Sazzy Gourley and Ariana Lutterman Chapter 4: Ecosystems and Energy

1: What is Energy? Energy: capacity or ability to do work Six forms: 1. Chemical 2. Radiant/solar 3. Heat 4. Mechanical 5. Nuclear 6. Electrical Can be potential or kinetic

2: Thermodynamics Thermodynamics: the study of energy and its transformations Three types of systems: Closed: matter can’t move in and out, energy can Open: matter and energy move in and out Isolated: nothing in and out (not on earth)

Laws of Thermodynamics 1 st law: energy cannot be created or destroyed, but it can be transformed Example: Light energy to heat energy 2 nd law: when energy is transformed, some energy is lost to the environment as heat The amount of biologically usable energy decreases over time Entropy: measure of disorder or randomness Increases over time Disorganized, unusable energy has high entropy

3: Photosynthesis and Cellular Respiration Photosynthesis: biological process in which light energy from the sun is captured and transformed into chemical energy of carbohydrate molecules 6CO H 2 O + radiant energy  C 6 H 12 O 6 + 6H 2 O + 6O 2 Cellular respiration: process in which the energy of organic molecules is released within cells of ALL organisms C 6 H 12 O 6 + 6H 2 O + 6O 2  6CO H 2 O + radiant energy

4: Chapter Vocabulary Energy Flow: movement of energy in ONE direction Arrow = flow, box = storage Producer/Autotroph: uses sun directly for energy (plants) Consumer/Heterotroph: depend on other organisms for energy Decomposer/Saprotroph: break down dead organic material and absorb nutrients for energy

Detritus: currently decomposing organic matter Detritivore: eats detritus Trophic level: energy level in a food chain (e.g. primary, secondary, tertiary) Primary consumer: eats producer Secondary consumer: eats primary consumer Tertiary consumer: eats secondary consumer

5: Ecological Pyramids Pyramid of energy: total amount of energy stored at each trophic level Law of 10%: only ten percent of energy in each trophic level moves to form new biomass No exceptions

Pyramid of Biomass: dry weight of organic matter in each trophic level Represents chemical energy stored in organic matter of a trophic level Extrapolate to entire trophic level from quantitative samples (e.g. mark-recapture) Exception: big whales, small krill, big algae whales algae krill

Pyramid of Numbers: total number of organisms at each trophic level Decreases as you go up Exception: one tree can feed multiple organisms insects tree birds

6: Productivity Gross Primary Productivity (GPP): how productive are the plants Net Primary Productivity: what’s available to primary consumers Net Primary Productivity = Gross Primary Productivity – Plant Respiration NPP = GPP - R P

Secondary Productivity: rate of biomass accumulation by heterotrophs (i.e. growth) NPP = GPP – R P GSP = NPP – Not Used – Fecal Waste (assimilated) NSP = GSP – R C (energy gained at very end) NEP = NPP – R C or GPP – R TOT TLE (Trophic level efficiency) = Production/Consumption

7: Productivity Cleared Up GPP RPRP NPP Ingested Not Used GSP (assimilated) NSP (growth and reproduction) Waste RCRC