

9. Escape from Unsuitable Conditions
Dormancy: Hibernate or go into Torpor
Migration: Too cold? just walk south
Torpor: Short term hypothermia which bats & humming birds use to save energy
Hibernation: also called brumination is longer term hypothermia, both land and aquatic mammals do this, some sleep for the entire season some wake up about once a week
The monarch butterfly migration is amazing. Thousands of miles are covered by the lepidopteras, Each year it’s a new Generation and none of them have made the trip before, however the swarms of butterflys will stop at the same trees every year.

10. Niches Niche: an organisms position in the ecosystem
Has biotic & abiotic aspects
Resource acquisition, allocation, method of reproduction
Fundamental niche: everywhere it can potentially live
Realized niche: where it does live
Limited by competition

11. Niche Differences Generalists: Broad niches Specialists: Narrow niches
Cockroach
Humans
Specialists: Narrow niches
Koala
Humming bird
Koalas are the laziest animals on earth sleeping for up to 21 hours a day. Their entire lives are dependent on Eucalyptus. Its their food and shelter and they can’t live anywhere else. What does this have to do with the theory of interconnectedness?

12. There’s only one earth