GOAL:

To develop an understanding of the interdependence of all organisms and the need for conserving natural resources

Populations interact to form a dynamic community of living organisms within the ecosystem.

Ecology Fl.00 To understand ecological relationships among different populations within an ecosystem

1.01 identify predators and prey.

1.02 compare saprophytes and scavengers and give several examples.

1.03 discuss special symbiotic relationships including: mutualism, commensalism, and parasitism.

1.04 explain the terms "harmful" and "beneficial" with respect to evaluation of ecological relationships.

1.05 explain ways the living community and the physical environment in an ecosystem influence each other.

1.06 relate man's economy and quality of life to these ecological relationships and the balance of nature.

1.07 identify the above ecological relationships among organisms personally observed in nature and seen in nature programs on public television.

I. Roles of predators and prey
A. Predators
B. Prey
II. Roles of saprophytes and scavengers
A. Saprophytes
1. Bacteria and fungi
2. Recycling minerals
B. Scavengers
1. Examples of scavengers
2. Part-time scavengers
III. Symbiosis
A. Mutualism
B. Commensalism
C. Parasitism
IV. "Harmful" and "beneficial" ecological relationships
A. Individual and populations
B. Short term and long term situations
V. Interactions with the physical environment
A. Items necessary for survival
B. Changes in the physical environment
VI. Problems in ecosystems
A. Losses in the physical environment
B. Losses in the living community

COMPONENT OF SCIENCE: Unifying Concepts of Science

GOAL:

To enable students to acquire scientific knowledge by applying concepts, theories, principles and laws from life/environmental, physical and earth/space sciences.

2.5 CHANGE - Interactions within and among systems may result in changes in the properties, position, movement, form, or function of systems.

2.5a Everything is constantly changing; rates of change vary over a wide scale with a great variety in patterns of change.

BENCHMARK: Human interaction accelerates rates of change in the biosphere.

2.5b Cycles of change can be extended in scales of time, space and material.

BENCHMARK: Interdependence conveys a need for all organisms within the environment to develop a natural, uninhibited, rate of change.

BENCHMARK: Predictions can be made regarding the extent of change resulting from human interaction with the biosphere.

TIME REQUIRED:

Instructional Objectives 1.01, 1.02, 1.03, and 1.07 - two class periods plus additional time for activities and enrichment, Instructional Objective 1.04 - two class periods plus additional time for enrichment activities and research, Instructional Objectives 1.05, and 1.06 - two class periods plus additional time for activities and film

Note cards, markers, nature magazines, encyclopedias, wildlife resource books, video-tapes of nature programs

Carrion, commensalism, ecosystems, living community, mutualism, parasitism, physical environment, predators, prey, saprophytes, scavengers, symbiosis

This classroom connector addresses Instructional Objective 1.01, 1.02, 1.03 and 1.07.

(Have students write the names of any three predators which live in different habitats. Then have students write the names of each of their predator's prey.) In this lesson we will study predation and a variety of complex interrelationships which living things share.

Predators are consumers that catch and eat other consumers for their food. Prey are the consumers which are killed and eaten by the predators. Predators and prey are both necessary parts of ecosystems.

There must be more prey than predators as each predator eats a great deal of prey during a lifetime. Predators have characteristics to help capture their prey; prey have characteristics to help them avoid capture.

Predation is important in controlling overpopulation of the prey species. It also helps select for a healthy breeding population of the prey species by eliminating the weak individuals and those susceptible to disease.

(Have students write the names of predators in various animal groups such as (Mammals, birds, reptiles, amphibians, fish, insects, other arthropods, and other animals) and name their possible prey. Have the students discuss possible consequences of loss of certain predators in an ecosystem.)

(This is adapted from "Interview a Spider" on page 13 of the Project Wild elementary activity guide and from the 1989 National Wildlife Week materials. Have each student pick a predator. Possible predators include:

African lion American toad black bear black widow spider black-footed ferret bottle-nosed dolphin coyote electric eel gavial

Gila monster golden eagle great barracuda great white shark leopard seal osprey peregrine falcon piranha

Portuguese man-of-war preying mantis raccoon red fox sea otter snow leopard timber rattlesnake vampire bat many others

Have students research their chosen predator. Students should take turns interviewing and being interviewed themselves. They should ask and answer questions about particular predators' habits, adaptations, habitats, life style, plus other interesting information. The interviewer should take good notes and then write and illustrate a magazine article about the predator they interviewed.)

Saprophytes are organisms that feed on dead organisms or on nutrients in the soil that were once parts of organisms. Many bacteria and fungi are saprophytes. These saprophytes are helpful in getting rid of the dead and in recycling nutrients in the dead into simpler materials which may be used by other producers.

