Energy
Dec 27, 2015
Energy is defined as the ability to do work.
Work is causing a change that would not otherwise occur.
Energy FormsKinetic energy = energy of motion
Light energy = electromagnetic radiation energy that travels through space as waves
Potential energy = stored energy
Chemical energy = energy stored in molecules in the bonds between atoms
What are some other forms of energy?
Potential energycan be convertedinto kinetic energy
Kinetic energy can be converted into potential energy
First Law of EnergyThe First Law of Energy (or conservation
of energy principle) states that energy cannot be created or destroyed. Energy can only be converted from one form to another.
The Second Law of Energy states that when energy is converted from one form to another, some energy will be unusable, usually lost as heat.
Cellular Respiration
Cellular Respiration is the harvesting of chemical energy from organic fuel molecules (i.e. glucose) and converting that energy into the chemical energy in ATP molecules.
Aerobic cellular respiration
requires oxygen (O2)
Aerobic Cellular Respiration Net Chemical Equation
Can produce 38 ATP
from the energy in ONE Glucose
Aerobic Cellular Respiration
In your body cells;
Where does the Glucose come from?
Where does the Oxygen (O2) come from?
Where does the carbon dioxide (CO2) go?
Aerobic Cellular Respiration
If one glucose molecule contains 686 kcal
and
One ATP molecule contains 7.5 kcal
What is the energy efficiency of aerobic cellular respiration?
What has happened to the remaining energy?
Anaerobic Cellular Respiration harvests energy from food without oxygen.
Fermentation is the most common type of anaerobic cellular respiration.
Fermentation occurs in botheukaryotic and prokaryotic cells.
Anaerobic Cellular Respiration
Fermentation in Microorganisms
Anaerobes are organisms that conduct anaerobic cellular respiration.
Facultative Anaerobes can conduct either aerobic or anaerobic cellular respiration.
Obligate Anaerobes can only conduct anaerobic, and are actually poisoned by oxygen.
PhotosynthesisPhotosynthesis is the process where
green plants (& some bacteria) convert
light energy into the chemical energy contained in glucose molecules.
Glucose produced is used for;
• Cellular Respiration
• Starch (stored glucose)
• Cellulose (structural)
• Other Organic Compounds
Solar-Driven Evolution
Plants that use CO2 directly from the air are called C3 plants (CO2 binds to a three carbon molecule when it enters the plants cells)
Common crops like oats, wheat, soybeans and rice
C3 plants close their stomata on hot, dry days to reduce the loss of water, but this also prevents CO2 from entering the leaves. Why is this a problem?
Alternate modes of incorporating carbon from CO2 have evolved in some plants, allowing them to save water without shutting down photostnthesis.
C4 plants are named for the four-carbon molecule that CO2 binds with inside the cell.
This molecule then shuttles the CO2 to a nearby cell, which can keep on making sugars even if the stomata are closed on a hot, dry day.
Corn and sugarcane are examples
CAM plants have adapted to very dry climates by opening their stomata and admitting CO2 only at night.
CO2 binds a four-carbon molecule at night and releases the CO2 in the same cell for photosynthesis during the day.
Examples are pineapples, cacti, and succulents like aloe and jade.
Food Chain = sequence of food transfers from producers thru several levels of consumers
Trophic Levels = eating levels in a food chain
• Quaternary Consumer• Tertiary Consumer• Secondary Consumer• Primary Consumer• Producer
Decomposers / DetritivoresDetritus = animal wastes, plant litter (detritus), and dead
organisms
Detritivores eat detritus, and by breaking it down into molecules that other organisms can use they recycle these nutrients.
Termites
Biomass
Biomass = the weight, or mass, of organic material in an ecosystem
Biomass can be determined for a trophic level, as well as whole ecosystem
Example; The weight of all the plants equals the biomass of the producers
Primary Productivity = the rate at which plants and other producers build biomass, or organic matter in an ecosystem
The primary productivity of the entire biosphere is about 170 billion tons of organic material per year
Remember the Second Law of Energy states that when energy is converted from one form to another, some energy will be unusable, usually lost as heat.On average, only about 10% of the energy eaten at each trophic level is stored as biomass in the next trophic level
Biogeochemical Cycles = any of the chemical circuits occurring in an ecosystem, involving both biotic and abiotic components of the ecosystem
Examples of Biogeochemical Cycles
• Carbon Cycle
• Nitrogen Cycle
• Phosphorus Cycle
• Water (Hydrologic) Cycle
The Greenhouse Effect
Greenhouse Effect = Warming of atmosphere
caused by greenhouse gases, like
CO2, CH4 and others that absorb heat
and slow its escape from the Earth’s surface.
