higher in tropical terrestrial ecosystems as compared to equivalent temperate systems. 

-the accumulation of dead organic matter (litter) is highest in cold forests (especially Borest forests)

1. provides a mechanism for integrating information from many different ecosystems. organisms are assigned functional roles.
2. easier to compare ecosystems using the functional roles rather than taxonomic classifications.
1. for example we can compare nitrogen cycles in tropical versus temperate versus boreal ecosystems.
3.  ecosystems can be modeled more easily than populations or communities in many cases. 
4. the ecosystem approach has many applications:
1. resource management (fisheries, forestry) and pollution monitoring
2. global scale problems 

1. Ecological systems function according to the laws of thermodynamics (Ecosystems)
2. the physical environment exerts a controlling influence on the productivity of ecological systems (Ecosystems)

what is the principle source of energy?

Where does it arrive?

1. wave lengths
2. particles (photons)

the photons of different wavelengths have different energy values.

Describe long wave lengths and short wavelengths in terms of energy

long waves lengths: less energy

short wave lengths: more energy. 

• amount of heat energy needed to raise the temperature of 1g of wter 1 degrees celsius

rates: kcal/m^2/day

the accumulation of energy by heterotrophs

(herbivores, decomposers, etc) per unit area per unit time. 

• Terrestrial: 107.1 X 10^9 metric tons/year (65.9% of total)
• only a quarter of plant to work with
• Aquatic: 55.3 X 10^9 metric tons/year (34.1% of total)

describe the ecosystem with low production (NP):

(in terms of terrestrial and aquatic)

Terrestrial:

A) Deserts and

B) Tundras

  -These biomes make up almost 30% of the land     surface area of the world. 

Aquatic:

C) Open Oceans

   - which make up 90.9% of the total marine surface area. 

describe ecosystems with high production (NP):

[in terms of tropical wet forests)

Shallow aquatic areas including:

• marshes
• estuaries
• algal beds and
• coral reefs. 

1. temperature: tundra
2. moisture: dessert
3. light

• moisture avilability
• light
• temperature

1. moisture
2. light
3. temperature (as measured by Evapotranspiration)

warm water is less dense than cool water. 

-however, water reaches its maximum density at 4 degrees Celsius

describe Aquatic Ecosystem:

(Define the production of Thermal  Stratification)

In the Spring and fall, there are times when the lakes become isothermal. that is the temperatures are the same from top to bottom. 

-This encourages mixing of nutrients laden bottom water with oxygenated surface waters.

describe the lake productivity

(Oligotrophic)

(Mesotrophic)

• a lake with low productivity; usually a young lake with few nutrients, often deen with clear water. 
• a middle-aged lake with higher productivity and a higher nutrient level

define Eutrophic:

What is an example of it?

an old lake or a lake heavily affected by pollutants. Very high nutrient levels; productive, but very poor in species.

-Mason Lake

controlling the phosphorous input into a lake can cause nitrate pollution to increase

productivity is often measured as changes in standing crop over a unit of time. 

NPt-(t+1) :  NP in the time period (t) to (t+1)

H: losses due to herbivores

D: losses due to death and decomposition of plant parts

PE = NP/PAR

• marine systems: 25-50% (as high as 90%)
• terrestrial forests: 5-10%

1. litter production is linked to NP. More in the tropics, least in deserts
2. litter accumulation, however, is highest in high latitude Boreal forests because of slow decomposition rates
3. Litter is not uniform in composition.  The ratio of C/N determines the rate of decomposition.  The higher the ratio the slower the decomposition, because N is usually a rate limiting factor for decomposing organisms, just as it is for photosynthesis.  Fresh litter has a high C/N ratio and decomposes slowly
4. The higher the proportion of cellulose, woody fibers, lignin, and resins, the slower the decomposition
5. Very acidic or basic pHs also slow decomposition rates.  Acid pHs are common in bogs, for example, leading to an accumulation of peat.

shred, tear, and grind up the organic material, increasing its surface area and/or chemically processing the material in their guts

-this improves oxygen penetration of the organic material and opens up these tissues to ultimate decomposition by bacteria and fungi

• Energy flow from one trophic level to another is never 100% efficient
• efficiencies allow ecologists to measure rates of energy transfer and make comparisons among ecosystems as well as estimate the number of tropic levels that can be supported

Amont heterotrophs, assimilation efficiency is what?

And what does A and I stand for (in the equation)?

EA = A/I

A: amount of energy assimilated

I: amount of energy ingested. 

What is Growth (or) production efficiency?

And what does R & A stand for (in the equation)

WHAT is FINAL equation then?

EG = NP/A or

EG = 1 – R/A

R: respiration rate at this trophic level

A: amount of energy assimilated

NP = A - R

1. type of organism (heterotherm versus homeotherm) and
2. type of food consumed.

• Heterotherms: have higher growth efficiencies
• homeotherms: use large amounts of energy in respiration, thus have low growth efficiencies