1. 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

2. Other significant events:
Paleozoic Era:
Carboniferous period – current coal and oil deposits went into ground to begin forming
325 million years ago
Life is beginning to transition from sea to land

3. Mesozoic Era: Cenozoic Era: Reptiles ruled and mammals arose
Mammals began to thrive
Current times

4. How Things Have Changed Since Humans

5. Agricultural Revolution
10,000-12,000 years ago
Shift from nomads to settled communities
Domesticated plants and animals

6. Industrial Revolution
18th-19th centuries
Movement from farms to cities because of mechanized equipment
Movement from renewable energy to nonrenewable energy
Prior to IR, biomass fuels (wood) were most common fuel source

7. Frontier Mentality
America was treated as a place with unlimited resources with infinite supplies around 1800s to even now

8. Late 1800’s – movement towards preserving the environment
John Muir – Sierra Club; preservationist movement
Teddy Roosevelt – 1st president to take a stand for the environment ( )
First wildlife refuge
Expanded national forests
Gave President power to take land for preservation
Conservationist

9. Until 1960s FDR created CCC for post war jobs – environmentally based
CFCs began to be used as refrigerants
Discovery of penicillin
New classes of synthetic pesticides were produced
Air, water, soil quality was changing, but nothing was really being done about it

10. 1960s until now
1962 – Silent Spring by Rachel Carson is published; wrote of effects of DDT on life, water, etc. – considered beginning of environmental revolution

11. Richard Nixon
Created Environmental Protection Agency
Signed Endangered Species Act
Jimmy Carter
Created Department of Energy
Reagan, G. HW Bush, G.W. Bush
Saw a more “anti-environmental” movement
Clinton
Major push for fuel economy standards; initially signed Kyoto Protocol (GHG emissions) but Senate refused to back it

12. How does a system work?
Parts working together to form a whole

13. The Earth

14. Earth’s Atmosphere
Blanket of gases that surround Earth

15. The Geosphere Lithosphere (crust) Asthenosphere / mantle Outer core
Inner core

16. The Hydrosphere
All of Earth’s water
Both saltwater and freshwater

17. The Biosphere All life on Earth
All other spheres feed into this system and the converse

18. The Sun How does the Sun work? How does the Sun’s energy reach Earth?
Hydrogen fusion that forms helium and releases radiation as a result
How does the Sun’s energy reach Earth?
The Sun’s energy reaches Earth in the form of electromagnetic waves (mainly infrared, visible, and ultraviolet here on Earth)

19. Why is the Sun’s radiation important to us?
Heats the Earth so that we can live on it (Biosphere)
Causes weather processes to occur (Hydro and atmosphere)

20. Earth’s Place in the Solar System
3rd planet from the Sun
Only one able to support life
Daily impact from our place in the solar system?
Seasons

21. Seasons Due to Earth’s tilt (23.5°) and revolution around Sun
The same amount of sunlight travels towards Earth all year round, but tilt is large reason for seasons
Summer
Fall
Winter
Spring

22. Feedback Loops Positive feedback Negative feedback
Runaway cycle in one direction
Negative feedback
System keeps itself in check
Body temperature; thermostats

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

24. Time Delays
Any sort of event that takes a long time for a response or action to occur
CFCs depleting the ozone layer
A smoker developing lung cancer

25. Laws of Thermodynamics
First Law of Thermodynamics
Energy is not created or destroyed, just changed.
Example – a pendulum swinging in a vacuum (kinetic vs. potential energy)
- Input = output

26. 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

27. Ecology How does the biosphere break down?
Biosphere (Broadest) – all living and nonliving parts of the environment
Ecosystem – populations in a specific region interacting with their nonliving surroundings
Community – different populations of organisms in a specific area (habitat)
Population – a group of members of the same species of organism
Species (Most specific) – a group of organisms that can interbreed with one another and produce a viable offspring

28. Biomass
Anything within the ecosystem that is considered a fuel resource
It can also refer to the dry mass of the organisms in the ecosystem

