Ecosystems and Livig

Organisms

Chapter 4

The Gaia TheoryDynamic Equilibrium

Negative Feedback

Positive Feedback

The Gaia Theory: The organic and inorganic components of Planet Earth have evolved together as a single living, self-regulating system.

In a phrase, “life maintains conditions suitable for its own survival.”

Biogeochemical Cycle

The complete path a chemical takesthrough the three primary reservoirs or“sinks” of Earth’s systems:

1. Atmosphere2. Hydrosphere3. Lithosphere

CyclesCarbon1.Lipids2.Nucleic Acids3.Carbohydrates4.Amino Acids

Nitrogen1.Amino Acids

Phosphorus1.ATP2.DNA3. Cell Membranes

Sulfur1.Amino Acids2.Keratin

Fixed amounts of all elements on earth * Oxidation describes the loss of electrons by a molecule, atom or ion * Reduction describes the gain of electrons by a molecule, atom or ion

Carbon Cycle

Billions of Tons

http://www.youtube.com/watch?v=0Vwa6qtEih8&feature=related

Carbon Silicate

A weathering Cycle:1.Atmospheric CO2 forms H2CO3 (Carbonic Acid) precipitation which moves through soil2.H2CO3 dissociates & forms H+ & HCO -

3 (bicarbonate)3.Silicate rich minerals interact with the free H+ to release Ca2+

4.Shellfish5.Subduction – silicate formation at temperatures above 300 °C

Carbon Silicate

Believed to provide important negative feedback mechanisms that control the temperature of the atmosphere.

Nitrogen cycleNitrogen cycle: Atmospheric

nitrogen (N2)

Nitrogen fixation by humans

Biological nitrogen 1. fixation

2. Nitrification

NH3 & NH4

-

NO3-

3. Assimilation

5.DenitrificationPlant & animal proteins

Decomposition - urea

4. Ammonification

Internal cycling

(Ammonia)

LightningVolcanoesBacteria

(Nitrates &Nitrites)

(Oxidation)

NO3 - → NO

2 - → NO → N2O → N

2 gas

Nitrogen Cycle & Steps1. Nitrogen Fixation is the conversion of elemental

nitrogen(N2) to organic ammonia(NH3) by bacteria, lightning, industry, volcanoes.

2. Nitrification - conversion of ammonia or ammonium (NH4) into nitrites(NO-

2) and then into nitrates (NO-3) by

bacteria3. Assimilation- plants absorb nitrates or ammonia4. Ammonification - nitrogen is converted into ammonia

from animal waste or dead organisms by aerobic bacteria5. Denitrification - anaerobic bacteria convert nitrates &

nitrites to nitrogen gasses off to atmosphere1. Nitrogen is not a reactive molecule2. 78% atmosphere N2 & 21% oxygen & .038% CO2

YouTube: http://www.youtube.com/watch?v=m4YToXw724w&feature=related

Phosphorus Cycle

Does not include the atmosphereYouTube: http://www.youtube.com/watch?v=RKkC2JpjaGc&feature=related

Phosphorus Cycle

Phosphorus

Brazil

Guano

Accelerated Eutrophication

Cycling of Materials within EcosystemsSulfur cycle:

YouTube: http://www.youtube.com/watch?v=BzPeA9oQNl8

Cycling of Materials within EcosystemsHydrologic cycle: