Activity 2.2 - Reading about ecosystems and biomes (individual and pair)
Pre-reading:
Think first about what an ecosystem is. How would you describe your ecosystem? You are going to read a text about ecosystems and then do a closer examination of biomes.
What is a biome?
A biome is a large area with similar flora, fauna, and micro-organisms. Most of us are familiar with the tropical rainforests, tundra in the arctic regions, and the evergreen trees in the coniferous forests. Each of these large communities contains species that are adapted to varying conditions (availability of water, temperature and soil type). For instance, polar bears thrive in the Arctic while cactus plants have a thick skin to help preserve water in the hot desert.
The major biomes: mountains (high elevation); tundra; temperate forest; marine/island; desert; tropical dry forest; cold climate forest; grassland savannah; tropical rainforest
What is an ecosystem?
The words ‘ecosystem’ and ‘biome’ are often confused. There is a slight difference in meaning between the two words. An ecosystem is usually much smaller than a biome. A biome can be thought of as many similar ecosystems throughout the world that are grouped together. An ecosystem can be as large as the Sahara Desert or as small as a puddle.
Ecosystems are dynamic interactions between plants, animals, and micro-organisms and their environment, working together as a functional unit. Ecosystems will fail if they do not remain in balance. No community can carry more organisms than its food, water and shelter can accommodate. Food and territory are often balanced by natural phenomena such as fire, disease, and the number of predators. Each organism has its own role to play.
How humans have affected the ecosystems
We have affected ecosystems in almost every way imaginable! Every time we walk out in the wilderness or bulldoze land for a new parking lot we are drastically altering an ecosystem. We have disrupted the food chain, the carbon cycle, the nitrogen cycle, and the water cycle. Mining minerals also takes its toll on an ecosystem. We need to do our best not to interfere in these ecosystems and let nature run it course.
[Adapted from the Department of Environmental Affairs and Tourism http://soer.deat.gov.za/themes.aspx?m=492&amid=3444]
1. Use your dictionary and thesaurus to find the meaning of the following words:flora; fauna; evergreen; coniferous; thrive; temperate; dynamic; drastically
2. Write out answers to the following questions.
a. Explain the difference between a biome and an ecosystem.
b. What is needed to make up an ecosystem?
c. What are the consequences of human activity, such as property development or building a dam, for an ecosystem?
3. You will be familiar with to some extent with most of the biomes mentioned above. Below is a table with the names of the six major biomes in the first column and a brief description in the second column. Link them up.
| The six major biomes | Description |
| 1. This biome occupies about one fifth of the Earth’s land area. This biome accounts for two thirds of land plants and contains about 70% of carbon present in living things. | |
| 2. This is the coldest of the biomes. This is a treeless plain with frost-moulded landscapes, extremely low temperatures, little rain and poor nutrients. | |
| 3. This biome has a low salt content – usually less than 1%. It includes ponds, lakes, streams, rivers and wetlands. | |
| 4. This biome is dominated by grasses rather than larger shrubs or trees. It includes savannahs and temperate areas. | |
| 5. This biome covers about one fifth of the Earth’s surface and occurs where rainfall is less than 50 cm a year. | |
| 6. This biome covers about three quarters of the Earth’s surface. It includes oceans, coral reefs and estuaries. |
Discussion
Remember the rules for group discussion:
Be polite and encouraging.
Give everyone a turn.
Don’t interrupt.
Use appropriately formal language.
Practise these rules in the activity below.
Activity 2.3 - Planning for and holding a discussion (group)
Organise yourselves into groups of four. You are going to discuss the biome in which you live. As a preliminary activity, discuss which biome your area falls under and how you know.
There are four aspects of your biome that your group will discuss:Its extentIts characteristicsWhat it was like a hundred years agoWhat human activities have occurred in the biome
You will each do research on one of the aspects. Decide who will do which.
Your teacher can do a quick check to see if you all agree on what your biome is.
Use the library or the Internet to do research on the aspect that has been assigned to you. Make notes so that you can return to class and inform your group of what you found. The rest of the activity depends on your doing this.
When you regroup, take turns telling the others about your research. You can make notes as you listen to the others. After each person has spoken, you can ask any questions you need to so as to clarify everything. When you are all satisfied with this part of the activity and all four of you have all the information, you can move on to the next step.
As a group you will now link the different inputs by discussing what the effects of human activities have been on your biome. Make notes when you have finished. As a group you can compare and amend your notes. You will use them in the following activity.
Paragraph writing
You wrote a paragraph in Activity 2.1 without any guidance about how to go about this, except what you have learnt in previous years. What criteria did you use to write and to check your partner’s work? Both these tasks would have been more focused if you had guidelines on paragraph writing, and a checklist or rubric to check your partner’s against. Here is this information to help you improve your paragraph writing.
Information box
A paragraph has a topic sentence that states what the paragraph is about. For example: ‘There are several explanations put forward for why the dinosaurs became extinct.’ This topic sentence informs us that the paragraph will give us explanations about why the dinosaurs became extinct. We expect to hear what the ‘several explanations’ are in the remainder of the paragraph. However, the topic sentence is not always necessarily the first sentence of the paragraph.
The supporting sentences will all be linked to the topic sentence. We do not expect to read about the size of dinosaurs unless this has something to do with why they became extinct. Linking words such as ‘this’, ‘however’, and pronouns such as ‘it’, ‘they’ should be used to relate the sentences to each other. It is a good idea to vary the length of the sentences as well