Trophic Structure

THE TROPHIC STRUCTURE : 

THE TROPHIC STRUCTURE By: Shirley D. Regalado

General Objectives : 

General Objectives Categorize the biotic components of the ecosystem; Appreciate the importance of biotic components in the ecosystem; Provide a better understanding about the complexity of the food web; Recognize the difference among the three ecological pyramids.

Key Ideas : 

Key Ideas Trophic level of the ecosystem includes the producers, primary consumers, secondary consumers, tertiary consumers, and the decomposers. Food Chain is the transfer of matter and energy from one organism to another organism as one individual eats another or dies and decomposes;while food web is a complex pattern of interconnected food chains.

Key Ideas : 

Key Ideas The energy decreases as it transfer from one trophic level to the next due to the inability of the consumers to fully assimilate the food they eat, and the dissipation of energy into the atmosphere as heat.

Lesson I: Trophic Relationships in the Ecosystem : 

Lesson I: Trophic Relationships in the Ecosystem Specific Objectives: Identify the trophic levels of the ecosystem based on their food source; Discuss the role of producers, consumers, and decomposers in the ecosystem; Distinguish between a food chain and a food web; Explain pyramid of energy, pyramid of numbers, and pyramid of biomass; Describe how human activities interfere the ecosystem.

Motivational Activity: “Brainstorming” : 

Motivational Activity: “Brainstorming” Different kinds of seeds will be shown to the class. Questions: Where did these seeds come from? Suppose that these seeds fall on the ground and is eaten by an animal. What type of animal might eat it? What type of animal might eat the animal that ate the seed?

Questions (continued) : 

Questions (continued) 4. What type of animal might eat this animal? 5. What is the feeding relationship that you have described? 6. What was the ultimate source of energy that started the food chain? 7. In the food chain you just described, which was the producer? 8. Who were the consumers?

Lecture 1.1 Trophic Level in the Ecosystem : 

Lecture 1.1 Trophic Level in the Ecosystem Trophic level – refers to an organism’s position in a food chain. Producers – are photosynthetic; usually green plants and algae; -are called autotrophs because they manufacture their own food; - are producers because they produced food for the consumers.

Trophic Levels in the Ecosystem : 

Trophic Levels in the Ecosystem

Trophic Levels in the Ecosystem : 

Trophic Levels in the Ecosystem Consumers – are also called as heterotrophs; - are organisms that feed on other organisms. Types: Primary consumers (herbivores) – feed on plants. Secondary consumers (carnivores) – feed on meat or flesh of herbivores. Tertiary consumers (omnivores) – feed on both plants (producers) and animals (carnivores).

Slide 11: 

* The trophic level designation for carnivores is determined by the trophic level of the animal that they eat. * Except for some, most carnivores don’t limit their diet to organisms of only one trophic level.

Trophic Levels in the Ecosystem : 

Trophic Levels in the Ecosystem Decomposers / detritivores (detritus feeders) *Detritus – are dead plant materials from leaves fall, fecal wastes of animals, and dead animals. * Bacteria and fungi – are primary detritus feeders; they have unique behavior- they secrete digestive enzymes that breakdown organic matter (e.g. wood) into sugar that they will absorb.

Slide 13: 

Secondary detritus feeders – feed on primary detritus feeders ( protozoans, termites, earthworms)

Activity 1.1 “Where Do I Belong?” : 

Activity 1.1 “Where Do I Belong?” Objective: To identify what trophic level are the given organisms belong. Group Activity

Activity 1.1 : Procedure : 

Activity 1.1 : Procedure Divide the class into groups with 4 or 5 members each. Different pictures of animals and plants will be given to each group. In a manila paper make a table with columns of producers, consumers, and decomposers. Place the picture of organisms in their respective column.

Procedure: : 

Procedure: An envelop containing questions will also be provided to each group. They will write their answers below the table. After 15 minutes, each group will post their work on the board for evaluation.

Questions: : 

Questions: What are producers? Why are they called producers? 2. What are the differences among primary, secondary, and tertiary consumers? 3. What are decomposers? What are their distinctive characteristics being decomposers?

Lecture 1.2 Feeding Relationships: Food Chain and Food Web : 

Lecture 1.2 Feeding Relationships: Food Chain and Food Web Food chain – transfers of matter and energy from one organism to another, as one individual eats another or dies and decomposes. Food web – is a complex pattern of interconnected food chains .

Types of Food Web : 

Types of Food Web Grazing food web – herbivores consume living plant tissues and in turn are consumed by a variety of carnivores. Detrital food web – decomposers / detritivores use organic waste products and the remains of producers and consumers.

Grazing and Detrital Food Webs : 

Grazing and Detrital Food Webs

Activity 1.1 How is a Food Chain Organized? : 

Activity 1.1 How is a Food Chain Organized? Objectives: To observe the interaction between the seedlings, the aphids, and the beetles inside the jar; To explain the difference among these three organisms; To identify the trophic level of the three organisms inside the jar.

Materials : 

Materials 2-wide mouth jars, 2 pieces of flexible screening, 2 rubberbands, bean seedlings in small pots or paper cups, pea aphids, ladybird beetles Procedure: Place a potted bean seedling in each of the two jars. Add aphids to the one jar and cover the jar with screening to prevent the aphids from escaping. Use a rubber band to attach the screening to the jar.

