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Energy - PowerPoint PPT Presentation

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Energy. Energy is defined as the ability to do work. Work is causing a change that would not otherwise occur. Energy Forms. Kinetic energy = energy of motion Light energy = electromagnetic radiation energy that travels through space as waves Potential energy = stored energy

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Presentation Transcript
Energy is defined as the ability to do work.
  • Work is causing a change that would not otherwise occur.
energy forms
Energy Forms
  • Kinetic 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 energy

can be converted

into kinetic energy

Kinetic energy can be converted into potential energy

first law of energy
First Law of Energy
  • The 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.
  • ATP is the source of chemical energy for cellular work.
the atp cycle
The ATP Cycle

This is really important !

cellular respiration
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
Aerobic Cellular Respiration Net Chemical Equation
  • Can produce 38 ATP
  • from the energy in ONE Glucose
aerobic cellular respiration
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 respiration1
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
Anaerobic Cellular Respiration
  • Anaerobic Cellular Respiration harvests energy from food without oxygen.
  • Fermentation is the most common type of anaerobic cellular respiration.
  • Fermentation occurs in both
  • eukaryotic and prokaryotic cells.
fermentation in microorganisms
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.

Photosynthesis is the process where

green plants (& some bacteria) convert

light energy into the chemical energy contained in glucose molecules.


Oxygen seeking bacteria migrate toward algae

exposed to certain colors of light.

Glucose produced is used for;
  • Cellular Respiration
  • Starch (stored glucose)
  • Cellulose (structural)
  • Other Organic Compounds
energy flow
Energy Flow

Always ONE WAY Flow

  • Sunlight Glucose ATP

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 detritivores
Decomposers / Detritivores
  • Detritus = 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.



Food Web

= a network of interconnecting food chains

  • 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


Why would it be more efficient for humans

to eat more plants and less animals?


Biogeochemical Cycles =any of the chemical circuits occurring in an ecosystem, involving both biotic and abiotic components of the ecosystem

biogeochemical cycles
Biogeochemical Cycles
  • (Community)
  • (Physical Environment)
Examples of Biogeochemical Cycles
  • Carbon Cycle
  • Nitrogen Cycle
  • Phosphorus Cycle
  • Water (Hydrologic) Cycle
the greenhouse effect
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 effect1
The Greenhouse Effect

CO2 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 .

fossil fuels
Fossil Fuels

Coal Oil (gasoline) Natural Gas

Burning fossil fuels releases CO2 into the air

Since the Industrial Revolution

the amount of CO2 in the atmosphere

has increased about 30%,

mostly from burning fossil fuels.

global warming
Global Warming

At 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.

what will happen global climate change
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
Climate Change

Our major agricultural area,

the central part of the United States,

will become much drier.

climate change1
Climate Change

Most 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
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.


Deforestation is the change of forest land to non-forest land such as;



Logged areas


Deforestation = Cutting down trees

Less trees = Less Photosynthesis


Less 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
What Can Be Done?

Reduce deforestation, particularly in areas like the tropics, NW and SE United States, Canada and Siberia.

what can be done1
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.

Developed countries with the most industry

need to take the greatest responsibility.

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.