Scavengers are organisms that feed on refuse or dead organisms called carrion. Many predators are part-time scavengers. The lion, coyote, and crow are part-time scavengers. The vulture, dermestid beetle, and blow fly are full time scavengers. Scavenger in removing dead organisms from an ecosystem.

(Lead the students on a field trip into a wooded area to examine bracket fungi, mold, and other fungi on dead trees, leaf litter, and on fallen logs. You may place a fresh road-killed rabbit or opossum in the wooded area and examine it later for evidence of scavengers or decomposers.)

(Have students write answers to the following: Name the organisms which kill and eat other organisms. (Predators) Name the organisms which are eaten by the predators. (Prey) Give ways predation is necessary. (Feed the predator, balance of nature, control prey populations) Name organisms which feed on refuse and carrion. (Scavengers) Name organisms which decay dead organisms. (Saprophytes) How are saprophytes and scavengers necessary? (Removing the dead from the ecosystem and recycling their nutrients))

"Muskox Maneuvers," Project Wild --(Secondary)

"Spider Web Geometry," Project Wild--(Secondary)

"Birds of Prey," Project Wild--(Secondary)

"Owl Pellets," Project Wild--(Secondary)

Turtle Hurdles," Project Wild--(Aquatic)

"Hook and Ladder," Project Wild--(Aquatic)

"Predator Prey," Project Learning Tree.

Watch any nature programs on public television and identify predators, prey, saprophytes, and scavengers.

Identify predators, prey, saprophytes, and scavengers in nature magazines such as:

Ranger Rick
National Wildlife
Tennessee Conservationist

This classroom connector addresses Instructional Objective 1.04.

(Have all students write the answers Helpful, Harmful, or Neither to the following questions.)

A tick may live in a dog's ear. Is this harmful, helpful, or neither to the dog? (Harmful) to the tick? (Helpful)
A cattle egret may eat insects disturbed by walking cattle. Is this harmful, helpful, or neither to the egret? (Helpful) to the cattle? (Neither)
In this lesson we will study three different types of relationships in which two organisms of unlike species live together in close association. We will learn many examples of each type.

Symbiosis is the living together in close association of organisms of two different species.

Mutualism is a close relationship between two organisms which is helpful to both organisms. Examples of mutualism include: oxpecker-rhinoceros; algae-fungi in lichens; and protist-termite.

Parasitism is a symbiotic relationship in which one organism, the parasite, spends much or all of its life in or on another organism, the host. The parasite is dependent upon the host for food. The parasite benefits from the relationship, and the host is always harmed. Examples of parasitism include: tick-dog; tapeworm-human; eel-lake trout.

Commensalism is a symbiotic relationship in which one organism is helped and the other is neither helped nor harmed. Examples of commensalism include: remora fish-shark; and prairie dog-burrowing owl.

("Good Buddies" from page 89, Project Wild (Secondary)

Students research pairs of animals, play a card game, and classify the pairs of animals according to three major forms of symbiotic relationships. The major purpose of this activity is for students to become familiar with the concept of symbiosis as one example of interdependence in ecological systems.

Procedure:

1. Make up several decks of cards--one deck for every five or six students. Each deck should contain 16 pairs of symbiotic relationships and one "no buddy" card. Examples of pairs:

barnacle/whale cowbird/buffalo bee/marabou stork hermit crab/snail shell aphid/ant pilot fish/shark oxpecker/Rhinoceros damselfish/sea anemone

gull/brown bear ostrich/warthog yucca moth/yucca tick/dog cattle egret/cow ostrich/gazelle moth/sloth honey guide bird/badger

protist/termite vitamin K bacteria/human dodder/marigold orchid/tree mosquito/human clown fish/sea anemone tetanus bacteria/human algae/fungi in lichen

There are other pairs which may be used. You will not use all of these.

2. Assign students (or let students draw) the names of organisms on the cards to research each member of the pairs. Some students may research more than one organism.

3. questions should be answered. Why do the pairs live together? What advantages and disadvantages do they provide each other? What would happen if one of them wasn't there.

4. Students can report their research to the class.

5. To play the card game, the class should be divided into groups of five or six students.

6. Shuffle and deal out all cards. Play starts to the left of the dealer and rotates in a clockwise manner. Each player draws one card from the player to his or her left. After the player has drawn a card, that player may lay down all cards in his or her hand which form symbiotic pairs. When a player does not have any cards left in his or her hand the game is over. The player with the largest number of pairs at the end of the game is the winner. One player is left holding the "no buddy" card at the end of the game.)

(Have the students name their pairs and explain why each pair is mutualism, parasitism, or commensalism.)