Procedure: : 

Procedure: 3. Add aphids and ladybird beetles to the second jar. Cover the second jar as you did in the first one. 4. Observe and record the difference between the two jars. Record also your prediction of what will happen to the organisms in each jar during the next week. 5.Place both jars in a sunny location. Observe tha jars each day for one week and record your observations each day. Water the seedlings as needed.

Questions: : 

Questions: What happened to the aphids and the seedling in the jar without the beetles? In the jar with beetles? How can you explain this difference? Identify the organisms inside the jar based on their trophic level and sketch the food chain formed among these organisms.

Activity 1.2 Food Web Matching Game : 

Activity 1.2 Food Web Matching Game Objective To distinguish the role of the organisms in the food web. Materials: (per group) gameboard, clue cards, trophic table

Procedure: : 

Procedure: Match the organisms to their position on the food web. The trophic table provides the group with the information that they need to accomplish the task. When your group have decided on the placement of an organisms, you can now look at the clue that corresponds to their placement. Once your group is confident in the placement of all the organisms on the web, tape the organism (strip of paper) in place and present the result.

Questions: : 

Questions: What were the problems that your group encountered? What have you learned in this activity? How is a food chain differ from a food web? What are the two types of a food web? What does an arrow in the food web means?

Lecture 1.3 Ecological Pyramids : 

Lecture 1.3 Ecological Pyramids Kinds: Pyramid of energy – shows that small amount of energy in an ecosystem is transferred at each trophic level. - each time an organism eats another organism, not all energy is transferred to the consumer that eats it. - supported by the Laws of Thermodynamics

Kinds of Pyramid : 

Kinds of Pyramid 2. Pyramid of Numbers – illustrates the total number of organisms at each trophic level in a particular time.

Pyramid of Biomass : 

Pyramid of Biomass Illustrates the total mass of living tissue at each trophic level at anyone time. The biomass largely decreases at each trophic level because much of the consumed energy is not converted to the body of the consumer but is brokendown, so that its stored energy can be released and used by the consumer.

Slide 31: 

As breakdown occurs, chemical elements are released back into the environment in organic state, thus, there is continuous cycle of nutrients from the environment through the organisms and back again to the environment.

Activity 1.3 The Pyramids : 

Activity 1.3 The Pyramids Objective: To be able to identify and quantify the life exist and makes energy flow possible in a selected area. Materials: bond paper, pencil, marking pen, coloring materials

Procedure : 

Procedure Construct an energy pyramid on a bond paper using the data: hectare of grasslands, which produces 1,500 kilocalories in a year supports kid goats which produce 380 kilocalories of meat in a one-year period, which in turn produce a gain of six kilocalories of tissue in a man. Students in pair are given 15 minutes to construct the energy pyramid Presentation of outputs. (Other group can critic on their classmate’s output). Apply this principle to pyramid of Numbers and Pyramid of Biomass.

Expected output: : 

Expected output: Principle’s Applied: The base of energy pyramid is occupied by the producers. The amount of energy flow through a food chain decreases from one organism to the next. Energy decreases as it passed on from one consumer to the other in the food chain. The last organism receives the least amount of energy . 6kcal Human tissue gained 380kcal Goat’s meat produced 1500kcal grass

Evaluation : 

Evaluation Test I. Multiple Choice Test II. Modified True or False Test III. Word Relationships Direction: In the following sets of terms, three are related and one does not. Determine the common characteristics or description among the three terms and identify the term that does not belong. 1. protozoans, bacteria, fungi, butterfly 2.algae, mice, rice grass

Technology Report: : 

Technology Report: Direction: The class will be divided into group of four. Each member of the group is going to read the article and discuss the advantages and disadvantages that they got from the article as well as their reactions. After 15 minutes, each group will report their output to the class.

Application of Technology : 

Application of Technology Biotechnology and Genomics Biotechnology also includes genomics science, the analysis of gene structure and function of an organism. Scientists at DFO carry out aquatic biotechnology and genomics research, in secure land-based facilities, to develop tools to help in the conservation and sustainable use of wild fish stocks, the marine environment, and the development of Canada’s aquaculture industry.

Application of Technology : 

Application of Technology Biotechnology and genomic innovations contribute to the aquaculture industry’s growth and success through the diagnosis and management of disease; and through the assessment of any potential impacts that escaped genetically modified fish might have on wild populations

Application of Technology : 

Application of Technology The application of biotechnology and genomics research to support aquaculture is helping to: improve broodstock selection techniques to generate commercially desirable traits in fish and shellfish (efficient growth, stress tolerance, disease resistance, low maturation rates);

Application of Technology : 

Application of Technology improve understanding of disease-causing agents and disease diagnostic techniques; detect and treat aquatic animal disease; preserve genetic diversity; improve aquaculture practices; monitor and enhance aquatic environmental health; and, protect vulnerable populations and species.

Values Integration : 

Values Integration Recognize interdependence and unity among organisms and their environment. Appreciate the give and take attitude among members of the ecosystem or community. Accept the morality of life. Acquire initiative and self reliance.