Marika DeliyianniAP Biology2nd period

Terrestrial and Wetland Ecosystems: Primary Production

• Temperature and moisture control primary production in ecosystems.

• Actual evaporation is the measure of annual amount of water transpired.

• The higher the actual evaporation in an ecosystem the more net primary production.

• Primary production can remove soil nutrients and lack of mineral nutrients can limit primary production(that’s why farmers use fertilizer, so as to add nutrients that may go missing).

In terrestrial and wetland ecosystems phosphorus and nitrogen are usually limiting the production

Energy Transfer

• Secondary Production is the amount of chemical energy that is changed into biomass

-When you eat a carrot most the energy is used to dispel feces, some for respiration, and the smallest amount is used for growth/reproduction(new biomass)

• Net Secondary Production is stored energy in biomass• Assimilation of Primary Products is total energy used for

growth/reproduction/respiration • Production efficiency = (Net SP) / (Assimilation of PP)• Endothermic creatures have typically low efficiency since they need to

use energy to regulate their body temp.

• Trophic efficiency is percentage of production transmitted from on trophic level to next.

• Trophic efficiencies are ALWAYS less than production efficiencies.

• As energy moves up the levels the amount passed along gets smaller since a large part is used.

Pyramids!• Pyramid of Production: this

represents the loss of energy with transfers between trophic levels.

Pyramid of Biomass(standing crop): represents total dry weight of each tier.Turnover time = (total crop bioass) / (production)Some aquatic ecosystems can have the pyramid upside down.

• Pyramid of Numbers: limited biomass for the top of pyramids tend to concentrate in a small amount of large individuals.

• You gain more energy by eating a certain amount of grains directly ( as primary producer) than by eating the same amount through eating a piece of meat that of a grain fed animal.

Green World Hypothesis• A variety of factors exist that limit terrestrial herbivores to

consume comparatively little plant biomass and allow terrestrial ecosystems to have large amounts of vegetative standing crops.

Plants have defenses like poisons, spines, and noxious chemicals Nutrients limit herbivores since growth and reproduction

depends on these nutrients Abiotic factors, like temperature changes or moisture Intraspecific competition like territorial behavior limit herbivore

numbers Interspecific interactions limits herbivore density