All organisms need energy to carry out the activities of life such as moving, feeding, reproducing, and growing.

Transcription

1 Mantis Shrimp ECOSYSTEMS UNIT LESSON TWO Lesson Two: Energy Flow All organisms need energy to carry out the activities of life such as moving, feeding, reproducing, and growing. Only plants are able to take energy from the sun and use it to drive their activities. Most organisms cannot take the energy from the sun and use it directly for their own purposes. 1

2 Lesson Two: Energy Flow Instead, they eat other organisms to obtain their. energy Since organisms only eat certain other types of organisms, the trail of the energy can be traced as it flows along from organism to organism. Lesson Two: Energy Flow Outcomes After completing this lesson you will be able to: Describe the roles of, herbivores carnivores and omnivores Explain the difference between a food chain and a food web Draw a food web found in a local ecosystem Describe how energy flows through an ecosystem 2

3 Lesson Two: Energy Flow Key words carnivore ecological pyramid food chain food web herbivore omnivore primary consumer pyramid of energy scavenger secondary consumer tertiary consumer trophic level Lesson Two: What s the Big Idea Right now, even sitting there at your desk, you are using energy. Your heart is pumping, your diaphragm muscle is flexing to help you breathe, even your brain reading these words is using energy. Where did you get that energy? Think about your recent meals. If you ate an apple, that apple had energy in it that it got from somewhere. Every living thing requires energy to live. This lesson is about the movement of that energy throughout an ecosystem. 3

4 Lesson Two: Food Chains Since all living things require energy to live, the ultimate source of that energy is the. sun Producers such as plants and algae capture the sun s energy and transform it into organic compounds. These compounds are used to build plant parts such as leaves and flowers, or store extra energy in roots and seeds. Lesson Two: Food Chains consumers Unlike producers, are unable to directly transform sunlight into organic compounds. Primary consumers (also called ) herbivores feed directly on plants. Examples of herbivores include moose, cattle, grasshoppers, rabbits and aphids. Secondary consumers feed on primary consumers, and tertiary consumers feed on secondary consumers. These higher-level consumers are also known as. carnivores Examples of carnivores include wolves, northern pike, eagles, polar bears, ladybugs and snapping turtles. 4

5 Lesson Two: Food Chains Scavengers are carnivores that feed on dead animals. Examples of scavengers include blowflies, turkey vultures, eagles, seagulls and ravens. Where do we humans fit because many of us eat both plant and animals? We, along with black bears and red-wing blackbirds are omnivores because we feed on both producers and. consumers Lesson Two: Food Chains Each step in this series of feeding relationships is known as a trophic. level Producers and consumers are linked together in food, chains a sequence of organisms through which energy is passed. 5

6 Lesson Two: Food Chains Here is an example of a food chain in the Lake Winnipeg ecosystem consisting of four trophic levels: Lesson Two: Food Webs Because animals typically feed on more than one type of organism, food chains become connected in a complex relationship known as a. food web The carnivore at the top of the food chain/web is called a top carnivore. 6

7 Lesson Two: Food Webs The diagram shows the food web of the Lake Winnipeg ecosystem. 7

8 Lesson Two: Food Webs The arrows show how the sun s energy flows through an ecosystem from the sun, to, producers to, consumers and to. decomposers Because plants and animals die at all points in food chains, decomposers are found at all trophic levels in ecosystems. Trophic Levels in Food Chains/Web Lesson Two: Ecological Pyramids Ecologists use ecological pyramids to describe the energy flow among the trophic levels. You can visualize the total amount of incoming energy at each level in an ecosystem as a pyramid of. energy The area at the bottom of the energy pyramid represents the greatest amount of energy in an ecosystem. As the energy passes from producers to consumers, less is available each successive trophic level. 8

9 Lesson Two: Ecological Pyramids All the energy originates in the. sun Only 10% of the energy is passed on from one trophic level to another. This is because all of the energy that an organism takes in is not transformed into food. Energy is used by the organism for a variety of life processes such as breathing, transporting materials, movement, reproduction, and so on. The 10 Percent Rule 9

10 Lesson Two: Ecological Pyramids Only a portion of the energy used goes into building organic compounds. As a result, about 10% of the energy taken in at one trophic level is passed on to the next level. Less and less energy is available to organisms higher up the food chain. This explains why there are seldom more than four or five levels in a food chain. trophic Summary Food chains consist of producers and, consumers which are connected into food. webs Energy flows through ecosystems from one trophic level to the next. 10

11 Lesson Two Exercise #2 Questions 1-3 ECOSYSTEMS UNIT LESSON THREE 11

12 Lesson Three: Carbon & Oxygen Cycle While energy flows in a one-way direction through an ecosystem, nutrients are recycled over and over again. Biogeochemical cycles are the processes by which nutrients move through organisms and the environment. Lesson Three: Carbon & Oxygen Cycle You may be familiar with the water cycle in which water moves from the Earth s atmosphere to the surface ( ), precipitation and back to the atmosphere again ( ). condensation Other important nutrients that are recycled are, carbon oxygen and. nitrogen This lesson will focus on the carbon and oxygen cycle. 12

13 Lesson Three: Carbon & Oxygen Cycle Outcomes After completing this lesson you will be able to: carbon Explain how is cycled through an ecosystem oxygen Explain how is cycled through an ecosystem Create a diagram of how the carbon and oxygen cycle works Lesson Three: Carbon & Oxygen Cycle Key Words biogeochemical cycle carbon cycle carbon sink cellular respiration glucose oxygen cycle 13

14 Lesson Three: Carbon Cycle The process by which carbon moves through an ecosystem is called the. Carbon cycle Producers such as green plants and algae take in a carbon-containing nutrient known as carbon dioxide from the atmosphere. Lesson Three: Carbon Cycle CO 2 The chemical formula of carbon dioxide is. This process is called. photosynthesis 14

15 Lesson Three: Carbon Cycle The chemical formula for photosynthesis is: photosynthesis During, the energy of the sun is used to convert carbon dioxide into, glucose a type of organic compound. Lesson Three: Carbon Cycle Plants then change glucose into other types of carbon compounds. The chemical formula for glucose is. When animals eat plants and algae, the carbon compounds are converted into glucose. The glucose is then converted into carbon dioxide and energy in a process known as. cellular C 6 H 12 O 6 respiration 15

16 Lesson Three: Carbon Cycle The chemical formula for cellular respiration is: The energy is used by organisms for growth, movement, reproduction, excreting wastes, digesting food, and so on. The carbon dioxide is released into the atmosphere, and the cycle continues. 16

17 Lesson Three: Carbon Cycle Areas that naturally or artificially store large quantities of carbon containing compounds are known as. carbon sinks forests Examples of natural carbon sinks are, and. oceans Artificial carbon sinks would include landfills and. and carbon capture storage facilities 17

18 Lesson Three: Oxygen Cycle oxygen cycle The, which moves oxygen through an ecosystem, is closely linked to the carbon cycle. Plants use water during photosynthesis and release oxygen gas into the atmosphere. O 2 The chemical formula for oxygen gas is. Lesson Three: Oxygen Cycle Organisms then use the oxygen gas during cellular respiration and release water into the atmosphere. The cycle continues as plants produce oxygen during photosynthesis, which is then used by organisms in cellular respiration. 18

19 Lesson Three In this lesson you have studied the cycle, the cycle. oxygen These biogeochemical cycles are the means by which nutrients move through organisms and the environment. These cycles allow to be recycled over and over again. In the next lesson we will examine how ecosystems are affected when nutrient cycles are. disturbed carbon carbon + oxygen Lesson Three Exercise #3 Questions