Energy for Life The Basics of Energy and How it Relates to Ecosystems

Energy Energy provides the force to hold structures together, tear them apart, and move them from one place to a another. It is the ability to do work. Moving matter over a distance Causing a heat transfer between two objects at different temperatures

Forms of Energy Energy can take on many different forms Heat Light Electricity Chemical (eg. Photosynthesis and respiration)

Forms of Energy Kinetic energy is energy contained in moving objects. Rolling down a hill. Water flowing over a dam.

Forms of Energy Potential Energy is stored energy that is latent but available for use. Eg. Water stored behind a dam.

Heat Energy is measured in units of heat (calories) or work (joules) Heat describes the energy that can be transferred between objects of different temperature. (change in heat content = change in temperature, usually)

Thermodynamics Energy transfer through an ecosystem is ONE WAY Most energy is lost as heat Most energy comes from the A constant supply of energy is needed to keep biological process running.

Thermodynamics The study of thermodynamics deals with how energy is transferred in natural processes. It deals with the rates of flow and transformation of energy from one form to another.

Thermodynamics First Law of Thermodynamics Energy is conserved—it is neither created nor destroyed, rather it changes from one form to another Eg. Electrical to heat energy Therefore the same amount of the energy that goes into a system, leaves the system.

Thermodynamics Second Law of Thermodynamics With each successive energy transfer, less energy is available to do work. The energy is degraded to lower quality forms or It is lost as heat-- dissipates

Environmental Consequence of Thermodynamics A consequence of energy conversion is pollution. e.g burning gas to release its energy—byproduct is harmful chemicals (NO3, CO2, Ozone) released into the air.

Entropy The Second Law of Thermodynamics recognizes that disorder tends to increase in all natural systems, therefore less useful energy is available when you finish a process than there was before you started. This is called entropy. Houses fall into ruin, cars rust, appliances wear out. (produce heat as they degrade)

Energy Flow Diagrams Show how nutrients are cycled through the ecosystem, and how much of the energy is “lost” as heat. Yellow arrows = energy Blue arrows = nutrients Arrow width can vary to represent flow quantity, although this diagram does not illustrate this. Boxes = storages

Energy Flow Diagram

Energy for Life Where does energy come from? Chemosynthesis Photosynthesis Cellular Respiration

Chemosynthesis The energy source used by organisms at the bottom of the ocean. The process in which inorganic compounds (eg. Hydrogen sulfide) serve as an energy source for synthesis or organic molecules

Photosynthesis Converts radiant energy into chemical energy in the bonds that hold together organic molecules (i.e. glucose)

Photosynthesis Only 1 to 2 % of sunlight reaching the earth is taken by photosynthesis (the rest is reflected or absorbed by the earth or is inappropriate for photosynthesis) This is the energy base for all of life on earth

Photosynthesis Photosynthesis equation

Cellular Respiration Cellular respiration is the opposite of photosynthesis and it used by both autotrophs and animals.

Specific Heat The specific heat of a substance is the ability of a substance to absorb heat. Example: the specific heat of water is 4.18 Joules This means that is takes 4.18 Joules of energy to increase 1 gram of water by 1 degree celsius. The specific heat of a substance is constant. This does not mean the temperature of the substance cannot change—it means that the amount of energy to change the temperature remains the same.

Homework Pre—lab the Specific Heat and Climate Lab