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Learning how to distinguish among facts, reasoned judgments and speculation will help you evaluate the claim the writer is making. Good scientific writers make claims that are supported with evidence that includes facts and research findings. They explain their claim through their reasoning that clearly shows how the evidence supports the claim. When scientists do not back up their claims with evidence and reasoning, they are speculating. Speculation means that the writer is making a claim but not supporting it with appropriate and/or sufficient evidence and reasoning.
Good scientific writers make claims that are supported with evidence that includes facts and research findings.
It is important for readers to have the skills necessary to evaluate such scientific texts for accuracy by knowing how to look carefully at the evidence provided. Read the following excerpt from the Newsela article "Humans bringing Earth its 6th mass extinction, but can stop it.”opens in new window Next, review the table below to learn how to distinguish between supported claims (reasoned judgments) and unsupported claims (speculation) as you evaluate text from the article.
1 Cataclysmic events drove the first five mass extinctions in Earth’s history. An asteroid ended the age of the dinosaurs. Volcanic eruptions may have caused the Great Dying, which wiped out much of the earth's marine life.
2 Altogether, the five mass extinctions caused 75 percent of the planet’s life to die out. The sixth mass extinction may now be beginning — and we're the cause of this one.
3 Over the last several centuries we have constantly burned fossil fuels, like oil, coal and natural gas. In the process, we've changed the climate for other species. Humans use more than half of the planet’s unfrozen land for cities and logging or food. Our takeover has destroyed the natural habitats of animals and plants.
Evaluating Claims: Mass Extinctions |
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In the first paragraph, the author starts with the word “cataclysmic” to describe the first five mass extinctions. He goes on to state, “Volcanic eruptions may have caused the Great Dying, which wiped out much of the earth's marine life.” These two sentences grab the reader’s attention and remind the reader about the grave impact related to the concept of extinction. |
1. Cataclysmic events drove the first five mass extinctions in Earth’s history. An asteroid ended the age of the dinosaurs. Volcanic eruptions may have caused the Great Dying, which wiped out much of the earth's marine life. |
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In paragraph two, the author makes the unsupported claim (speculation) that humans will be the cause of the 6th mass extinction. The author is drawing a conclusion that will need support that can be validated. Ask yourself:
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2. Altogether, the five mass extinctions caused 75 percent of the planet’s life to die out. The sixth mass extinction may now be beginning — and we're the cause of this one. |
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The third paragraph is essential in that it provides the reasoned judgment to paragraph two. The information in the third paragraph can be validated as to whether or not it is grounded in fact. The author explains how humans’ use of the earth’s resources (burning fossil fuels, logging, building cities) has destroyed animal and plant habitats. The underlined facts provide evidence to support the author’s claim that humans may cause the sixth mass extinction. |
3. Over the last several centuries we have constantly burned fossil fuels, like oil, coal and natural gas. In the process, we've changed the climate for other species. Humans use more than half of the planet’s unfrozen land for cities and logging or food. Our takeover has destroyed the natural habitats of animals and plants. |
As you continue to read scientific texts, evaluate the claims that the author makes by looking at the facts and research findings that the author uses to support such claims. Reasoned judgments are supported with appropriate facts and research. Speculation is an unsupported claim. Being able to distinguish between supported and unsupported claims will allow you to decide what information you will accept from a text, and what information you may need to validate or check in other sources.
Now go to the next page to explore the article further.
