Science 10 FEEDING RELATIONSHIPS

/food/foodweb2.html

IMPORTANT TERMINOLOGY

SOURCE OF ENERGY FOR ALL ECOSYSTEMS IS THE SUN

 Photosynthesis is the process by which plants convert energy from sun to usable energy for humans  Human survival depends on the stored energy in agricultural ecosystems

Animals that get energy from eating plants Possess special digestive systems for digesting all kinds of plants Need a lot of energy to stay alive May eat all day long  Possess special digestive systems for digesting all kinds of plants  Need a lot of energy to stay alive  May eat all day long HERBIVORES

Animal that eats either other animals or plants  Some will hunt and others will scavenge for dead matter or eggs of other animals Generally eat only the fruits and vegetable of fruit-bearing plants OMNIVORES

Generally eat herbivores, but will also eat omnivores  Require large amounts of energy in order to hunt and kill  The bigger the carnivore, the more it has to eat. Important to the ecosystem because they keep other species from becoming overpopulated. CARNIVORES

DECOMPOSERS

 Important terms:  Trophic levels  Detrivores  Decomposers  Pyramid of Numbers  Pyramid of Biomass  Pyramid of Energy Flow SECTION 1.2 FEEDING LEVELS

 First trophic level – always plants  Second trophic level – primary consumers  Third trophic level – secondary consumers FEEDING LEVELS

 Energy flows through the food chain but only about 10% of the energy is passed on from one trophic level to the next.  Ex: Plant has 100kJ, caterpillar uses 10% for life processes, 90% is lost as heat or waste

 Food chains are useful for describing basic feeding relationships among organisms  Pyramids illustrate different feeding relationships  visual comparisons among organisms at different trophic levels within the same pyramid and between pyramids  Pyramid of Numbers  Pyramid of Biomass  Pyramid of Energy ENVIRONMENTAL PYRAMIDS

 Shows the numbers of organisms that are required to feed the next trophic level.  The greatest number of organisms is in the first trophic level, least number on top of the trophic level PYRAMID OF NUMBERS

 Shows the relative mass of the organisms at each trophic level  Shows the energy available in each trophic level  More useful than pyramid of numbers because it takes into account the size of the organism PYRAMID OF BIOMASS

 Shows the amount of nutrient energy at each trophic level (difficult to measure  Shows how the energy available at each trophic level is greatest at the bottom of the food chain and least at the top  Pyramid of energy is always upright and cannot be inverted, the other pyramids can be PYRAMID OF ENERGY FLOW

PYRAMID OF ENERGY



 Organisms that receive energy from dead plant and animal material  Make up majority of food chains  Scavengers eat the remaining energy in large dead organisms  Ex: Vultures eat the carcasses of dead animals DECOMPOSER FOOD CHAINS

 Decomposers – types of organisms that break down cells to extract remaining energy  Ex: fungi and bacteria

SYMBIOSIS  Mutualism: 2 species benefit from the relationship  Example: algae lives in coral. The algae gives the coral energy and the coral gives the algae protection and carbon dioxide.  Commensalism: 1 species benefits while the other is unaffected. (shark and remora)  Parasitism: when an organism benefits at the expense of a different organism. (human and tapeworm)

 %20%20understanding_the_environment.htm %20%20understanding_the_environment.htm  s_by_Unit/Unit_4.htm s_by_Unit/Unit_4.htm REFERENCES/RESOURCES