You are studying a large tropical reptile that has a high and relatively stable body temperature. How do you determine whether this animal is an endotherm or an ectotherm? a. You know from its high and stable body temperature that it must be an endotherm. b. You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm. c. You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm. d. You measure the metabolic rate of the reptile, and because it is higher than that of a related species that lives in temperate forests, you conclude that this reptile is an endotherm and its relative is an ectotherm.

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Hi everyone. Our next question says, I suppose you want to identify whether an animal we found in the forest is ecto therm or endo therm. Which of the following variables can you use to answer your query. So let's just quickly recall from our content videos ecto therm versus end of term. So what we need to do, distinguish between them. Well, Ecto Therms depend on external heat to maintain their body temperature as a result their body temperature changes with changes and external temperature. Endo Therms depend on their internal heat produced by their body to maintain their body temperature and that's regardless of the external temperature. So that means their body temperature does not change with changes and the external temperature. So we know from this that the two things we want to be looking at to determine the difference are the environmental temperature and their body temperature whether that body temperature is changing with the external temperature or not. So first, let's look over our answer choices. We can eliminate anything that doesn't have those two things as variables. Environmental temperature and body temperature. So keeping that in mind, let's look at choice A. Well, it has environmental temperature and body temperature. Choice B. Has environmental temperature. But then the other variable they use is growth. So we know we can eliminate choice B. Choice C. Has environmental temperature and body temperature. Choice D. Has metabolism rate and environmental temperature. So we know that we can eliminate choice D. As well. So we're down to two choices whether which one environmental body will have is the dependent variable independent well, the independent variable is the one that we're going to change and based on those changes, the dependent variable we would expect to respond to that and we would look at how it's related. So in this case since we're thinking about will body temperature change as a result of changes in the external temperature than the external temperature? It's a different color. The external temperature will be our independent variable. We're going to set that at a certain level and then change it and see what happens to the variable that's dependent on that. So we want the external temperature to be the independent variable and then the body temperature To be the dependent one. So when we see that choice A says environmental temperature is dependent so we can eliminate choice A. That is not correct. So the correct answer is choice C. Environmental temperature as the independent variable and body temperature as the dependent variable. Thanks for watching, we'll see you in the next video.

Verified Solution

Key Concepts

Endothermy vs. Ectothermy

Metabolic Rate

Thermal Environment