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 1 st Law: Energy can be transferred and transformed but it can never be created nor destroyed 2 nd 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 3-10 Page 52 Energy emitted from sun (Kcal/cm 2 /min) Wavelength (micrometers)

Nuclear energy

Chemical energy

Mechanical energy

Thermal energy

Electrical energy

Transformation of Energy Solar energy Waste heat Chemical energy (photosynthesis) Waste heat Waste heat Waste heat Chemical energy (food) Mechanical energy (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.Electricity 2.Chemical E stored in coal and gas 3.Concentrated sunlight 4.Nuclei of U Concentrated Heat Low Quality Energy 1.Heat in dispersed in the atmosphere 2.Heat stored in an ocean

Electricity Very–high-temperature heat (greater than 2,500°C) Nuclear fission (uranium) Nuclear fusion (deuterium) Concentrated sunlight High-velocity wind High-temperature heat (1,000–2,500°C) Hydrogen gas Natural gas Gasoline Coal Food Normal sunlight Moderate-velocity wind High-velocity water flow Concentrated geothermal energy Moderate-temperature heat (100–1,000°C) Wood and crop wastes Dispersed geothermal energy Low-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 – Thomson 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”