Society of producers, humans who can produce solid material from their bodies and it is used to make clothes, tools and buildings

Question

In this world humans are kind of like spiders: they can produce their own building material.

This substance can be used to make clothing resistant to heat and cold depending on the variation.

It can also be used to make solid structures like walls.

The material consumes human energy and nutrients; if a person produces 1 kilogram of material, they lose roughly 1 kilogram of body weight and they need to get that energy back from food.

The material comes in two variations which can be chosen by the producer.

Heat insulating one that protects you from high heat environments and is strong enough to handle boiling water. If you were to wear a glove made of that material you could touch boiling water and not feel anything.

This variation is comparable to spider silk when it comes to strength, density and other proprieties which dictates how easily it breaks.

The second variety protects from the cold, but doesn't protect from high heat. And it's also comparable to handwavium: incredibly strong but also relatively light. Light enough to make clothes out of it and strong enough to build a bridge with it.

The material comes out of the body directly in the desired shape. If one wants to make a sword or brick, it is easy, but for clothing the producers need to make a wire and then weave it.

How would such ability influence early hominids 2.5 million years ago?

Would it speed or slow development of human intelligence?

Answer 1

The silk-analogue-producing hominids would die out

In its simplest terms, this is an ability that disadvantages early hominids in a kill-or-be-killed world. Compared to a standard model Homo habilis, the brick producers suddenly have a considerable portion of their body converted to silk-analogue-producing glands, probably several different sorts (having read about spider silk). The glands and supporting structure would need to be very large proportional to their body in order to produce bricks, swords and similar sized objects. Adding lots of extra weight which does not assist with its hunter-gatherer activities (see below) reduces survival chances significantly.

Producing silk is a winning strategy for spiders because, while they spend lots of energy building a web they can then (looking at this question on Biology SE) kick back and use extremely little energy while waiting for something to wander into their web.

Mammals in general and big-brained hominids in particular cannot do this - they are constantly burning energy to regulate their body temperature and power their brain. If they need a sharp stick then breaking one off a tree requires a tiny fraction of the energy it would take to extrude one. If they need a sharp rock then they look around until they find one and maybe chip it into shape against another rock.

There is no evidence that Homo habilis wore clothing - given that they survived to evolve into us eventually, they clearly did not need it. If they did need clothing then they could use the aforementioned sharp stick and sharp rock to kill and skin a suitably furry creature for much less energy expenditure than it would take to grow it themselves. Similarly, there is no evidence of control of fire prior to Homo erectus, so the heat-resistant insulating properties of the silk are not applicable to their life.

This is probably the key point - you or I can think of all sorts of cool things to do with our own personal 3D printer. An animal that does not yet even understand how to use fire or furs as clothing simply lacks the knowledge to see the possibilities. They certainly will not have any idea how to turn wire or a thread into woven cloth - that is a very recent invention. If they burn lots of energy producing even one item that does not immediately make it easier to get more food to replace what they have used then they will starve to death.

In summary - this ability would not evolve naturally in early hominids. If the Vorlons visited alternate-Earth and changed the hominids to have this ability, they would need to program them with plans for bows, arrows, knives, ropes, looms etc and instructions for how to use them or the change would simply kill the hominids.

Addendum - spider silk is stable from -40 to 220C. As noted by Joe Bloggs, an insulator slows the transfer of heat in both directions. While I am uncertain of the intent of having two different materials, I suggest that one material is probably sufficient. Produced by a very different species.