Please take out your Chapter 3 Reading Assignment (Module 6 is due) APES 10/2 Please take out your Chapter 3 Reading Assignment (Module 6 is due)

Unit One Test Results Multiple Choice Short Answer A = 24.5-27 B = 21.5-24 C = 19-21 D = 16-18.5 Class Average = 21.07, 21.79 Retakes for scores of 18 and below are available this week during Power Hour Class Average = 7.2, 7.8 Retakes for scores of 6.5 and below Retakes can improve your score up to a 70% You can take one or both sections

Check your work! Module 6: 1. A 2. D 3. A 4. C 5. B 6. E GPP – Respiration = NPP

Chapter 3 Quality Check 6, 11, 12b. WRITE THEM DOWN WORD-FOR-WORD. NO CHANGES!

EcoColumns Time Today: Finish construction Rinse water through the column twice Add leaf litter, bugs, seeds to the top

Food Webs and Energy

Levels of Organization Biosphere Biomes Ecosystems Communities Populations Individuals Cells/ Tissues Living things can be studied at many levels: In Ecology, we will study everything above individuals

Levels of Organization Biosphere: Our earth! Biome: areas of biosphere that have similar climate, plants, and animals Ecosystem: collection of living and non-living things that make up an environment Desert Biome Old Growth Forest Ecosystem Biosphere

Levels of Organization Community: populations of different species living together (ex: humans and bacteria living together) Population: group of one species living together Species: a group of organisms that can only breed with each other Population of prairie dogs (a species) Community of macaws, grasses, insects…

Energy Flow Through Ecosystems Section 3.2

What do Ecosystems Need? For ecosystems to thrive, its members need energy and matter Matter = liquid, solid, and gas ‘stuff’ Energy moves in a one-way flow, while matter recycles. Today’s focus = energy

Energy for Ecosystems The sun provides the initial energy for ecosystems Plants harvest sunlight and turn light energy into chemical energy (glucose) This is called photosynthesis CO2 + H2O + light glucose + O2 In an ecosystem, we call plants producers

Energy for Ecosystems Chemical energy (glucose) stored in plants is passed on to herbivores, which eat the plants Chemical energy in herbivores (protein, fat, sugar) is passed on to carnivores, which eat the herbivores This forms a food chain/web.

ENERGY ALWAYS FLOWS THE SAME WAY THROUGH AN ECOSYSTEM: Sun Producers Consumers Energy does not recycle. It is lost as heat when organisms burn it off!

How is the chemical energy used? Plants AND consumers use the energy in sugar for cellular respiration. Glucose + O2 CO2 + H2O + ATP It’s converted to a smaller, more useable molecule called ATP, which is converted to kinetic energy.

Players in the Food Web Plants are called producers, and also autotrophs Autotroph = makes own food using sunlight First level consumers eat producers Second level consumers eat first level consumers, and so on Consumers are also called heterotrophs (get food/energy from outside source)

Practice Time Watch the Planet Earth video clip Make a food web on your whiteboard Label producers (P), 1st, 2nd, 3rd level consumers, detritivores, decomposers (inferred) Put a star next to heterotrophs

Other Players Detritivores (mites, snails, and worms) feed on dead matter Decomposers (bacteria and fungi) break down dead matter

Trophic Levels Each step along a food chain or web is called a trophic level Producers are the first trophic level Consumers make up the second, third, and higher trophic levels Also called primary, secondary, tertiary consumers

Energy Pyramids The energy that producers and consumers can possibly make and pass on can be represented in an energy pyramid Because producers photosynthesize and are numerous, they are on the bottom of the pyramid

Pyramid of Energy Example -Students jot down this pyramid of energy in notes (don’t need pictures). Important to include trophic level labels (producer, primary consumers, etc.) -The “J” stands for joules. Joules are a measure of energy. Calories are another measure of energy. -Ask students: Quantitatively, what do you notice about how the amount of energy decreases each step through the food chain? -Notice that each trophic level generally gets ~10% of energy from previous trophic level. This is called the 10% rule.

Measures of Energy in Ecosystems Gross Primary Productivity (GPP) = total solar energy captured by plants (ONLY ABOUT 1%) Net Primary Productivity (NPP) = total energy captured minus the energy used by producers for their own respiration (what’s left over for consumers!) NPP = GPP – Respiration by Producers

Practice Problem A forest has an NPP of 1.4 kg C/m2/year and the rate of cellular respiration is 2.4 kg C/m2/year. What is the GPP? NPP = GPP – Respiration 1.4 = GPP – 2.4 GPP = 1.4 + 2.4 = 3.8 kilograms of Carbon per square meter per year

Biomes Differ in NPP

Ecological Efficiency Proportion of energy that is passed between trophic levels, after cellular respiration 10% on average! -Students copy this definition -Ask students to think: why do you think this happens? Think of the game from yesterday. (go to next slide as you talk about this)

10% rule... 10% 90% lost as heat

How much energy is at each level? 1000 Cal ? Cal

How much energy is at each level? 9 Cal as heat 1000 Cal 100 Cal 10 Cal 1 Cal 90 Cal as heat 900 Cal as heat

Pyramid of Biomass At which level is the most biomass located? Biomass= total mass of living matter in an area At which level is the most biomass located?

Pyramid of Biomass Same as pyramid of energy 1000 grams 600 grams 200 grams 100 grams Same as pyramid of energy More mass in bottom trophic levels

Due Next Time Wetlands FRQ