Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings “All flesh is grass” -Isaiah 40:6 ECOLOGY

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings “All flesh is grass” -Isaiah 40:6 Take a few minutes, think about the food web you created for HWF #1, and discuss with your partner if this phrase can be justified according to your food web.

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings “All flesh is grass” -Isaiah 40:6 Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist (1971)

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ecology Ernst Haeckel ( ) 1 st coined the word ecology in 1866 Derived from greek word, oikos meaning “house” Promoted and popularized Charles Darwin in Germany Recapitulation Theory – “Ontogeny recapitulates Phylogeny”

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Energy Flow and Geochemical Cycling in an Ecosystem

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Regardless of an ecosystem’s size, its dynamics involve two main processes: energy flow and chemical cycling Energy flows through ecosystems while matter cycles within them

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The first law of thermodynamics Conservation of Energy – States that energy cannot be created or destroyed, only transformed Energy enters an ecosystem as solar radiation, some is conserved, and much is lost from organisms as heat

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The second law of thermodynamics states that every exchange of energy increases the entropy of the universe In an ecosystem, energy conversions are not completely efficient, and much energy is lost as heat

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Conservation of Mass The law of conservation of mass states that matter cannot be created or destroyed Chemical elements are continually recycled within ecosystems Water cycle Nitrogen cycle Carbon/oxygen cycle Phosphorous cycle

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings In a forest ecosystem, most nutrients enter as dust or solutes in rain and are carried away in water Ecosystems are open systems, absorbing energy and mass and releasing heat and waste products

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Energy, Mass, and Trophic Levels Autotrophs build molecules themselves using photosynthesis or chemosynthesis as an energy source. Heterotrophs depend on the biosynthetic output of other organisms

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 6___ + 6____ → 6__ + _______

6CO 2 + 6H 2 O → 6O 2 + C 6 H 12 O 6

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Energy and nutrients pass from primary producers (autotrophs) to primary consumers (herbivores) to secondary consumers (carnivores) to tertiary consumers (carnivores that feed on other carnivores)

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Detritivores – organisms that feed on plant and remains and other dead matter examples: worms, crabs, sea stars decomposers, are consumers that derive their energy from detritus, nonliving organic matter Prokaryotes and fungi are important decomposers Decomposition connects all trophic levels

Fig. 55-3

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Global Energy Budget The amount of solar radiation reaching the Earth’s surface limits photosynthetic output of ecosystems Only a small fraction of solar energy actually strikes photosynthetic organisms, and even less is of a usable wavelength

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 55.2: Energy and other limiting factors control primary production in ecosystems Primary production in an ecosystem is the amount of light energy converted to chemical energy by autotrophs during a given time period

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Production Efficiency When a caterpillar feeds on a leaf, only about one-sixth of the leaf’s energy is used for secondary production An organism’s production efficiency is the fraction of energy stored in food that is not used for respiration

Fig Cellular respiration 100 J Growth (new biomass) Feces 200 J 33 J 67 J Plant material eaten by caterpillar *one-sixth of the leaf’s energy is used for secondary production *Energy transfer between trophic levels is typically only 10% efficient

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 55.3: Energy transfer between trophic levels is typically only 10% efficient Secondary production of an ecosystem is the amount of chemical energy in food converted to new biomass during a given period of time

Fig Primary producers 1,000,000 J of sunlight Primary consumers Secondary consumers Tertiary consumers Critical Thinking: You do the math - how much energy is available for each of the given trophic levels?

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Approximately 0.1% of chemical energy fixed by photosynthesis reaches a tertiary consumer A pyramid of net production represents the loss of energy with each transfer in a food chain

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings