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Week 3 - Producers, Consumers, Decomposers, Food Chains and Webs, and The Water Cycle

Week 3 - Producers, Consumers, Decomposers, Food Chains and Webs, and The Water Cycle

Site: AB Course Sharing Hub
Course: Science 7 LearnNet
Book: Week 3 - Producers, Consumers, Decomposers, Food Chains and Webs, and The Water Cycle
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Date: Thursday, 18 July 2019, 9:36 PM

 

Lesson 1


Activity 04 - LESSON 1: Ecosystems have Interactions among Producers, Consumers, and Decomposers
ACTIVITY A: Producers, Consumers, and Decomposers

Textbook Readings

Science in Action 7
page 26 to 33
or

Science Focus 7
pages 40 to 41
and
44 to 45



All living organisms must interact for two reasons (biologically speaking). First, substances must be re-cycled and second energy must be transferred from one organism to another. These interactions can be quite complicated. To study organisms we must first group them. You already studied some groups of organisms but when talking about the transfer of energy from one organism to another scientists group animals according to what they eat.

Plants are called producers because they use the energy from the sun to create (or produce) food. They transfer energy from the sun into food. They recycle nutrients from the ground back into food. They recycle water from the ground and release it into the atmosphere. They also recycle gasses.
Some organisms eat only plants. They are called either herbivores or primary consumers. They transfer energy and nutrients from plants into meat in their bodies. They recycle some nutrients back into the ground when they release waste. They recycle water and gasses when they breathe.
Some organisms eat only other animals. They are called carnivores or secondary consumers. They transfer energy from the meat of the primary consumers into the meat their own bodies. They recycle some nutrients when they release waste. They recycle water and gases when they breathe.
Some organisms eat only dead plants and animals. They are called decomposers. They release energy trapped in dead plants and animals back into the atmosphere. They also recycle many the nutrients trapped in dead plants and animals back into the soil so that the plants can use them to produce food. They also recycle gasses when they breathe. In terms of plants remember: If it is green it is a producer (grass, moss). If it is not green it is usually a decomposer (mushrooms, fungus)
Exercise 2.1: Producers, Consumers, and Decomposers

 


Copyright © 2001, the Crown in Right of Alberta, as represented by the Minister of Learning, Alberta Learning, 11160 Jasper Avenue, Edmonton, Alberta T5K 0L2

Picture and Photos:( For specific picture reference view page source.)
Copyright The Essentials Clip Art CD, MaGlas-l.gif, copyright 2001
www.freefoto.com


Lesson 2


Activity 04 - LESSON 2: Food Chains demonstrate the flow of energy in Ecosystems

ACTIVITY : Food Chains
There was an old lady who swallowed a fly, I don't know why she swallowed the fly..."

When we are young, we learn songs that appear to be nothing more than nonsense. However, if we look closely at this song we see how energy is transferred through the food chain. The old women swallowed a spider to catch the fly, she swallowed a bird to catch the spider, and so on. Now the only reason she would choose to swallow these things would be to get rid of the fly, by sending in its predator."

FOOD CHAINS
Food-why do you eat it? Yes, it tastes good, but can you survive without it? All living things require energy to survive. Plants are able to make their own food, but animals need to get their food from another source, so eating is important. The ultimate source of food and energy for living things is the Sun. All food chains can be traced back to the Sun as the source of energy.

In a food chain, energy and nutrients are passed from one organism to another. By studying feeding habits, ecologists can trace the flow of energy through an ecosystem. In a temperate forest, a fox may prey on a bluebird, which consumed a spider, which ate an aphid, which was munching on a blade of grass. The grass was busy creating its own energy from the Sun. A food chain always begins with a plant-a primary producer.


But the fox does not always eat a diet of bluebirds, so the fox could also be a member of a different food chain:


Required Readings

Science in Action 7
pages 35-38
or

Science Focus 7
pages 42

A food chain is made up of producers and consumers. Producers are considered autotrophs, which means they can make their own food. Consumers take in food. They are considered heterotrophs, or living things that can not make their own food. A food chain will contain several kinds of consumers. A primary consumer eats the producer, a secondary consumer eats the primary consumers, the tertiary consumers eat the secondary, and so on

The position of a species in the food chain is called its trophic level. If a hawk eats a mouse, then you would say the hawk has a higher trophic level in the food chain. The number of trophic levels in a food chain is the same as the number of species in the chain. There are rarely more than six trophic levels in one food chain because the amount of energy passed along at each level goes down at each stage. The same species may participate in many different food chains at different trophic levels. So in the example above, the spider would be the secondary consumer as well as the holder of the third trophic level.

Click here for Rainforest food chain/webs.

Copyright © 2001, the Crown in Right of Alberta, as represented by the Minister of Learning, Alberta Learning, 11160 Jasper Avenue, Edmonton, Alberta T5K 0L2 Picture and Photos:( For specific picture reference view page source.)
Copyright The Essentials Clip Art CD, MaGlas-l.gif, copyright 2001
www.freefoto.com

Lesson 3


Activity 04 - LESSON 3: Food Webs



Textbook Readings

Science in Action 7
pages 39 to 42
or

Science Focus 7
page 43

ACTIVITY : Food Webs

A community of organisms may contain hundreds of different species. Each species can be involved in numerous food chains. Therefore each food chain can be interconnected with other food chains to produce a larger network, called a food web. Food webs can grow to be extremely complicated. Going back to the temperate forest, if you were to combine all the food chains in that ecosystem you would produce a food web.



What would happen if an organism is removed from the food web?

Creating a Food Web

Materials:

String, or thread.
Thumb tacks
Labels or masking tape.
A large piece of card board.

List of organisms:



A large tree
a bush with berries
log
mushrooms
berries
fern
wild grass
slaamander
slug
lichens
seeds
elk
squirrel
earthworms
bacteria
crows
hawk
wolves and fox
You are welcome to add other organisms to the list if you wish.
1. On the labels or masking tape, write the name of each of the organisms from the list above. Stick these to the head of the tacks.

Planning. Think how you will place the tacks on the board to create a food web. Place the producers near the middle of the board. You may wish to use a pen and paper to make a quick food web.


2. Place the tacks on the cardboard, starting with the producers, then place the first order consumers and the decomposers on next and finally the secondary and tertiary consumers.
3. Now attach a string or thread to create a food chain. Make sure that you wrap the string around the tack several times with each connections.
4. Once you have your picture done, make a sketch of how it looks and put it in the student Response area.
5. Now imagine that a farmer near by sprays his field to get rid of the wild grass. It is a windy day and the herbicide blows into your ecosystem. All the wild grass dies.
6. Using a pair of scissors, cut all the connections to the wild grass. Make the cut as close to the grass as possible. Remove the wild grass tack. Now try to find a replacement for your organism by tying the string to another producer that the organism may eat. If the string is too short to reach another producer then leave the string limp on the board.
7. Now check each first order consumer (or herbivore) and make sure that there is a producer attached to them at some point in the web. If not then you must cut the connections to that first order consumer. Now try to find new connections for any string that you have cut. Remove the tacks of any first order consumers that do not have another source of food.
8. Continue to check the second order consumers and tertiary consumers. Then check the decomposers.

Exercise 2.3: Food Webs

Copyright © 2001, the Crown in Right of Alberta, as represented by the Minister of Learning, Alberta Learning, 11160 Jasper Avenue, Edmonton, Alberta T5K 0L2

Picture and Photos:( For specific picture reference view page source.)
Copyright The Essentials Clip Art CD, MaGlas-l.gif, Copyright Dave Taylor's Wildlife Reference Library

Lesson 4


Activity 04 - LESSON 4: Matter Cycles in Ecosystems

INTRODUCTION

All ecosystems and biomes in the biosphere past, present and future are interconnected through cycles. There is no way for water, gasses, and nutrients to enter and leave the earth, therefore, they must be recycled and reused over and over again.


Required Readings

Science in Action 7
pages 44 to 46
or

Science Focus 7
page 51

LESSON A: The Water Cycle
The water that we drink has been recycled over and over again since the beginning of time. This means that the same water that existed on Earth millions of years ago is still here. The water that you drink may have been in a dinosaur or maybe in the king of England. Water is recycled very rapidly around the world so the water that falls on you may it has been in a lion or in a tree in the rain forest. The water that you breath out may save the life of a future creature that you will never see. All people animals, plants that have ever existed, and that ever will exist are connected by the water cycle.

Exercise 2.4: The Water Cycle



OPTIONAL ACTIVITY - Observing the Water Cycle

QUESTION

Is it possible to see the water that plants release during transpiration?

MATERIALS REQUIRED

2 clear plastic bags
2 elastics or a twist ties
a green plant with leaves
a branch with no leaves

PROCEDURE


1. Carefully wrap a plastic bag around the leaves of a tree, plant or the needles of an evergreen tree. Use the elastic or twist tie to attach the bag to the branch.

2. Do the same thing to a plant branch with no leaves or needles.
3. Leave the plant for 24 hours and then come back and observe.
4. Record your observations.

ACTIVITY 2.4C: Oxygen and Carbon Dioxide Cycle ~ The Cycle of Life
Required Readings

Science in Action 7
pages 46
or

Science Focus 7
page 49

The Carbon Dioxide/ Oxygen Cycle is a careful balance between plants and animals. Mankind is beginning to change that balance.

Watch the following Flash animation and then answer the questions that follow. You must be connected to the Internet to view.

You must be connected to the internet to view this animation
Click here
ACTIVITY D: Matter and Nutrient Cycles
Life is created from death. Without death, life could not continue because death and then decomposition release nutrients to be used again and again. In some ecosystems the nutrients are recycled rapidly and in other ecosystems the nutrients are released very slowly. The speed at which dead plants and animals decompose and are re-used determines the quality of the soil.

Which do you think will have soil rich in nutrients and humus? A rain forest or a forest found in Alberta? Check out this Rainforest Biome web site (double click on the blue type once you are connected to the Internet) and read the sections titled "soil" and "nutrient recycling." You find this page by going to "Exploring the Rainforest." Scroll through this page and you will find it. Then answer the questions that follow.

Copyright © 2001, the Crown in Right of Alberta, as represented by the Minister of Learning, Alberta Learning, 11160 Jasper Avenue, Edmonton, Alberta T5K 0L2

Picture and Photos:( For specific picture reference view page source.)
Copyright © 2000-2001 www.arttoday.com, Copyright © 2001 Jeannie Charrois, Copyright © The Essentials Clip Art CD, MaGlas-l.gif, Copyright © 2001, The Object Series 10, Copyright © 2001 Shauna Burke

Section 2 Notes

You will have two opportunities to write this section quiz. This quiz consists of 10 questions. Use the results from your 1st attempt to help you prepare for your second attempt. Your best score will be taken as your assessment mark. You have 10 minutes to complete this multiple choice quiz. Remember to do this quiz under testing conditions without texts, aids, or help.

Click the icon to go to the quiz.