Energy in the Ecosystem FIELD BIOLOGY & METHODOLOGY Fall 2015 Althoff Lecture 05

_________________…defined again The __________________ of ecology…the biological and physical parts of nature together, unified by the dependence of animals & plants on their physical surroundings

Feeding Relationships Food ______--sequence of feeding relationships through which energy passes in ecosystem Food _____--various paths which energy passes in ecosystem

For simplicity…Food Chains: Have many links: plant, herbivore, carnivore Viewed as _____________, leading to a pyramid of energy (1940’s - Lindeman) Less and less energy passed on “___” the trophic levels

Pyramid of Energy (next slide) ____________________= reduced each trophic level (only 5-20%, on average, is transferred) Reduced efficiency corresponds to more and more assimilated energy spent on ______________

Food Chain Energetics ______________ = “self-nourishers”…make their own food from raw inorganic materials ______________ = “nourished by others”…obtain their energy and most nutrients from eating plants and/or other animals

Adding energy flow & nutrient cycling to the picture …Odum 1953 Important principle: energy passes from one link in the consumer food chain to the next, diminished by __________ and ______________.

Net production… one trophic level to the next E.P. Odum’s “universal” model of Ecological Energy Flow Ricklefs Fig. 22.2, p466

Odum’s contribution…con’t _______________ key component of “flow” Carbon, in particular, bears a close relationship to energy content because of its intimate association with photosynthesis

Primary Production (PP) _________ = capture of light energy = photosynthesis = primary producer status ___________= total energy assimilated by plants ___________= accumulated energy in plants & available to consumers

Global Patterns of NET Primary Production (NPP) Summarized in Ricklefs (p474, Fig ) (next slide) Terrestrial vs. Aquatic…what are the relationships & numbers saying?? A)_______________________ B)______________________ C)______________________

A B C

In Summary…. An ecosystem is the ______________ of organisms and the physical environment An ecosystem is a giant thermodynamic machine that dissipates energy continuously in the form of heat…..this energy initially enters the biological realm of the ecosystem via photosynthesis (by ____________), which provides energy for animals and nonphoto- synthetic microorganisms (_____________)

In Summary….con’t ____________ is the common currency for describing ecosystem function and structure Gross primary production is the total energy assimilated by photosynthesis. Net primary production is the energy accumulated in plant biomass Ecological efficiency (i.e., movement of energy) is _________ from one trophic level to the next Terrestrial ecosystems produce _____ NPP than aquatic ecosystems. Swamps & marshes #1