TITLE: The Concept of Homeostasis in Biology

Reading passage

Homeostasis is a fundamental concept in biology that refers to the ability of an organism or a cell to maintain a stable internal environment despite changes in external conditions. This process is crucial for the survival of living organisms, as it ensures that essential parameters such as temperature, pH, and electrolyte balance remain within narrow limits. Homeostasis involves various feedback systems that detect deviations from a set point and initiate responses to correct them. These systems can be found across different levels of biological organization, from single cells to entire ecosystems.

Listening transcript

Alright, class, today we're talking about homeostasis. You might think of it like a thermostat in your house. When the temperature drops below a certain point, the heating kicks in to bring it back up. Similarly, our bodies have systems to keep things balanced. For example, when you exercise, your body temperature rises. To cool down, you start sweating, and this evaporation helps lower your body temperature back to normal. That's homeostasis in action!

Another example is blood sugar regulation. After you eat, your blood sugar levels rise. In response, your pancreas releases insulin, which helps cells absorb sugar and brings levels back down. If blood sugar gets too low, another hormone, glucagon, is released to increase sugar levels. These processes constantly adjust to maintain balance, which is key to our health.

Speaking task instruction

Explain the concept from the reading and use the professor’s examples to show how it works. Preparation time: 30 seconds, Response time: 60 seconds.

Sample student response

Homeostasis is the process by which organisms maintain a stable internal environment, as explained in the reading passage. The professor gave two examples of this concept. First, when we exercise and our body temperature rises, we sweat to cool down through evaporation, which stabilizes our temperature. Second, he talked about blood sugar regulation. After eating, insulin helps lower high blood sugar, and when it's too low, glucagon raises it. These examples show how homeostasis uses feedback systems to keep our body’s conditions constant, which is essential for our survival and health.