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

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

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

How Things Have Changed Since Humans

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

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

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

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 (1900-1910) First wildlife refuge Expanded national forests Gave President power to take land for preservation Conservationist

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

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

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

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

The Earth

Earth’s Atmosphere Blanket of gases that surround Earth

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

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

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

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)

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)

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

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

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

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

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

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

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

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

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

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

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

Feeding relationships and energy Tertiary consumers Secondary consumers Primary consumers Producers

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

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

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

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

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

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.

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)

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

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

Human Impact On Carbon Cycle Major impact through burning fossil fuels

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

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-

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

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

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)

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)

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

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

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.