FOOD CHAINS AND WEBS Do Now: Draw a food chain that includes the following organisms: Do Now: Draw a food chain that includes the following organisms: grasshopper grasshopper mouse mouse grass grass owl owl Now label the organisms as producers, consumers (which type?), or decomposers Now label the organisms as producers, consumers (which type?), or decomposers PRODUCER CONSUMER (HERBIVORE) CONSUMER (CARNIVORE)
FOOD CHAINS A food chain shows the path of energy from one organism to the next energy flows from producers to consumers arrows point to who is eating (plant is eaten by herbivore) Usually decomposers are left out
FOOD WEBS A food web shows all feeding relationships in an ecosystem (made of many food chains) A food web shows all feeding relationships in an ecosystem (made of many food chains)
FOOD WEBS Typically, food webs go like this: PRODUCER CONSUMER (HERBIVORE) CONSUMER (CARNIVORE) CONSUMER (OMNIVORE) DECOMPOSER remember: decomposers receive energy from all other organisms in an ecosystem remember: decomposers receive energy from all other organisms in an ecosystem
Energy Flow through Ecosystems
Do Now: What does the suffix “troph” mean? What do you think trophic level is?
TARGET GOAL: SWBAT explain how organisms attain energy needed for survival and how energy is lost in ecosystems.
If you were to run a marathon, which food would you choose for the most energy?
ENERGY ENTERS ECOSYTEM AAll energy in ecosystem comes from the sun FFirst law of Thermodynamics: Energy cannot be created or destroyed (but it can be transformed into stored energy & heat)
ENERGY LEAVES ECOSYSTEM Second law of thermodynamics: Energy is transformed, some lost In ecosystems, when energy is transformed, some energy is lost as HEAT
ENERGY PATHS 3 ways to illustrate energy flow 1. Food Chain: Single path 2. Food Web: many paths 3. Food Pyramid
What do all the pictures have in common? How are they different?
Why are there more organisms at the base trophic level and less organisms as you travel up the pyramid?
FOOD CHAINS/WEBS & ENERGY PYRAMIDS Food chains/webs can be written as a pyramid: Producers form the base of the pyramid Consumers form the upper layers Consumers form the upper layers
What does an Energy Pyramid show? Shows how many Joules of energy each level of organisms get. Numbers decrease as you go up in the pyramid. Why? Because each level of organisms gets less energy than the last – 90% of energy is lost as heat in each level.
ENERGY PYRAMIDS A level of the energy pyramid is called a TROPHIC LEVEL Each trophic level represents the energy for those organisms Top Consumer Energy stored by Secondary Consumers Energy stored by Primary Consumers ENERGY STORED BY PRODUCERS The energy pyramid shows energy flow in an ecosystem:
Question Time! Which organisms are at the bottom of the pyramid?
Question Time! True or False: High level consumers get the most energy because they are at the top of the pyramid.
TROPHIC LEVELS Energy is lost with each trophic level ~90% is released to the environment as heat ~10% of the energy is used Only about 10% of the energy from one level is passed on to the next level
Your Assignment: Draw an Energy Pyramid. Label all the trophic levels with the type of organism (including type of consumer) and write examples of organisms you would find in that level. On the side of you pyramid, next to each trophic level, write how much energy each level receives- either in Joules or in percent %.
Exit Ticket If 100% of the energy is available at the first trophic level, what percentages of the energy are available at the second and third trophic levels?
Exit Ticket If 100% of the energy is available at the first trophic level, what percentages of the energy are available at the second and third trophic levels? 100% 10% 1%
Construct an energy pyramid. Color each trophic level a different color, label each trophic level. Drawing pictures and making it neat will add extra points to your project.