Characteristics of Life

How to determine if something is living…….. Trying to decide if something is alive can be a tricky proposition What are some characteristics of living things?

Characteristics of Life 1. Energy input that is less than energy output 2. Have a high level of organization compared to the environment that it exists 3. Have an organization which structure is related to its function 4. Contains DNA that encodes for the structure and maintaining the organization of that structure 5. Sense and react to changes in the environment 6. Grow and develop during some part of their lives

Energy Energy- is the ability to do work Free energy- is the energy available to do work Ways to classify energy (active or not active) Kinetic- active energy, being used or expended Potential- stored energy

Types of Energy 1. Mechanical- energy of motion or stored motion 2. Chemical- energy stored in chemical bonds 3. Electromagnetic- energy found in electromagnetic waves (example: light, microwaves, electricity)

Nuclear energy- energy in the nucleus of the atom Heat energy- increases molecular motion of molecules

Energy converions 1st law of bioenergetics or (thermal dynamics)- energy cannot be created or destroyed just converted from one form to anther. Note: no energy conversion of free energy is 100% efficient

Example Eat a candy bar  running + unusable energy heat energy Eat a candy bar  running + unusable energy 180 Cal 60 Cal 120 Cal

2nd Law of Bioenergetics (thermal dynamics)- Systems tend to change in a way that increases the disorder, or entropy, of a system or the surroundings. In a closed system where energy cannot get in or out the amount of free energy will decrease. The clock is an example of a closed system

What is Entropy? Entropy- is the measure of disorder of a system Example: 1000  900 + 100  800 + 200 700 + 300  600 + 400 500 + 500  400 + 600  300 + 700  200 + 800  100 + 900  0 + 1000

Catabolic reactions Cellular respiration C6H12O6 + 6O2  6CO2 + 6H2O + ATP Exothermic or Exergonic Molecules are broken down Energy is released

Anabolic reaction Photosynthesis 6CO2 + 6H2O  C6H12O6 + 6O2 Endothermic or Endergonic Molecules are synthesized into polymers (larger molecules) Energy is required

The type of energy cells use ATP (Adenosine triphosphate) ATP is related to the nucleotide found in RNA ATP used to do cells work

ATP Generally drawn like this

ATP is used for Motion-muscles Nerve function Synthesizing other compounds It is the phosphate that has energy because of the negative charge

Cellular respiration A process of phosphoralating ADP to make ATP by oxidizing glucose Anabolic reaction ADP + P  ATP Catabolic reaction C6H12O6 + 6O2  6CO2 + 6H2O + ATP *overall this is considered to be a Catabolic rxn

Photosynthesis 6CO2 + 6H2O  C6H12O6 + 6O2 Glucose (C6H12O6 ) is made by photosynthesis Anabolic rxn 6CO2 + 6H2O  C6H12O6 + 6O2 *overall photosynthesis is an anabolic rxn

Energy flow through the ecosystem Ecosystem- all biotic and abiotic factors in a given area Biotic Factors- living organisms Examples: animals, plants, and decomposers Abiotic Factors- nonliving factors Examples: pH of soil, temperature, and rainfall

Autotrophs (producer) Take inorganic materials and convert them to high energy/organic compounds ; by photosynthesis or chemosynthesis EX: 6CO2 + 6H2O  C6H12O6 + 6O2 EX: producer/plants

Photo vs. Chemo Chemo- synthesis Photosynthesis 1. plant leaves take up energy from the sun 2. leaves take up CO2 from the atmosphere 3. photosynthesis occurring in the leaves 4. oxygen release through the stomates Chemo- synthesis 1.Hydrothermal fluid coming out of vents release hydrogen sulfide 2.Microbes living around the vents take up HS-, oxygen, and carbon dioxide 3.Mricobes get energy by breaking down compounds and converting to sugars 4.Microbes release sulfur and water

Heterotroph (consumer) Consume organic matter (high energy) to make their own food Types of Consumer Primary (herbivore)- consume plant matter Secondary (carnivore)- consume herbivores Tertiary (carnivore)- consume carnivores Decomposer- obtains energy from dead organisms

Energy Energy does not recycle like nutrients (carbon, nitrogen, water and phosphorus cycles) Because a certain percentage of free energy is converted to heat energy

Energy Pyramid Illustrates the energy flow from one trophic level to the next in an ecosystem Approximately 10% of energy can go from any one level to the next

Why is it a pyramid? No level completely consumes the preceding 2nd Law of thermodynamics Even eaten food is not all consumed (“stuff” comes out the other end)

Other ecological pyramids: Pyramid of biomass- the total mass of organisms decreases from one level to the next because there is less energy. Pyramid of numbers- from one trophic level to the next there is a decrease in the population because there is less energy and less matter at each level.

Food Chain- a series of organisms (3-5) through which energy is passed in a ecosystem

Food Web- shows a more complete energy flow through and ecosystem with interactions

Biosphere- the part of the earth that sustains life