FINDING THE STATED MAIN IDEA
"What's the point?" Good readers ask themselves this question as they read to help them get to the heart of the matter. When you try to find out the most important point a writer is making, you are looking for the main idea. A main idea is the key point that a speaker or writer is making. The main idea tells what the whole passage is about.
In most cases, the main idea will be directly stated in a passage. Other times, you will have to infer the main idea from clues in the text.
WHAT TO LOOK FOR
- Read the Title
Every unit, chapter, and section in Biology: The Web of Life has a title. You can find the title in large type at the beginning of each part of the textbook. Titles are very helpful in finding the main idea of a passage because they often give hints about its content. Think carefully about what the title means and ask yourself, "Based on this title, what can I expect the unit, chapter, or section to discuss?"
- Read The Big Idea!
Most sections in Biology: The Web of Life start off with The Big Idea! This feature directly states the main idea of one or more of the sections that follow.
- Read What You'll Learn
To the left of main text, you'll find a thin column. It contains a section called What You'll Learn. This feature contains two sections: Ideas and Words. The Ideas section list several key points in the chapter.
- Read the Section Opener
Under the title, each section has a brief paragraph accompanied by a photograph or illustration. This paragraph introduces the main idea through a specific example. This type of feature is often called a "teaser" because it also gets your attention and makes you want to read on. For example, on page 130, the section opener for Section 6.1 asks, "Can a wallflower grow?" Read the answer and notice how it fits with the title, The Big Idea!, and What You'll Learn.
- Find the Topic
The topic of a passage is what it is about. You can find the topic by skimming the passage and seeing what it describes. Look at the head for each part of the section. As you skim the passage, ask yourself, "What subject is the passage describing?"
For example, on page 147 the first part of Section 6.5 is called Intermediate Inheritance. Skimming gives you the topic, but it doesn't give you any details. This part of the section reveals the description of genes that show a form of intermediate inheritance rather than having purely dominant and recessive alleles. The topic of this section, then, will be forms of intermediate inheritance. The main idea will be a statement about this topic.
- Look for the Main Idea in the Topic
Sentence
After you find the topic, look for the sentence that gives the most general information about the topic. This will be the main idea. You will know that you have chosen the correct sentence if it gives an overview or introduction to the topic by explaining what the entire passage will discuss. The last two sentences of the first paragraph on page 147 state the main idea: Instead of having purely dominant and recessive alleles, many genes show an intermediate form of inheritance.
Textbooks such as Biology: The Web of Life are written to convey information clearly and concisely. As a result, they will almost always directly state the main idea in a topic sentence. It will be the broadest statement in the passage. Every detail, or small piece of information in the passage, gives information to support or explain the main idea. The following example is from the second paragraph on page 130.
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Main Idea: The Topic
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detail |
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Today's domestic dogs are descended from a wild, wolfish ancestor. |
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Here are sample sentences that directly state the main idea of THE HISTORY OF GENETICS on pages 130131. Each sentence tells what the paragraph is about:
1. Genetics is the scientific study of heredity.
2. A trait is a characteristic that can be passed from parent to offspring.
3. It was not until scientists discovered the cellular basis of life that the inheritance of traits was better understood.
4. But the relationship between chromosomes and traits was not always understood.
5. The first clues to understanding inheritance came from Gregor Mendel, one of the most outstanding scientists in the field of genetics.
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Tips for Finding a Stated Main Idea As you read, ask yourself these three questions: What is the topic?
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TRY IT
1. Read the first paragraph under Mendel's Conclusions on page 133. What is the topic sentence?
2. What is the title of Section 6.3 on page 138? What will this section be about?
Click here to check your answer to TRY IT!
To practice what you've just learned, go to Worksheet 2.1
To learn about another reading strategy, go to Reading Strategy 2.2.
Reading Strategy 2.1
| Worksheet 2.1
Reading Strategy 2.2 | Worksheet
2.2
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