1 Energy Sources Organisms can be classified by trophic levels. – Autotrophs use… ______________: Use CO 2 as carbon source, and sunlight as energy. ______________: Use inorganic molecules as source of carbon and energy. – Heterotrophs use… BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

2 Solar - Powered Biosphere Light propagates through space… – _________: Particle of light bears energy. ____________ (IR) Long-wavelength, low energy. – ____________(UV) Short wavelength, high energy. – – _____________________________________(PAR) BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

3 Photosynthetically Active Radiation BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

4 Solar - Powered Biosphere PAR – Quantified as _____________________. Number of photons striking square meter surface each second. Chlorophyll absorbs light as photons. Landscapes, water, and organisms can all change the amount and quality of light reaching an area. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

5 Photosynthetic Pathways – Used by… – CO 2 + ribulose bisphosphate (5 carbon sugar) = phosphoglyceric acid (3 carbon acid) BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

6 C 3 Photosynthesis BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

7 Photosynthetic Pathways – Reduce internal CO 2 concentrations. – Acids produced during carbon fixation diffuse to specialized cells surrounding _______________. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

8 C 4 Photosynthesis BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

9 Photosynthetic Pathways – (Crassulacean Acid Metabolism) – Limited to succulent plants in arid and semi-arid environments. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

10 CAM Photosynthesis BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

11 Using Organic Molecules Three Feeding Methods of Heterotrophs: – _______________: Feed on plants. – _______________: Feed on animal flesh. – _______________: Feed on non-living organic matter. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

12 Chemical Composition and Nutrient Requirements Five elements make up 93-97% of biomass of plants, animals, fungi and bacteria: – – – – – BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

13 Essential Plant Nutrients Potassium Calcium Magnesium Sulfur Chlorine Iron Manganese Boron Zinc Copper Molybdenum BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

14 Herbivores Substantial nutritional chemistry problems. – Low... Must overcome plant physical and chemical defenses. – Physical – Chemical BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

15 Detritivores Consume food rich in ___________________, but poor in ______________. – Fresh detritus may still have considerable ________________________ present. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

16 Carnivores Consume … – Cannot choose prey at will. Prey Defenses: – – – BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

17 Carnivores Predators are usually selection agents for refined prey defense. – Usually eliminate more conspicuous members of a population (less adaptive). – Must catch and subdue prey - ________________. Predator and prey species are engaged in a co- evolutionary race. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

18 Using Inorganic Molecules Organisms found living on sea floor. – Near nutrients discharged from volcanic activity through oceanic rift. Autotrophs depend on chemosynthetic bacteria. – – BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

19 Energy Limitation Limits on potential rate of energy intake by animals have been demonstrated by studying relationship between feeding rate and food availability. Limits on potential rate of energy intake by plants have been demonstrated by studying response of photosynthetic rate to photon flux density. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

20 Photon Flux and Photosynthetic Response Curves Rate of photosynthesis increases linearly with photon flux density at …, rises more slowly with __________________, and tends to level off at _________________. – Response curves for different species generally level off at _______________ maximum photosynthesis rates. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

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22 Food Density and Animal Functional Response Holling described (3) basic functional responses: – 1. Feeding rate increases linearly as food density increases - levels off at maximum. – 2. Feeding rate rises in proportion to food density. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

23 Food Density and Animal Functional Response 3. Feeding rate increases most rapidly at intermediate densities – BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

24 Optimal Foraging Theory Assures if energy supplies are limited, organisms cannot simultaneously maximize all life functions. – Must compromise between competing demands for resources. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

25 Optimal Foraging in Bluegill Sunfish BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

26 Optimal Foraging Theory All other things being equal,more abundant prey yields larger energy return. Must consider energy expended during: Tend to maximize rate of energy intake. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

27 Optimal Foraging By Plants Limited supplies of energy for allocation to … Bloom suggested plants adjust allocation in such a manner that all resources are equally limited. – Appear to allocate growth in a manner that increases rate of acquisition of resources in ______________________. BIOL 3240 Plant and Animal Ecology – Energy & Nutrients

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