Carbon Dioxide or CO2
is the principle greenhouse gas
The Greenhouse EffectCO2 and other greenhouse gases act like
clear glass in a greenhouse or your car.
Normally this is beneficial because it increases average temperatures by about 10oC (18oF) making the Earth livable.
The Industrial Revolution, which began about 1800, was the shift from an economy based on manual labor to one dominated by industry with steam powered machinery (fueled primarily by coal).
Steam-powered ships, railways, the internal combustion engine and electrical power generation were all developed by 1900 .
Since the Industrial Revolution
the amount of CO2 in the atmosphere
has increased about 30%,
mostly from burning fossil fuels.
Global WarmingAt the present rate of increase by 2075 the
amount of CO2 in the atmosphere will be double the amount at the start of the Industrial Revolution.
If CO2 does double by 2075 it is predicted
that the world’s average temperature
will increase by almost 4°F.
If it only rises 2°F it would be warmer than anytime in the last 100,000 years.
2005 0.6183 0.9593 0.4896
2010 0.6171 0.9642 0.4885
1998 0.5984 0.8320 0.5090
2003 0.5832 0.7735 0.5108
2002 0.5762 0.8318 0.4798
2006 0.5623 0.8158 0.4669
2009 0.5591 0.7595 0.4848
2007 0.5509 0.9852 0.3900
2004 0.5441 0.7115 0.4819
2001 0.5188 0.7207 0.4419
2008 0.4842 0.7801 0.3745
1997 0.4799 0.5583 0.4502
1999 0.4210 0.6759 0.3240
1995 0.4097 0.6533 0.3196
2000 0.3899 0.5174 0.3409
1990 0.3879 0.5479 0.3283
1991 0.3380 0.4087 0.3110
1988 0.3028 0.4192 0.2595
1987 0.2991 0.2959 0.3005
1994 0.2954 0.3604 0.2704
1983 0.2839 0.3715 0.2513
20 warmest years on record 1901–2000
What Will Happen?= Global Climate Change
Melting of Polar Ice (including Greenland)
will raise sea level by 100 meters,
which will flood coastal areas.
For example, Miami, New York, Los Angeles
will all be underwater.
Climate Change
Our major agricultural area,
the central part of the United States,
will become much drier.
Climate ChangeMost natural ecosystems will be affected
based on predictions from mathematical models.
Study of prehistoric periods of warming & cooling shows that the types and numbers of plants were
altered dramatically by climate changes.
Past climate changes were very gradual, so plants and animals could spread into areas where conditions
allowed them to survive.
The concern is that global climate change today is too rapid, so plants and animals may not be able to survive.
A Miracle?What if we had some living things on Earth
that would remove carbon dioxide
from the atmosphere?
What if we had lots of these organisms living all over the Earth?
We Do ! They are called PLANTS.
Plants use CO2 to make sugars
during the process of photosynthesis.
DeforestationDeforestation is the change of forest land to
non-forest land such as;Farmland
Cities
Logged areas
Wasteland
Deforestation = Cutting down trees
Less trees = Less Photosynthesis
DeforestationLess Photosynthesis means less CO2
being removed from the atmosphere.
Plus, the burning of trees after
deforestation to clear land in the tropics
adds about 20% of the total excess CO2
into the atmosphere.
The other 80% of excess CO2
is from burning fossil fuels.
What Can Be Done?Reduce deforestation, particularly in areas like the tropics, NW and SE United States, Canada and Siberia.
What Can Be Done?
Since fossil fuels power industry and
economic growth it will not be easy.
It will require strong individual commitment & acceptance of major lifestyle changes.
The U. S. consumes more energy
than the TOTAL populations of
Central America, South America,
Africa, India and China.
That is almost 4 billion people
versus only about 300 million
people in the U. S. !
Moderation of global climate change depends mainly on the richest countries
reducing their use of fossil fuels
by conserving energy and developing alternative energy sources
like wind, solar,
and geothermal.
Individually we must become
more energy-efficient at home
and reduce our reliance on the
automobile.