1. Earth’s Spheres 4 spheres 1. Geosphere – physical Earth
Sometimes called lithosphere (outer crust)
2. Atmosphere – blanket of gas surrounding the planet
3. Hydrosphere – All of Earth’s water
4. Biosphere – all living things

2. Our Place in the Solar System
3rd Planet from the Sun
We have seasons due to our tilt and revolution around the Sun

4. Earth’s History How old is Earth believed to be?
4.6 billion years old
What are some of the most significant events in Earth’s history?
~3.5 billion years ago – first cells formed
2 bya – Oxygen Revolution
1.8 bya – first eukaryotic cells appeared

5. Other significant events:
Paleozoic Era:
Carboniferous period – current coal and oil deposits went into ground to begin forming (325 mya)
Life transitions from sea to land

6. Mesozoic Era: Cenozoic Era: Reptiles dominate and mammals arose
Mammals began to thrive

7. Agricultural Revolution
10,000-12,000 years ago
Domestication of plants and animals
Nomads  communities

8. Industrial Revolution
18th-19th centuries
Movement from renewable energy to nonrenewable energy
Prior to IR, biomass fuels (wood) most common

9. Feedback Loops Positive feedback Negative feedback
Runaway cycle in one direction
Negative feedback
System keeps itself in check

10. Synergy
The sum of two parts is greater than the two individually

11. Time Delays
Any sort of event that takes a long time for a response or action to occur

12. Laws of Thermodynamics
First Law of Thermodynamics
Energy is not created or destroyed, just changed.
- Input = output

13. 2nd Law of Thermodynamics
Energy transfer is never 100% efficient – some will be lost to environment as heat
An incandescent light bulb gives off about 95% of the energy used to power it as heat

16. Biomass Anything within the ecosystem considered a fuel resource
Also the dry mass of organisms in the ecosystem

17. Ecological Pyramids
Pyramid of Numbers – shows population of each level in a food chain

18. Pyramid of Biomass
Shows the amount of biomass (dry weight of organisms) present at each trophic level in a food chain

19. Pyramid of Energy
Drawn to show energy utilized at each trophic level

20. PRODUCTIVITY OF ECOSYSTEMS
Gross Primary Productivity (GPP) –Rate at which an producers capture and store chemical energy as biomass in a given time period
Net Primary Productivity (NPP) – The rate at which primary producers accumulate net useful chemical energy
NPP = (Rate at which producers store chemical energy as biomass) – (Rate at which producers use some energy for respiration)
NPP = GPP – Plant respiration

21. Productive Ecosystems
Two most productive ecosystems on Earth:
Wetlands
Rain forests
Least productive:
The ocean (as a whole)
Deserts

22. Biogeochemical Cycles
Type of Cycle
Major Storage Area
Water
In the oceans
Carbon
Dissolved into the oceans
Phosphorous
In Earth’s crust as rock
Sulfur
In Earth’s crust within rocks and minerals
Nitrogen
In the atmosphere

23. Nitrogen Cycle – *MUST KNOW*
First Step: NITROGEN FIXATION: Bacteria (cyanobacteria (soil and H2O) and Rhizobium (roots)) convert gaseous nitrogen to ammonia that can be used by plants.
N2 + 3H2 -> 2NH3
Nitrogen can also be fixed through lightning
3N2 + 6H2O -> 4NH3 + 2NO3

24. Second Step: NITRIFICATION:
Ammonia is converted by Nitrosomonas to nitrite ions
2NH3 + 3O2 -> 2NO2 + 2H+ + 2H2O
Nitrobacter convert nitrite to nitrate ions, which are easily taken up by plants as a nutrient.
2NO2- + O2 -> 2NO3-

25. Third Step: ASSIMILATION – plant roots absorb nitrites, ammonium, and nitrates needed for growth.
Fourth Step: AMMONIFICATION –Specialized decomposer bacteria convert animal wastes and dead organisms into ammonium

26. Fifth Step: DENITRIFICATION: Bacteria (Pseudomonas) convert nitrates back into nitrogen gas