trophic levels trophic efficiency bioaccumulation
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Trophic Levels Trophic Efficiency Bioaccumulation. Seatwork. Read pages 24-26 and then answer the following questions. LEAVE SPACE after each answer. Define trophic level and give several examples. Define biomass. Define trophic efficiency Define bioaccumulation. Define biomagnification. - PowerPoint PPT PresentationTRANSCRIPT
Trophic LevelsTrophic EfficiencyBioaccumulation
Seatwork Read pages 24-26 and then answer the
following questions. LEAVE SPACE after each answer.
Define trophic level and give several examples.
Define biomass. Define trophic efficiency Define bioaccumulation. Define biomagnification.
A trophic level is a category of organisms that is defined by how the organisms gain their energy.
Examples: First trophic level = primary producers Second trophic level = primary consumers
(herbivores) Third trophic level = secondary consumers
Trophic Levels
Biomass is the total mass of living organisms in a defined group or area.
It includes living cells and tissues that have been assembled by organisms using solar energy.
Plant material is packed with chemical energy that has been converted from solar energy.
Animals indirectly rely on solar energy by eating plants or animals.
Biomass
Trophic efficiency is a measure of the amount of energy or biomass transferred from one trophic level to the next higher trophic level.
Trophic efficiencies are quite inefficient – only about 10%.
Organisms use much of the energy from the biomass they consume for life functions and wastes they produce
Trophic Efficiency
Herbivores don’t eat all of the plant
Not everything that is eaten is digested
Reasons for Biomass Decreases Between Trophic Levels
Energy is lost as heat by organisms Energy is used for life processes
Reasons for Energy Decrease between Trophic Levels:
Because of the inefficiencies of energy transfer among trophic levels, there are usually fewer carnivores than herbivores and fewer herbivores than plants
Relative Numbers at Trophic Levels
Bioaccumulation is a process in which materials, especially toxins, are ingested by an organism at a rate greater than they are eliminated.
Biomagnification is the increase in concentration of a toxin as it moves from one trophic level to the next.
Water Pollution and Bioaccumulation
Read pages 25-27 and then answer the following questions:
1. Explain how the use of DDT and PCB’s are example of bioaccumulation and biomagnification.
2. Review Questions 5 to 8 on page 27
Seatwork