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### Course: 6th grade reading & vocabulary >Unit 3

Lesson 5: Reading for understanding: informational text; Boyan Slat

# How can a text have two or more main ideas? | Reading

Texts can contain more than one main idea: multiple, equally-important arguments can be threaded through a single text. To identify if a passage has two main ideas, ask yourself if both ideas are equally important or if one is just supporting the other.

## Want to join the conversation?

• At David said algae would take over the ocean if sharks were extinct. But wouldn't it be, like the exact opposite, because there would be more fish eating the algae?
(128 votes)
• Your logic's correct, but the story David reads out is missing a step. Sharks eat smaller fish, but those small fish eat even smaller organisms that eat algae, like shrimps and clams and things. When the sharks disappear, the predatory fish populations will grow, and the smaller organisms' populations will decrease as a result. They are the predator of algae, which means algae will grow unchecked.
(171 votes)
• Man I can’t tell if some of these people are teachers or just smart students
(111 votes)
• Everyone can be a teacher, even you. There are things you know that others do not, and you can choose to help learn. For example, one of my daughters is only four years old, but she teaches my one year old daughter how to walk, jump, play, and even sings her songs and is helping show her colors.
(81 votes)
• At David sing's a song
(85 votes)
• How can you be in two places at once when you're not anywhere at alllll!
(51 votes)
• Is David the best teacher?
(58 votes)
• Yes definitely!
(44 votes)
• If we do the splits, arent we going in 2 directions at once?
(59 votes)
• Interesting point. I suppose you could think of it as going in three directions even - left and right for each leg, and your torso going down.
(43 votes)
• did anyone listen to David singing at the end?? Or was it just me? David is one of the funniest in khan academy.
(71 votes)
• Yea bro he's the best
(11 votes)
• "hE's So sCaRy" got me cracking up.
(44 votes)
• that shark is the scariest thing i have ever seen in my life 🦈
(37 votes)
• these are all opinions about the shark because that is what you think.
(18 votes)
• Technically your body can be split in half right? So then it can travel to 2 places at the same time.

#Im-joking-and-im-not-a-murderer
(32 votes)
• Very smart indeed
(18 votes)
• give this man a raise
(13 votes)

## Video transcript

- [David] Hello, readers. Today I wanna begin with a brief aside about physics. Unless you're like a quantum particle or something, it's not possible to be in two places at once, nor is it possible to travel in two directions at once. Right, if I'm on a train from Chicago to Pittsburgh, I can't simultaneously be on a train from Chicago to Omaha. So my body can't travel in two directions at once, but my mind can. What, what? I know, it is possible to think two ideas at the same time, ideas that are equally important but may not necessarily support one another. I can be thinking, it's hot outside and I'm late for my train, and those two ideas can have equal weight in my mind. The same thing can happen in texts. An essay, or an argument, or a book can have two or more main ideas. It's a train that can go east to Pittsburgh and west to Omaha at the same time. This is a confusing idea. When you look at an essay, you think, what's the main idea in this text? What is the author trying to tell me, or what position are they trying to convince me of? So how can there be room for more than one idea? How can we tell that a piece has two main ideas and not just one idea with supporting evidence? All right, here's an example of two main ideas. Sharks are deadly predators and fierce hunters. They hunt with sharp teeth, incredibly sensitive noses, and the ability to sense the electrical current of a living body. Many people are afraid of sharks, because encounters with them can be fatal. That's paragraph one. However, sharks need to be protected, because they are important to ocean ecosystems. Their roles as high-level predators ensures that they maintain population levels of smaller fish, which in turn maintains the balance of ocean plant life. If there were no sharks, algae could take over the ocean. Now, both of these paragraphs are about sharks. So in once sense, it's true that the passage as a whole is about sharks. Gonna just draw a little shark. He's so scary. Look at those very sharp teeth. (laughs) Anyway, the topic is sharks, but what's the idea here in each paragraph? Paragraph one says, "Sharks are deadly, and here is why." And paragraph two says, "It's because of their deadliness "that they need to be protected, "because big predator species balance ecosystems." These are two ideas that are separate but interrelated. Sharks are deadly. Sharks need protecting. On its face, those two ideas almost seem like they contradict each other or cancel each other out, but they are two separate threads that each support the overall topic of sharks. They are two distinct ideas here with equal importance. This passage teaches us that A, sharks are deadly, so they are scary, and B, deadly animals must be protected, because they are important. Neither of these ideas are more or less important than one another. They are both main ideas. When you're considering whether or not there are two or more main ideas, ask yourself, are both x and y equally important understandings from this passage, or is it just one idea supporting another? So with this in mind, you too can learn to travel in two directions at once with the power of your mind and the power of reading. You can learn anything, David out. ♪ How can you be in two places at once ♪ ♪ When you're not anywhere at all ♪