(Have the students write the answers to the following:)

1. Two unlike organisms living together. (Symbiosis)

2. Symbiosis that helps both. (Mutualism)

3. Symbiosis that helps one and hurts one. (Parasitism)

4. Symbiosis that helps one and is neither harmful or helpful to the other. (commensalism)

(Have students identify symbiotic relationships observed in nature programs on public television.

Have students identify symbiotic relationships identified in nature magazines.)

This classroom connector addresses Instructional Objective1.05, and 1.06.

(Have all students list on paper several things human beings have done which have had adverse effects on both the living and non-living environment. Give students time to write several answers).

An ecosystem includes all the living populations in an area interacting with each other and with the physical (non-living) environment. Organisms must have food, water, shelter, opportunities for reproduction, living space, and other things from the environment in order to survive.

As populations change, they may alter the physical environment. As the physical environment is changed the living community is altered.

(Have all students write on paper one way living things can change the environment. Give students time to write several answers. There are limitless answers such as beaver, kudzu, Dutch elm fungus, over-populated species, exotic species, ornamental plantings, and many others. Do not include human beings in this part of the lesson. Have the students name their organism and explain how they have changed the environment.

Have all students write on paper one way a change in the physical environment has influenced a living thing. Give students time to write several answers. Environmental changes might include water pollution, air pollution, pesticide use, soil erosion, channelization, radiation, construction, and many others. Have students share their change in the physical environment with the class and tell how it has influenced a living thing.)

The terms "harmful" and "beneficial" have different meanings for ecological populations and individuals. Situations which are harmful or beneficial to an individual may be the opposite to an entire population or to other populations in an ecosystem or to the physical environment. Situations which may seem beneficial to some humans in the short term may be harmful to an ecosystem or the biosphere in the long term.

As humans have pursued a higher standard of living and a better quality of life, both the physicals environment and ecological populations have suffered. Air, water, soil, mineral resources, and other parts of the physical environment may be damaged by human activities. Many species of living things have become threatened, endangered, or extinct due to human activities in the environment.

(Have all students write on paper one way human activities have severely altered some part of the physical environment. There are very many possible answers.

Have all students write the name of one organism which has suffered because of human activities and explain the situation. There are very many possible answers.)

(Show the class the 16 mm film, The Lorax, from the Tennessee Wildlife Resource Agency. This is from the Dr. Seuss book, The Lorax. It is about the destruction of the environment due to the incessant demands of consumers.)

Equate the ideas in the story with real life situations in present-day society. Describe values which appear to be important in the story, and identify any present-day counterparts to these values.

("Enviro-Ethics," Project Wild, (Secondary) Students will be able to: 1) distinguish between actions that are harmful and beneficial to the environment; and 2) evaluate the appropriateness and feasibility of making changes in their own behaviors related to the environment.

1. Involve the students in discussions about the impact each of us has each day on aspects of the environment--from using electricity to making breakfast to putting on clothes that were derived from some natural resources and transported to us by some means, to use of varied products we choose and employ each day, to our choices of recreation and entertainment.) We are consumers, and our impact is formidable.

2. Ask each student to work alone to devise a "Personal Code of Environmental Ethics". Emphasize the importance of the code being real for each individual student. The code should take into consideration daily actions that are harmful to the environment, and those which are beneficial. The students should consciously create their code based on actions they believe are beneficial, or at least not harmful, to elements of the environment. We will always have some impact; we make choices about the kinds of impacts we make, their extensiveness, etc.

3. Ask students to share their ideas and commitments. The purpose is for each student to evaluate his or her own priorities, in a responsible consideration of day-to-day actions that affect the environment, but not to be actively critical of another student's approach to the same problem. Each student is simply encouraged to take responsibility for his or her own actions.

4. Encourage the students to try using their codes, keeping track of how easy or difficult it is for them to live by them.)

(Have students write answers to the following:
1. Name several things organisms must get from the environment in order to survive. (Air, water, food, space, shelter, others.)

2. Name ways human beings have destroyed these necessary factors in the environment. (Many answers)

3. Name organisms which have suffered due to our actions. (Many answers)

Close your eyes and follow yourself through a typical day. What natural resources do you use? What choices do you make that have an impact on the environment. What choices do you make that have an impact on wildlife and its habitat? What choices do you make that have an impact on people, here and elsewhere? If you could, what things, if any, would you change about your daily life in order to have a more beneficial, or less harmful, impact on the environment? (This is still from "Enviro-Ethics," Project Way.)

(Other activities which might be employed are:

"Habitat Lap Sitn," Project Wild, (Secondary)

"Ants on a Twig," Project Wild, (Secondary)

"Oh Deer," Project Wild, (Secondary)

This is the time this file has been accessed since 11/16/96.

The University of Tennessee at Martin is not responsible for the information or views expressed here.

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