energy in living systems. energy i: the facts all organisms transform energy energy = the capacity...
TRANSCRIPT
Energy in Living systems
Energy I: The facts
• All organisms transform energy• Energy = the capacity to do work• Familiar with Kinetic (motion) and Potential
(capacity) energy types• In living organisms Chemical energy is
important• Conversions of chemical energy are the basis
of life
Energy II: The laws
• We deal with either Closed or Open systems• 1st Law: Energy can be transferred and
transformed but it can never be created nor destroyed
• 2nd Law: Every energy transfer or transformation increases the entropy of the universe (e.g. creating heat)
6 Types of Energy
• Radiant – Light (photons)• Nuclear – contained in nuclear attraction
between protons and neutrons• Chemical – Stored in the bonds between
atoms in molecules• Mechanical – motion of objects• Thermal – heat energy in the movement of
molecules• Electrical – movement of electrons
Radiant Energy
Figure 3-10Page 52
Ener
gy e
mitt
ed fr
om s
un (K
cal/
cm2 /
min
)
0
5
10
15
0.25 1 2 2.5 3
Wavelength (micrometers)
Nuclear energy
Chemical energy
Thermal energy
Electrical energy
Transformation of Energy
Solarenergy
Wasteheat
Chemicalenergy
(photosynthesis)
Wasteheat
Wasteheat
Wasteheat
Chemicalenergy(food)
Mechanicalenergy(moving,thinking,
living)
The Quality of Energy
• An energy source’s ability to do useful work• High Quality: (1) organized, (2) concentrated,
(3) can perform useful work
• Low Quality: (1) disorganized, (2) dispersed, (3) little ability to do useful work
Energy Examples
High Quality Energy
1. Electricity2. Chemical E stored in coal
and gas3. Concentrated sunlight4. Nuclei of U-2355. Concentrated Heat
Low Quality Energy
1. Heat in dispersed in the atmosphere
2. Heat stored in an ocean
ElectricityVery–high-temperature heat (greater than 2,500°C)Nuclear fission (uranium)Nuclear fusion (deuterium)Concentrated sunlightHigh-velocity wind
High-temperature heat (1,000–2,500°C)Hydrogen gasNatural gasGasolineCoalFood
Normal sunlightModerate-velocity windHigh-velocity water flowConcentrated geothermal energyModerate-temperature heat (100–1,000°C)Wood and crop wastes
Dispersed geothermal energyLow-temperature heat (100°C or lower)
Very high
High
Moderate
Low
Source of Energy Relative Energy Quality(usefulness)
Energy Tasks
Very–high-temperature heat (greater than 2,500°C) for industrial processes and producing electricity to run electrical devices (lights, motors)
Mechanical motion (to move vehicles and other things)High-temperature heat (1,000–2,500°C) for industrial processes and producing electricity
Moderate-temperature heat (100–1,000°C) for industrial processes, cooking, producing steam, electricity, and hot water
Low-temperature heat(100°C or less) for
space heating
© 2004 Brooks/Cole – Thom
son Learning
The Source of All energy on Earth is the …
The sun
• Lights and warms the planet• Supports photosynthesis radiant energy
converted into chemical energy by plants, protists and bacteria
• Powers the cycling of matter• Drives climate and weather systems
distributing heat and fresh water on earth
What is the sun?
• 72% hydrogen, 28% helium• Temp and pressure high so H nuclei fuse to form
He releasing energy• Fusion energy radiated as electromagnetic
energy• Earth receives 1 billionth of the suns Energy• Most reflected away or absorbed by atmospheric
chemicals
Energy to Earth• 34% solar energy reflected back into space by
atmosphere (albedo effect)• 66% remaining– Warms troposphere and land– Evaporates and cycles water– Generates wind
• 0.023% captured by producers for photosynthesis
• Energy eventually transformed to heat and trapped by atmosphere “Natural Greenhouse Effect”
