1
1. Take in materials, convert into energy, and release waste 2. Chemical organization made of cells 3. Complex structural organization (orderly) 4. Contain DNA-instructions for maintaining everything 5. Sense and react to changes in environment 6. Grow and Develop 7. Reproduce (sexually or asexually) 8. Communicate 9. Move under THEIR own power 2
The study of energy and energy flow in living systems (environments) and the organisms (plants and animals) that utilize them 3
All things do what they do b/c of some source of energy. All organisms obtain energy to Carry out chemical reactions (break down macromolecules and then to build complex molecules) Move (muscle contraction, exercise) Transport nutrients to build complex molecules for cells 4
Chemical Energy is the energy stored in organic molecules Free energy is the energy available to do work (usable energy) 5
6
Heterotrophs: get energy from other organisms (living or dead) ex: fungus, animals Autotrophs: get energy and nutrients from the sun or chemicals. 1. Photoautotroph: Capture energy from the sun to make organic compounds through photosynthesis. Ex: plants 2. Chemoautotroph: Capture free energy from chemicals to make organic compounds through chemosynthesis. Ex: bacteria 7
8
Heterotrophs: obtain energy and nutrients from other organisms. 1. Carnivore: Meat eater 2. Herbivore: Plant eater 3. Omnivore: Meat and Plant eater 9
Autotrophs and Heterotrophs carry out chemical reactions that release the chemical energy in organic compounds into free energy for maintenance, growth, reproduction, etc in a process called Cellular Respiration 10
11
Energy flows from the environment through producers to consumers and finally to decomposers. 12
Producers: Produce food other organisms use through photosynthesis Consumers: Consume plants and other organisms for food Decomposers: Break down and use dead plants and animals for food (ex: bacteria, fungi, other heterotrophs) 13
14
15
Food chains describe the eating relationships or transfer of energy in one direction between organisms in an ecosystem In this simple food chain, the grass generates energy it gathers from the sun through photosynthesis, which is then passed along to the grasshopper, the frog, the snake, and finally the hawk. 16
17
Food webs show how energy and nutrients flow throughout overlapping food chains of an ecosystem. The arrow points to whom is getting the energy/nutrients 18
Abiotic (non-living) factors Biotic (living) factors These factors make up every ecosystem. Habitats (where particular organisms live) make up each ecosystem All ecosystems make up the biosphere deserts, coral reefs, tundra 19
20
Abiotic factors- the nonliving parts of an organism s environment. Examples include air currents, temperature, moisture, light, and soil. Abiotic factors affect an organism s life. 21
Biotic factors- all the living organisms that inhabit an environment. Examples include Bear, fish, insects, bacteria All organisms depend on others directly or indirectly for food, shelter, reproduction, or protection. 22
First Law of Thermodynamics: Energy cannot be created or destroyed but can only change form. Aka Law of Conservation of Energy total amount of energy in the universe is constant and exists in many forms Burning log (nonliving)- Heat energy is released Chemical energy produced (ash & smoke) Wolf eats deer (living)- Heat energy is released Digests food so free energy is released in cells used for work (muscle contraction, growth, repair). Organisms cannot create their own energy they must get it from an outside source! 23
24
25
Systems change in a way to increase disorder (entropy) of the system & its surroundings. The direction of energy flow is from high to low quality forms. Each conversion results in the production of energy (as HEAT which is unavailable for work). The Second Law of Thermodynamics is the Law of Increasing Entropy. This law states that the universe is always moving toward a greater state of disorder, or entropy. 26
Anything that happens spontaneously, that is, without an input of energy, will result in molecules being more disorganized, more random, more mixed together, and more spread out. The law of increasing entropy also explains why houses don t spontaneously assemble from a pile of wood on the lawn, spills don t mop themselves up, and dust doesn t gather itself into a neat pile, ready to be swept up. Such processes that result in an increase of organization (that is, a decrease in entropy) require energy input and are not spontaneous. 27
28
Total energy of the universe remains the same (1 st law). It is, however randomly dispersed as heat energyan unusable form of energy for organisms which increases the entropy of the universe (2 nd law) 29
-Order is important. Our bodies represent a high degree of order: atoms and molecules are meticulously organized into a complex system how does this happen? ENERGY from cellular respiration. -Seed are stored energy & nutrients, becomes an embryo, then a more complex organized tree how does this happen? ENERGY from the sun 30
31
Unusable Randomly dispersed so increases the entropy of the universe Useable Available to do work 32
There is a mathematical equation that can help us determine if a chemical reaction occurs on its own or if it needs the input of energy to happen. This equation was derived by Williard Gibbs in 1878. The equation is called Gibbs Free Energy Equation. 33
34
Free energy = available energy Enthalpy (H) = total energy of a system ball rolling down hill, glucose molecule Entropy (S) = disorder of a system Diffusion, messy room Temperature (T) = in Kelvin C+273 Cherry bomb will not explode unless temp is increased more spontaneous with increase in temp All these factors can affect the spontenaity of a chemical reaction 35
S is Entropy. In all of the mathematical problems that we do related to Gibbs free energy equation you will always be given the values of S and H and will need to convert T from degrees C. You will then come up with a value for change in free energy which will help you predict if equations will happen on their own or need outside energy put in to occur. 36
Gibbs Free Energy (G) - The energy associated with a chemical reaction that can be used to do work. The free energy of a system is the sum of its enthalpy (H) plus the product of the temperature (Kelvin) and the entropy (S) of the system: G < 0 = spontanteous, exergonic reaction?? G > 0 = not spontaneous, endergonic?? G = 0 = equilibrium 37
38
39
40
The energy in a molecule available to do work is called Gibbs free energy (G). More important for us, the change in this free energy during a chemical reaction is called ΔG which can be positive or negative. What are the reactants and the products of photosynthesis & cell resp. Is each process endergonic or exergonic and what sign would you expect ΔG to have and why? Photosynthesis: Light energy + 6 CO 2 + 6 H 2 O ----> C 6 H 12 O 6 + 6 O 2 Cell Respiration: C 6 H 12 O 6 + 6 O 2 ----> 6 CO 2 + 6 H 2 O + 32 ATP 41