Ch. 54.5 Pathogens and Ch. 55.1-3 energy flow

Zoonotic Pathogens

transferred to humans from other animals. Accounts for ¾ of the emerging human diseases. Can be direct or through an intermediate species called a vector. (ex: Avian flu= spread to humans as “Bird flu”)

vaccinating animals helps

1st law of thermodynamics

Energy can neither be created nor destroyed, but converted

2nd law of thermodynamics

every exchange of energy increases entropy

Primary producers

build organic molecules using sunlight or inorganic compounds

Heterotrophs

consumers that depend on production by primary producers

decomposers

are heterotrophs that get energy from detritus. When they die, they return inorganic molecules to soil

Gross primary production

is the total primary production. measured as the conversion of energy from light to the chemical energy of organic molecules per unit time. 

Net Primary Production

GPP minus energy used by autotrophs for respiration. Is usually about ½ of GPP

Net Ecosystem Production

Measure of the total biomass accumulation of producers and consumers during a given period. Is GPP minus the total respiration of all organisms

Primary Production in Aquatic Ecosystems

Is limited by light and nutrients. Nitrogen and Phosphorus are most common limiting nutrient

Primary production in Terrestrial Ecosystems

limited by temperature and moisture.

Adaptations to overcome limitations

Form mutualisms with nitrogen-fixing bacteria and mycorrhizal fungi

Root hairs to increase surface area

Secondary Production

amount of chemical energy a consumer gets from its food and converts to new biomass

Production efficiency

fraction of energy stored in food that is not used for respiration (insects have highest, humans have lowest)

Trophic efficiency

percentage of production transferred from one trophic level to the next. about 0.1% of chemical energy from photosynthesis reaches tertiary consumer