Key Details that Support the Main Idea

Otis and Pearl are trapped in the Jurassic Period. They are researching the topic and looking for the details that will help them escape. Otis and Pearl must locate key details that support the main idea. The main idea is the focus of a text or paragraph. Key details are examples of evidence used to support the main idea. These can be facts or examples to help understand the topic. However, not every idea in a text is relevant to the main idea. Authors usually include interesting details that enhance the text, but do not help with understanding the main idea. For example, if the main idea was describing alligators' eating habits, one key detail would be that they eat once a week. A detail that could be included for interest could be stating that they live for around thirty to fifty years. We can discover the important details that support the main idea by first determining the main idea and then looking for text evidence that is directly connected to the author's point of view. Let's assist Pearl and Otis by reading passages and identifying key details to support main ideas. The Jurassic Period was a period of significant changes for the planet. It lasted slightly more than fifty million years and began approximately two hundred million years ago. Previously, the Earth was a single landmass known as Pangea. Shifting tectonic plates caused the land to fracture and move apart, resulting in the continents we know today. Which of these sentences best describes the author's main idea? A: Millions of years ago, the Earth was one large piece of land. B: Earth's surface went through many changes during the Jurassic Period. C: Shifting tectonic plates caused new lands to form. Looking back at the text, we see that the topic sentence states that the Jurassic Period was a time of significant change for the planet so our answer is B, "Earth's surface underwent many changes during the Jurassic Period." Which key detail from the passage best supports this answer? A: Lasted slightly more than fifty million years. B: The Earth was a single land mass. C: Shifting tectonic plates caused land to fracture and move apart. Choice A is an interesting fact about the Jurassic Period, but does not connect to the idea of changes during this period. Choice B just refers to how the Earth was different, and not what was different; this is known as a distractor. The correct response is C, "shifting tectonic plates caused land to fracture and move apart." Let's try this one. The Allosaurus was a deadly predator during the late Jurassic Period. It was a two-tonne, nearly forty-foot-tall, meat-eating theropod. The dinosaur had three sharp claws and dozens of blade-like, serrated teeth. With its fast speed and axe-like horned head, it ambushed large herbivorous dinosaurs. Some paleontologists believe they hunted in groups, while others think they were scavengers. Which of these sentences best describes the author's main idea? A: The Allosaurus may have hunted in groups. B: The Allosaurus was a theropod. C: The Allosaurus was regarded as one of the most dangerous dinosaurs of its time. Now, look back into the text to find the main idea. The main idea is C. Which key detail from the passage best supports this answer? A: "It was a two-tonne, nearly forty foot tall meat eating theropod." B: "With its fast speed and axe-like horned head, it ambushed large herbivorous dinosaurs." C: "Some palaeontologists believe they hunted in groups..." The key detail is B. Remember, key details are evidence an author uses to support the main idea. We can find the key details that support the main idea by first determining the main idea of a passage and then finding evidence in the text that directly connects to the author’s point of view. Now that Otis and Pearl have learnt about the Jurassic Period it looks like they have decided to stick around for a bit.