Earth is a peculiar planet.
-Water
-Water at all the phases
-Plate Tectonics
-Life
-Planets Near Earth
-Inner Planets
-Earth,Mars,Mercury (has little atmosphere) and Venus (has hyperactive
atmosphere)
-Does not have the same atmosphere as Earth
-Earth Has "environmental fitness"
-Life altered environment at global level
-Earth's unique atmosphere shows it contains life.
-Rise of Oxygen
-Before 2.3 billion years ago, the Earth's atmosphere had low oxygen
-There are rocks called pyrite made of iron, and when iron is oxidized, it
begins to rust.
-Photosynthesis began the rise of oxygen.
-First things that would photosynthesize: stromatolites (3.4 billion years
old)
-CO2 and Water taken in by plant and added with sunlight, to create
oxygen and sugar.
-Took 2 billion years before oxygen was going into the atmosphere, but it
first had to oxidize the unoxidized iron.
-Early Organisms on Earth
-Prokaryotes
-Had a simple cell structure
-Lacked organelles and nucleus
-Took to much energy to maintain
-Get their energy from fermentation
-Low energy yield
-Waste CO2 and alcohol
-Live single, or had end-to-end chains
-Cannot become 3-D structures
-Eukaryotes
-Uses oxygen for respiration
-Had large cells with a nucleus and organelles.
-Can form a 3-D colony of cells
-Evolution of Biosphere
-Began to evolve because of the complexity of the eukaryotes
-Biosphere began to change
-Plants and Animals began to evolve 700-500 million years ago
-Changed the biogeochemical cycle on Earth
-Life and Global Chemical Cells
-Micronutrients
-Elements needed in small amounts by all life, some forms of life need a
moderate amount
-Macronutrients
-24 elements needed by all organisms
-'Big Six': Building blocks of life
-Carbon,oxygen,hydrogen,nitrogen,phosphorus and sulfur.
-Each play a special role in an organism
-For life to continue, elements need to be available in the right time, with the
right amount.
-Too much can be toxic
-Too little can limit growth
-Some elements are neutral for life
-Biogeochemical Cycles
-Complete path a chemical takes through 4 major components of Earth's
system
-Atmosphere, Hydrosphere, Lithosphere, Biosphere
-General Aspects of Biogeochemical Cycles
-Chemicals cycle quickly and are readily regenerated.
-Have a gas phase and is carried by hydrolic cycle, soluble
-Ex:/Oxygen and Nitrogen
-Other elements are immoble and is returned by geological processes
-Lack a gas phase and is insoluble
-Ex:/ Phosphorus
-Most required nutrient is light
-Heaviest is iodine (atomic weight of 53)
-Evolution of live changed the biogeochemical cycles
-Modern tech transfers rate of elements in air, water and soil change
-Can benefit the society but can also be a hazard
-Simplest way to view a cycle: box and arrow diagram
-Boxes: Places where chemical is stored
-Source: Donating compartment
-Sink: Receiving compartment
-Residence Time: Amount of time atom spends in any compartment
-Arrows: pathways of transfer
-Flow: amount moving from one box to another
-Flux: Rate/Speed
-The Geologic Cycle
-Rocks and soil is continually created, maintained, changed and destroyed
the last 4.6 billion years
-Changed due to physical, chemical and biological processes
-Geologic Cycle- Group of Cycles
-Tectonic
-Hydrologic
-Rock
-Biogeochemical
-Tectonic Cycle
-Involves creation/destruction of lithosphere (outer layer of Earth)
-About 100km thick and is broken in several plates
-Slow movement of plates: Plate Tectonics
-Move 2-15cm/year
-Large Scale Effects
-Location and Size of continent
-Change in climate
-Ecological Islands
-Areas of volcanic activity/earthquakes
-Types of Plate Boundaries
-Divergent:Plates move away from each other
-New lithosphere is produced
-Convergent: Plates move into each other
-Heavy ocean plates meeting lighter continental plates will cause a
subduction zone
-Two light plates creates a mountain
-Transform: Plate slides past another
-The Hydrologic Cycle
-Transfer of water from oceans to the atmosphere to land and back to oceans
-Driven by solar energy
-Evaporation-Ocean
-Precipitation-Land
-Transportation-Water by plants
-Evaporation-Land
-Runoff from streams,rivers and subsurface groundwater
-Total water on earth=1.3 billion cubic kilometers
-97% Ocean
-2% Glaciers and Ice caps
-0.001% in atmosphere
-Rest is on freshwater on land
-Fundamental unit of the landscape is a drainage basin
-Area that contributes surface runoff to particular stream or river
-Vary greatly
-Named for main stream or river
-The Rock Cycle
-Has numerous processes that produce rock and soil
-Depends on the tectonic cycle for energy and hydrologic for water
-Rocks: Igneous, Sedimentary, Metamorphic
-Freezing and thawing produces the sediment such as gravel, sand and silt
-Chemical weathering occurs when weak acids in water dissolve chemicals
from rocks.
-The Carbon Cycle
-Carbon is element that anchors all organic substances
-Has a gaseous phase
-Enters atmosphere as CO2 and CH4 through respiration, fire and diffusion
-Is removed from atmosphere by photosynthesis
-Occurs in several forms in ocean
-Dissolved CO2 carbonate and bicarbonate
-Marine organisms produce CaCO3
-Carbon enters ocean by simple diffusion and then dissolve/transfer from
land in rivers as dissolved carbon/Wind.
-Carbon enters biota (life) through photosynthesis and returned by fire or
respiration
-Dead organism decomposes and released carbon
-Buried under certain conditions: carbon not released
-Turns into fossil fuels
-The Carbon-Silicate Cycle
-Cycling of carbon is intimately involved with cycling of silicon
-Carbonic acid falls as rain and weathers silicate rich rocks
-Transferred into oceans and is used by marine animals to make shells
-Ca^2+(Calcium) and HCO3- (Bicarbonate)
-Shells deposited on sea floor and become part of the sedimentary rock layer
and returns to surface in subduction zones
-Affects CO2 and O2 in atmosphere
-The Nitrogen Cycle
-Nitrogen is essential to life because it is need for protein and DNA
-N2 makes up 78% of atmosphere
-Most organisms can't use it directly
-Unreactive element and must be converted to NO3-(Nitrate) and NH4+
(Immonia)
-Performed by bacteria
-Nitrogen fixation: process of converting atmospheric N to NO3- or NH4+
-Denitrification- process o releasing fixed N back to molecular N (Soil to
atmosphere)
-Almost all organisms depend on N converting bacteria
-Formed symbiotic relationship in roots of plants/animal stomach
-Without it, we can't use the nitrogen
-Industrial processing can now convert molecular N into compounds that can
be used by the plants
-Main component of nitrogen fertilizers
-Nitrogen in agricultural runoff is a potential source of water pollution
-Nitrogen and Oxygen combine at high temps
-Oxide of Nitrogen is a source of air pollution
-Phosphorus Cycle
-Often a limiting factor for plants and algal growth
-No gaseous phase
-Low transfer rate
-Enters life through uptake by plants, algae and bacteria
-Goes back to soil when the plants die/ lost to oceans by runoff
-Returned to land by feeding birds (guano)
-Guano deposits a major source of Phosphorus for the fertilizers