29. FOOD WEBS AND ENERGY FLOW IN ECOSYSTEMS
Food Chain – linear sequence of organisms, each of which is a source of food for the next
Food Web – complex network of interconnected food chains in an ecosystem
Trophic Level – feeding level that organisms are assigned to depending on classification as producer or consumer (or what level consumer)
Producers belong to the first trophic level
Primary consumers to the second trophic level
Secondary consumers to the third, etc
Each trophic level contains a certain amount of biomass
**Only about 10% of energy is passed from level to another

30. How Producers Produce
Photosynthesis – process for using sunlight to make carbohydrates.
Chemosynthesis – process in which inorganic carbon compounds or other inorganic compounds are converted to carbohydrates without sunlight

31. Feeding relationships and energy
Tertiary consumers
Secondary consumers
Primary consumers
Producers

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

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

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

35. 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

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

37. EARTH’S BIOGEOCHEMICAL CYCLES
Nutrient atoms, ions, and molecules are cycled continuously
Water Cycle – collects, purifies, and distributes the earth’s fixed supply of water
Carbon Cycle – a global gaseous cycle, is based on carbon dioxide gas
Nitrogen Cycle – cyclic movement of nitrogen in different chemical forms from the environment to organisms and then back to the environment
Phosphorus Cycle – phosphorus circulates through water, the earth’s crust, and living organisms
Sulfur Cycle – gaseous cycle; much of the earth’s sulfur is stored underground in rocks and minerals, including sulfate salts in ocean sediments.

38. Water Cycle Evaporation Transpiration Condensation Precipitation
Infiltration (movement of water into soil)
Percolation - when water soaks through ground to reach aquifer
Runoff (surface water goes back to the ocean, lake)

39. Human Impact on Water Cycle
Direct
We’ve created MAJOR pollution issues
Indirectly
Accelerated climate change can cause changes in weather patterns

40. Carbon Cycle
Producers remove CO2 from the atmosphere through photosynthesis
Consumers use glucose during aerobic respiration and carbon dioxide is produced as a waste gas
Cycles through atmosphere quickly but stays stored in the ocean for longer periods of time

41. Human Impact On Carbon Cycle
Major impact through burning fossil fuels

42. 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

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

44. Third Step: ASSIMILATION – plant roots absorb ammonia, ammonium, and nitrate needed for growth.
Fourth Step: AMMONIFICATION –Specialized decomposer bacteria convert animal wastes and dead organisms into ammonia, and ammonium salts

45. Fifth Step: DENITRIFICATION: Bacteria convert ammonia and ammonium back into nitrite and nitrate ions and then into nitrogen gas

46. Importance of Nitrogen Cycle
One of two most essential nutrients to ecosystems
Limiting factor of growth
Human Impact - Nitrogen “pollution” comes from human usage with fertilizer – can cause eutrophication (depletes oxygen from water supply)

47. Phosphorus Cycle
Phosphorus moves slowly from phosphate deposits on land and in oceans
Phosphorous leaches from rock and dissolves in water or undergoes weathering and is dissolved in ocean water. Cycles through the marine food webs
**NO GASEOUS PHASE EVER**
Other nutrient essential to ecosystems because it can limit growth as well
Can also contribute to eutrophication (humans)

48. Sulfur Cycle
Sulfur enters the atmosphere from several natural sources.
Hydrogen sulfide is released from active volcanoes
Breakdown of organic matter in swamps, bogs, and tidal flats during decomposition
In the atmosphere, hydrogen sulfide changes to sulfur dioxide and sulfur trioxide as it reacts with oxygen. Some reacts with water droplets in the atmosphere to produce droplets of sulfuric acid or sulfate salts

49. Human Impact
Burning fossil fuels (coal specifically) we release more sulfur into the atmosphere

50. ECOSYSTEM CONCEPTS AND COMPONENTS
Biome – Regions inhabited by certain types of life, distinguished especially by vegetation.
Climate – patterns of weather – determines what type of life will thrive in a given land area
Ecotone – a region containing a mixture of species from adjacent ecosystems and often species not found in either of the bordering ecosystems.