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Current time:0:00Total duration:9:16

Worked example: Science passage, part 2

Video transcript

- [Instructor] Now that we've read the passage, let's see if we can answer some questions around it. So question number one. The passage most strongly suggests that Adelita used which of the following to navigate her 9,000-mile journey? So we remember that, if I remember correctly, the passage started with Adelita. Adelita was this turtle, and this 9,000-mile journey was across the Pacific Ocean, from Mexico, from the west coast of Mexico to Japan. So let's see what they're talking about. So the current of the North Atlantic gyre, or gyre, gyre, well, she couldn't have used the North Atlantic gyre. They do talk about that later on in the passage, as a way that turtles in the Atlantic navigate across the Atlantic, but Adelita, the what the passage started with, she was navigating across the Pacific. So she's not gonna be using the current of the North Atlantic gyre. Cues from electromagnetic coils designed by Putnam and Lohmann. Well, they definitely talk about electromagnetic coils designed by Putnam and Lohmann in the passage, and these researchers use those coils to test whether turtles respond to it, that it affects their sense of direction. But Adelita didn't use the cues from electromagnetic coils. It's not like Putnam and Lohmann were on a boat for 9,000 miles with kind of electromagnetic coils near Adelita, and using that to tell Adelita how does she navigate her 9,000-mile journey. It's not like she had access to these things. She did it on her own. The inclination and intensity of Earth's magnetic field. Well yeah, well that's all the whole passage is about. It kind of starts off with, "Isn't it amazing "that this turtle can navigate this 9,000-mile journey "on its own, without some type of a GPS device?" And then it uses the research of Putnam and Lohmann to show that turtles are able to do this by using the inclination and intensity of Earth's magnetic field. So that looks right. Now let's look at the last choice. A simulated "magnetic signature" configured by Lohmann. Well once again, this is like choice B. Adelita did not have access to technology from the researcher or Lohmann, so this is, she was off by herself in the Pacific. All right, number two. Which choice provides the best evidence for the answer to the previous question? So once again, the answer to the previous question is that turtles use the inclination and intensity of Earth's magnetic field. So what's the best evidence for us to feel good about that? That turtles actually do use the inclination and intensity of Earth's magnetic field, to navigate across the Pacific, or to navigate across an ocean? So let's see, lines one through three, starting "In 1996". Let's see, lines one through three. So this is line one right over here, they give us every fifth line. "In 1996, a loggerhead turtle called Adelita "swam across 9,000 miles from Mexico to Japan, "crossing the entire Pacific on her way." Yeah, well this is what they started off with, it was an amazing statement. This was kind of, starts to serve the problems, we're like, isn't this amazing? But how does this happen? This doesn't give evidence or explain why or how they use the inclination and intensity. So let me scroll back. That doesn't give evidence that they use the inclination and intensity of Earth's magnetic field. So I'm gonna cross that one out. Lines 30 to 32, starting with "Using" and ending with "surface". Let's see, lines 30 to 32. Let's see, lines 30 to 32. "Using his coil-surrounded tank, "Lohmann could mimic the magnetic field "at different parts of the Earth's surface." Well, we later do use this, you know, they, Lohmann uses this technology that he's developed to test whether turtles respond, but this sentence by itself isn't providing evidence. It's just starting to say that, hey, Lohmann can mimic magnetic fields at different parts of the Earth's surface. So I don't think that this is, I don't think this is evidence either. And I'm sorry I have to kind of keep scrolling back and forth like this. Lines 53 to 55, "In the wild, stars". Let's see. 53 to 55. 