How would you feed you cells if you didn't have a digestive system?
1 Answer
Here's what I get.
Explanation:
A digestive system takes in nutrients, energy, and water and gets rid of waste products.
Humans have evolved an efficient internal digestive and circulatory system that extends to every cell in the body,
If we had no internal digestive system, we would need a different way to take in nutrients and get rid of wastes.
1. The plant option
We might develop roots on our feet that would temporarily dip into the soil to obtain water and nutrients.
We would then have to develop a large surface area (leaves?) and a photosynthesis mechanism to obtain energy from sunlight.
Our mobility would be restricted, and we would look completely different.
2. The fungal option
We might develop methods of absorbing nutrients directly through our cell walls.
Then, we might have to lie around in the soil most of the day to absorb the nutrients.
If we depended on diffusion through cell walls as our source of food, we would be much smaller.
As we get bigger, our outer cells will be unable to keep up with needs of the inner cells.
Eventually, we get so big that our inner cells will die because they can't get nutrients quickly enough.
We can follow the diffusion of
The "nutrients" have diffused all the way to the centre of the smallest cube, but the largest cube is mostly "starved" in the centre.
3. Other options
Who knows? Perhaps we might evolve some other type of digestive system.
Personally, I'm happy with what I have.
