The body senses that it's cold, and the brain thinks how is it going to make the body warmer?
Keith S. Taber
Bert was a participant in the Understanding Science Project. In Y11 he reported that he had been studying about the environment in biology, and done some work on adaptation. he gave a number of examples of how animals were adapted to their environment. One of these examples was the polar bear.
…our homework we did about adapting, like how polar bears adapt to their environments, and camels….
And so a polar bear has adapted to the environment?
Yeah.
So how has a polar bear adapted to the environment?
Erm, things like it has white fur for camouflage so the prey don't see it coming up. Large feet to spread out its weight when it's going over like ice. Yeah, thick fur to keep the body heat insulated.
Bert gave a number of other examples, including dogs that were bred with particular characteristics, although he explained this in terms of inheritance of acquired characteristics: suggesting that dogs that have been taught over and over to retrieve have puppies that automatically have already got that sense. Bert realised that this example was due to the work of human breeders, and took the polar bear as an example of a creature that had adapted to its environment.
Yeah, so how does adaption take place then? You've got a number of examples there, bears and dogs and camels and people. So how does adaption take place?
I don't know. It may have something to do with negative feedback.
That's impressive.
Like you have like, you always get like, you always get feedback, like in the body to release less insulin and stuff like that. So in time people like or whatever, organisms, learn to adapt to that. Because if it happens a lot that makes a feedback then it comes, yeah then they just learn to do that.
Okay. Give me an example of that. I'm trying to link it up in my head.
Okay, like the polar bear, like I don't know. It may have started off just like every other bear, but because it was put in that environment, like all the time the body was telling it to grow more fur and things like that, because it was so cold. So after a while it just adapted to, you know, always having fur instead of, you know, like dogs shed hair in the summer and stuff. But like if it was always then they'd just learn to keep shedding that hair.
So if it was an ordinary bear, not a polar bear, and you stuck it in the Arctic, it would get cold?
Yeah.
But you say the body tells it to grow more fur?
Erm, yeah.
How does that work?
I'm not sure, it just … I don't know. Like, erm, like the body senses that it's cold, it goes to the brain, and the brain thinks, well how is it going to go against that, you know, make the body warmer. And so it kind of, you know, it gives these things.
Is that an example of feedback?
Yes.
So Bert seemed to have notion of (it not the term) homoeostasis, that allowed control of such things as levels of insulin. He recognised thus was based on negative feedback – when some problematic condition was recognised (e.g. being too cold) this would trigger a response (e.g., more insulation)to bring about a countering change.
However, in Bert's model, the mechanism was not automatic. Rather it depended upon conscious deliberation: "the brain thinks, well how is it going to …make the body warmer". Bert thought that this process which initially was based on deliberation then became automatic over many generations.
This seems to assume that bears think in similar terms to humans, that they identify a problem and reason a way through. This might be considered an example of anthropomorphism, something that is very common in student (indeed human) thinking. To what extent it may be reasonable to assign this kind of conscious reasoning to bears is an open question.
However there was a flaws in the process described by Bert that he might have spotted himself. This model suggested that once the bear had become aware of the issue, and the needs to address, it would be able to grow its fur accordingly. That is, as a matter of will. Bert would have been aware that he is able to control some aspects of his body voluntarily (e.g., to raise his arm), but he cannot will his hair to grow at a different rate.
Of course, it may be countered that I am guilty of a kind of anthropomorphism-in-reverse: Bert is not a bear, but rather a human who does not need to control hair growth according to environment. So, just because Bert cannot consciously control his own hair growth, this need not imply the same is true for a bear. However, Bert also used the example of insulin levels, very relevant to humans, and he would presumably be aware that insulin release is controlled in his own body without his conscious intervention.
As often happens in interviewing students (or human conversations more generally) time to reflect on the exchange raises ideas one did not consider at the time, that one would like to be able to to text out by asking further questions. If things that were once deliberate become instinctive over time, then it is not unreasonable in principle to suggest things that are automatic now (adjusting insulin levels to control blood glucose levels) may have once been deliberate.
After all, people can control insulin levels to some extent by choosing to eat a different diet. And indeed people can learn biofeedback relaxation techniques that can have an effect on such variables as blood pressure, and some diabetics have used such techniques to reduce their need for medical insulin. So, did Bert think that people had once consciously controlled insulin levels, but over generations this has become automatic?
In some ways this does not seem a very likely or promising idea – but that is a judgement made from a reasonably high level of science knowledge. It is important to encourage students to use their imaginations and suggest ideas as that is an important aspect of how science woks. Most scientific conjectures are ultimately wrong, but they may still be useful tools for moving science on. In the same way, learners' flawed ideas, if explored carefully, may often be useful tools for learning. At the time of the interview, I felt Bert had not really thought his scheme through. That may well have been so, but there may have been more coherence and reflection behind his comments than I realised at the time.