53 to 55. So let's see, that's this right over here. "In the wild, they might well also use other landmarks "like the position of the sea, sun and stars." Well, if we remember, this is when they said look, the turtles use the magnetic field, and they might also use this other stuff. Like, you know, the stars, the position of the sea, sun and stars might also help them. But once again, this isn't evidence for us believing that they use Earth's magnetic field. This is just, these are just other things that they might use. So let me just cross that one out. So, deductive reasoning, it's probably gonna be D, but let's check it out. Lines 64 to 67, starting with "Neither". Lines 64, 64 to 67. Starting with "Neither", so that's right near the end. "Neither corresponds directly "to latitude or longitude," and when they're saying "neither", they're talking about, "Different parts of the world "have unique combinations of these two variables." And those two variables are the intensity, the intensity of the magnetic field, and the angle in that magnetic field. So, "Neither corresponds directly "to either latitude or longitude," And when they're saying "neither", they're saying neither the intensity nor the angle, "but together, they provide a 'magnetic signature' "that tells the turtle where it is." So this is the closest that I would say to actually providing evidence that turtles, that the angle and intensity of a magnetic field can provide a signature to turtles to tell them, to tell them where they are. So I like that one. It's actually the best of all of these, so I would go with D. As used in line three, "tracked" most nearly means. All right, let's check out line three. As used in line three, so, "In 1996, a loggerhead turtle named Adelita "swam across 9,000 miles from Mexico to Japan, "crossing the entire Pacific on her way. "Wallace J. Nichols tracked this epic journey "with a satellite tag." So he put a tag on this turtle and then was able to track it. So let's see. Tracked, as "tracked" most nearly means followed. Followed, not hunted. He's not trying to kill the turtles or anything. It's not like he's traveling over the turtle, and it's not like he's, he's not searching for the turtles, he actually knows where the turtle is because he has this satellite tag on it. So he followed the turtle. All right. Based on the passage, which choice best describe the relationship between Putnam's and Lohmann's research? Well, they seem to validate each other. They were both working on magnetic fields, and how magnetic fields can be used by turtles to navigate. So the first one says Putnam research contradicts Lohmann's. No, that's not, that's not the case. Putnam's research builds on Lohmann's. So this one, this one seems interesting. Let's actually, I'm gonna go back to the passage to make sure that it was Putnam building on Lohmann, versus Lohmann building on Putnam. Lohmann's research confirms Putnam, this could be interesting as well. Lohmann's research corrects Putnam's, no, they, it wasn't like the passage said that Putnam's research was wrong. So we could rule these two out. But let's revisit the passage a little bit, just so that we can make sure we understand the work. So they told us, "How did she," Adelita, "steer across two oceans to find her destination?" It says, "Putnam has the answer. "By testing hatchling turtles in a special tank, "he has found that they can use the Earth's magnetic field "as their own Global Positioning System. "By sensing the field, they can work out "both latitude and longitude "and head in the right direction." And then, "Putnam works in the lab of Ken Lohmann," so Ken Lohmann is his advisor. He's his mentor. So I'm starting to feel that he probably built on the work of Ken Lohmann. Who has been, 'cause "Lohmann has been studying "the magnetic abilities of loggerheads for over 20 years." So Putnam is a junior researcher. So I think it, he's building on the work. He's building on the work of Lohmann. He works in Lohmann's lab. Lohmann's been doing this for 20 years. The author refers to reed warblers and sparrows in line 49 primarily to, so let's see where they do that. Line 49, reed, so let's see. "Before now, we knew that several animal migrants, "from loggerheads to reed warblers to sparrows, "had some way of working out longitude, "but no one knew how." All right, so they're giving these other examples to say hey look, turtles are not the only ones that have this mysterious ability. So contrast the loggerhead turtle's migration patterns with those of other species, no, that's not what they're trying to do. Provide examples of species that share one of the loggerhead's turtle's abilities, yeah, this is feeling pretty good. Suggest that most animal species possess some ability to navigate long distances. No, they're not saying most animals, they're just saying that there's some other species that have this amazing ability. So they're not saying that most species, let me just cross it out like this. Illustrate some ways in which the ability to navigate long distances can help species. No, they're not saying that the reed warbler or the sparrow, because they can travel a long distance, are able to this or that, or find more food, they're just saying hey, turtles are not the only one, there's other species that also can do this. So I'll cross that out. And I'd go with B.