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The Biosphere Chapter 3
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3.1Levels Within Levels An ecosystem is a collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment. Within an ecosystem, there are several levels of organization. Your school and its grounds are similar to an ecosystem.
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In Your Notebook 1. What living things are found in and around your school? 2. What nonliving things are found in your school? 3. Into what large groups are the students in your school divided? 4. Into what smaller groups are these large groups divided?
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What Is Ecology? The scientific study of interactions among organisms and between organisms and their physical environment. How do cats live with dogs? Why are some species protected? How have humans changed the landscape and atmosphere here on earth?
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Levels of Organization
Look on pages 64 & 65 in your book In Your Notebook Draw a circle and label it βMeβ Draw five concentric circles and label each of them with the appropriate level of organization. Describe your population, community, etc.
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Biotic and Abiotic Factors
Environment All conditions surrounding an organism Biotic Factors Any living part of the environment Abiotic Factors Any nonliving part of the environment Sunlight, heat, precipitation, humidity, wind or water currents, soil type
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Biotic and Abiotic Factors
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In Your Notebook Read Page 67
In your own words, explain the difference between biotic and abiotic factors. Give three examples of each.
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Ecological Methods Observation Experimentation Modeling
What lives here? How does an animal protect its young? Experimentation Artificial environment Greenhouse Modeling Global warming Solar system
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In Your Notebook Give an example of two objects or activities in your life that are interdependent. Explain your choice. Suppose you want to know if the water in a certain stream is safe to drink. Which ecological method(s) would you use in your investigation? Explain your reasoning.
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3.2 Producers and Consumers
All living things need energy. Some organisms can make their own energy from inorganic (nonliving) things in their environment, but other organisms need to consume other living things in order to get energy. The ways in which an organism obtains energy define its role in its ecosystemβ some organisms rely on others for energy, while others compete with each to obtain energy. Indeed, the need for energy drives many of the interactions that occur within ecosystems.
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In Your Notebook 1. List five activities that you do every day that require energy. 2. How do you get the energy that your body needs to carry out its normal functions? 3. What might happen if you didnβt get enough energy for your body to carry out its normal functions? What might happen if you were not using all the energy that you were taking in?
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Primary Producers The first producers of energy-rich compounds that are later used by other organisms. AKA β Autotrophs Make their own food Plants, Algae and some bacteria
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Primary Producers Photosynthesis Chemosynthesis
Using light energy from the sun to convert carbon dioxide and water into carbohydrates Chemosynthesis Use chemical energy to produce carbohydrates Usually found in deepest part of ocean
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In Your Notebook In your own words, explain two differences and two similarities between photosynthetic and chemosynthetic producers.
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Consumers Organisms that rely on other organisms for energy and nutrients. AKA-Heterotrophs Must get energy from other organisms Classified by the way they get their food Carnivores Scavengers Decomposers Herbivores Omnivores Detritivores
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In Your Notebook How do producers make energy-rich compounds?
How do consumers get the energy they need for life processes? What are some different categories of consumers?
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3.3 Pass It Along Energy flows in one direction through an ecosystem, from the sun or inorganic compounds to producers (organisms that can make their own food) through various levels to consumers (organisms that rely on other organisms for food). Your body gets the energy and materials it needs for growth and repair from the foods you eat.
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In Your Notebook 1. Make a list of five foods that you like to eat. Indicate whether the food comes from a plant (producer) or an animal (consumer). 2. Like many birds, chickens eat grains, which are seeds. Where do seeds come from? 3. Meat comes from beef cattle. What do cattle eat? 4. Construct a diagram showing how one of your favorite foods obtains its energy. Include as many levels as you can.
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Food Chains and Food Webs
What happens to energy stored in body tissues when one organism eats another? Eaten Eater How does energy flow through ecosystems? Energy flows in a one way stream, from primary producers to various consumers.
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Food Chains and Food Webs
A series of steps in which organisms transfer energy by eating and being eaten. Vary in length Always start with primary producer
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Food Chains and Food Webs
Most ecosystems more complicated and donβt have single simple chain Food Web Network of feeding interactions
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Food Chains and Food Web
Decomposers and Detritivores Most producers die without being eaten Decomposers convert the dead material to detritus This detritus is then eaten by detritivores Decomposition process also releases nutrients that get used by primary producers
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In Your Notebook Explain how food chains and food webs are related
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Food Webs and Disturbance
What happens in this food web if the population of krill declines?
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Trophic Levels and Ecological Pyramids
A step in the food chain Primary producers are always the first step Ecological Pyramid Shows the relative amount of energy or matter contained in each level Three types Pyramids of energy Pyramids of biomass Pyramids of numbers
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Pyramids of Energy Shows the relative amount of energy available at each trophic level of the food chain or food web How does the amount of energy at each level limit the number of organisms that can live there?
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Pyramids of Biomass and Numbers
Shows the relative amount of living organic matter Numbers Shows the relative number of individual organisms at each trophic level
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In Your Notebook Write a creative story about the organisms that live and interact in a fictitious ecosystem. Another student is going to read your story and will have to construct a food web for this ecosystem from the details that you include.
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3.4 Cycles of Matter Living organisms are composed of mostly oxygen, carbon, hydrogen and nitrogen. Throw in sulfur and phosphorus and you have all nutrients necessary to live. But organisms canβt make these elements, so where do they come from?
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Recycling in the Biosphere
Energy flows in one direction Matter is recycled within and between organisms Biogeochemical cycle Matter is never created or destroyed It just changes forms
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Biogeochemical Cycles
Biological Processes All activities performed by living things Geological Processes Volcanoes, breakdown of rock, earthquakes Chemical and Physical Processes Clouds, precipitation, lightning, running water Human Activity Mining, burning of fossil fuels, deforestation
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The Water Cycle
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In Your Notebook Describe how each of the following terms relates to the water cycle. Evaporation Transpiration Precipitation Runoff
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The Carbon Cycle
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In Your Notebook Read page 82
Describe one biological, one geological, one chemical and one human activity that is involved in the carbon cycle. Hint: Look at the color coded key that goes with Figure 3-17
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The Nitrogen Cycle Nitrogen Fixation Denitrification
Bacteria convert nitrogen gas into ammonia Denitrification Conversion of nitrates into nitrogen gas which is then released into the atmosphere
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The Phosphorus Cycle Vital part of DNA and RNA Not found in atmosphere
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Nutrient Limitation If ample sunlight and water are available, the primary productivity of an ecosystem may be limited by the availability of nutrients. If your recipe calls for 2 eggs to make 24 cookies, and you have plenty of flour, sugar, etc., how many cookies can you make if you have 1 egg?, 4 eggs?, 5 eggs? Limiting Nutrient The nutrient that runs out first
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Nutrient Limitation Soil Aquatic Ecosystems
Farmers use fertilizers with large amounts of nitrogen, phosphorus and potassium Carbon not necessary, plants get it from the atmosphere Aquatic Ecosystems Ocean usually limited by nitrogen Freshwater usually limited by phosphorus Gets out of balance when runoff from farm fields gets into water supply
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In Your Notebook How does the matter that flows through an ecosystem differ from the way that energy flows? Explain how a nutrient can be a limiting factor in an ecosystem.
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