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Energy and Nutrient Relations

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Title: Energy and Nutrient Relations


1
Energy and Nutrient Relations
  • Chapter 6

2
Energy Sources
  • Organisms can be classified by trophic levels.
  • Autotrophs use inorganic sources of carbon and
    energy.
  • Photosynthetic Use CO2 as carbon source, and
    sunlight as energy.
  • Chemosynthetic Use inorganic molecules as source
    of carbon and energy.
  • Heterotrophs use organic molecules as sources of
    carbon and energy.

3
Solar - Powered Biosphere
  • Light propagates through space as a wave.
  • Photon Particle of light bears energy.
  • Infrared (IR) Long-wavelength, low energy.
  • Interacts with matter, increasing motion.
  • Ultraviolet (UV) Short wavelength, high energy.
  • Can destroy biological machinery.
  • Photosynthetically Active Radiation (PAR)
  • Between two extremes.

4
Photosynthetically Active Radiation
5
Solar - Powered Biosphere
  • PAR
  • Quantified as photon flux density.
  • 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.

6
Light Spectrum and absorption
  • plant pigments, chlorophyll a, b, carotenes,.
    xanthophyll, leutin, anthocyanin

7
What are the 3 types of photosynthesis, how do
they vary, give examples of each.
  • C3 most plants ie. sunflowers
  • C4 grasses most prairie grasses, big blue
    stem
  • CAM desert succulents

8
Photosynthetic Pathways
  • C3 Photosynthesis
  • Used by most plants and algae.
  • CO2 ribulose bisphosphate (5 carbon sugar)
    phosphoglyceric acid (3 carbon acid)
  • To fix carbon, plants must open stomata to let in
    CO2 .
  • Water gradient may allow water to escape.

9
C3 Photosynthesis
10
Photosynthetic Pathways
  • C4 Photosynthesis
  • Reduce internal CO2 concentrations.
  • Increases rate of CO2 diffusion inward.
  • Need fewer stomata open.
  • Conserving water
  • Acids produced during carbon fixation diffuse to
    specialized cells surrounding bundle sheath.

11
C4 Photosynthesis
12
Photosynthetic Pathways
  • CAM Photosynthesis
  • (Crassulacean Acid Metabolism)
  • Limited to succulent plants in arid and semi-arid
    environments.
  • Carbon fixation takes place at night.
  • Reduced water loss.
  • Low rates of photosynthesis.
  • Extremely high rates of water use efficiency.

13
CAM Photosynthesis
14
Heterotrophic energy paths Using Organic
Molecules
  • Three Feeding Methods of Heterotrophs
  • Herbivores Feed on plants.
  • Carnivores Feed on animal flesh.
  • Detritivores Feed on non-living organic matter.

15
Chemical Composition and Nutrient Requirements
  • Five elements make up 93-97 of biomass of
    plants, animals, fungi and bacteria
  • Carbon (COOH, ECT) all organic molecules
  • Oxygen C0 almost all organics
  • Hydrogen CH4 almost all organics
  • Nitrogen NH3 protein
  • Phosphorus P- BONES, TEETH
  • All must either ingest or manufacture these
    organic molecules.

16
What function does each macronutrient serve for
living things?
  • Carbon structural for fats, carbs and protein
  • Oxygen oxidation energy production
  • structural
  • Hydrogen structural, energy
  • Nitrogen DNA, proteins
  • Phosphorus energy, APT

17
Essential Plant Nutrients and needed as
supplements for non-plants (worksheet)
  • Potassium
  • Calcium
  • Magnesium
  • Sulfur
  • Chlorine
  • Iron
  • Carbon
  • Nitrogen
  • Phosphorus

18
Problems with Herbivores
  • Substantial nutritional chemistry problems.
  • Low nitrogen concentrations.
  • Must overcome plant physical and chemical
    defenses.
  • Physical - Cellulose lignin silica
  • Chemical Toxins, Digestion Reducing Compounds
    (seeds)

19
Carnivores
  • Must consume nutritionally-rich prey. Energy in
    must be greater than energy out. Problems
  • Major energy input to catch, kill and eat prey
  • Cannot choose prey at will.
  • Prey Defenses
  • Aposomatic Coloring - Warning colors.
  • mimicry

20
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 - size selection.
  • Predator and prey species are engaged in a
    co-evolutionary race.

21
Detritivores
  • Consume food rich in carbon and energy, but poor
    in nitrogen.
  • Dead leaves may have half nitrogen content of
    living leaves.
  • Fresh detritus may still have considerable
    chemical defenses present.

22
Using Inorganic Molecules - chemotrophs
  • 1977 - Organisms found living on sea floor.
  • Near nutrients discharged from volcanic activity
    through oceanic rift.
  • Autotrophs depend on chemosynthetic sulfur
    bacteria.

23
  • 2 types Free-living forms living within
    tissue of invertebrates.

24
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.
  • Consumers require little or no search and
    handling time.
  • 2. Feeding rate rises in proportion to food
    density.
  • Feeding rate partially limited by search/handling
    time.

25
Food Density and Animal Functional Response
  • 3. Feeding rate increases most rapidly at
    intermediate densities
  • (S-shaped).

26
Optimal Foraging Theory
  • Assures if energy supplies are limited, organisms
    cannot simultaneously maximize all life
    functions.
  • Must compromise between competing demands for
    resources.
  • Principle of Allocation

27
Optimal Foraging Theory
  • All other things being equal,more abundant prey
    yields larger energy return. Must consider energy
    expended during
  • Search for prey
  • Handling time
  • Tend to maximize rate of energy intake.

28
Optimal Foraging in Bluegill Sunfish
29
Optimal Foraging By Plants
  • Limited supplies of energy for allocation to
    leaves, stems and roots.
  • 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
    shortest supply.

30
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