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MISD Notes 6 Interdependence of Organisms. Nutrition and Energy Flow Two classes of organisms when it comes to energy flow Producers: Autotrophs: Organisms that use energy from the sun or energy stored in chemical compounds to make their own nutrients
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Nutrition and Energy Flow • Two classes of organisms when it comes to energy flow • Producers: Autotrophs: Organisms that use energy from the sun or energy stored in chemical compounds to make their own nutrients • Examples: Plants and some unicellular organisms • Consumers: Heterotrophs: Organisms that cannot make their own food and must feed on other organisms. • Herbivores: Feed directly on autotrophs (plants) • Carnivores: Feed on other heterotrophs (animals) • Scavenger: something that feeds on something that has already died. • Omnivores: Feed on both autotrophs (plants) and other hetertrophs (animals) • Decomposers: Break down and digest dead decaying material.
Nutrition and Energy Flow • Matter and energy Flow in an Ecosystem. • Food Chain: Simple model used by scientists to show nutrient and energy transfer in an ecosystem. • Uses arrows to indicate the direction of transfer. • Example: Insect Fish Bear • Most food chains have only three links and rarely more than five because energy is lost as heat in every exchange. • Trophic Level: Each organism in a chain that represents a feeding step. • Level 1: Autotroph • Level 2: first order heterotroph (herbivore) • Level 3: second order heterotroph (carnivores that feed on first order heterotrophs) • Level 4: Third order heterotroph (carnivore that feeds on a second order heterotroph) • Example Plant Insect Fish Eagle
Nutrition and Energy Flow • Not everything lines up in a perfect chain. A first order heterotroph may feed on several different plants and so on. This is why scientists use a Food Web. • Food Web: represents all the possible feeding relationships at each trophic level. • Ecological Pyramids: Used to show the energy flow through an ecosystem. • Energy decreases as you go up each level • The total energy transfer from one level to the next is about 10%. • Energy is lost for metabolism, growth, and as waste. • The only energy that is transferred to the next level is what was used for growth • This can also be translated into numbers of animals feeding at each level. Called a Pyramid of biomass.
Example of food web Taken from: http://faculty.abe.ufl.edu/~chyn/age2062/lect/lect_28/40_07.GIF .
Example of an Ecological PyramidTaken From: http://www.bio.miami.edu/dana/160/pyramid.gif
Example of an Ecological pyramid of biomassTaken From: http://www.science.org.au/nova/039/039img/039img.gif
Water cycle • Evaporation: Water changes to vapor and rises into the sky. • Condensation: The water vapor cools high in the atmosphere. The molecules move close together condensing into clouds. • Precipitation: The condensed water forms rain, snow, sleet, or hail and falls back to the Earth. • Collection: water collects in lakes, rivers, and the oceans where it again evaporates. • Transpiration: Water evaporates from the leaves of plants. • Water leaves animals through: • Respiration: animals exchange gases and release water as we breath • Urination: Water is expelled from animals during urination. • Sweat: The body uses water to cool the skin through evaporation.
Water cycleImage taken from:http://courseweb.unt.edu/rhondac/spring2006/webpages/Watercyclegraphic1.gif
Carbon Cycle • All life on Earth is based on Carbon • Carbon is found in proteins, carbohydrates, and fats. • Autotrophs (plants) use carbon dioxide and sunlight to make a carbon chain-Glucose (photosynthesis). • Autotrophs use these molecules for growth and energy. • Heterotrophs eat autotrophs and use the energy they have converted to chemical form sunlight. • Used for energy = Carbon Dioxide released • Used for growth = made into proteins, carbohydrates, and fats. • Things die and decay into soil. Bacteria release carbon back into the atmosphere as CO2
Carbon CycleImage taken from http://www.scienceclarified.com/images/uesc_02_img0109.jpg
Nitrogen Cycle • Nitrogen is found in the proteins that make up plants and animals. • It makes up 78% of the atmosphere but must be “fixed” to or converted to a usable form by lightning or bacteria. • This is released into the soil when organisms die. • This nitrogen cannot be used by plants in this form. • It is changed to ammonia(NH3) by fungi and bacteria. • Bacteria continue to convert it to nitrites (NO2) and then finally nitrates(No3). • Nitrates can be used by plants. • Plants (autotrophs) are eaten by animals (heterotrophs)
Nitrogen cycleImage taken from:http://www.kidsgeo.com/images/nitrogen-cycle.gif
Levels of organization Consumers 5th order heterotrophs: Hawk 4th order heterotrophs: Snake 3rd order heterotrophs: Mouse 2nd order heterotrophs: Preying Mantis 1st order heterotrophs: Cricket Autotrophs: Plants: Grass Producers