Category: Science

All populations have a limit

“All populations have a limit” means that a population can’t continue to grow to infinity. This is because of space, food, housing, money, and everything else that it takes to keep a population healthy and strong.

On the bottom of the graph above, there are numbers which indicate time. It started at 500 BCE to 2025 CE.  On the other side it has numbers of how many people there are in the world. If it continues to increase at the same rate, then there would be too many people and not enough room, which means that there would not be enough food, jobs, housing or money.

If this was a shark population, then the sharks would starve to death. In the experiment we did, if sharks didn’t eat enough minnows, then they would become extinct. Well guess what, that is the same thing that could happen to humans: we will not survive much longer if the population is still going to keep on growing. We have to have a plan.

One idea that might work is that we only allow one kid per family, or we just keep it how it is now and hope for the best. Whatever we do, we will have to figure it out soon. Or else future generations will all die.

Shark Tank Simulation

We did an experiment in science where we went outside and played a simulation. It was a game where there were one shark and four minnows and the rest of the class were seaweed. To survive, the shark has to eat two minnows, and to reproduce, it has to eat  four minnows. The minnows have to eat one seaweed to survive and two seaweed to reproduce.

The first trial was really bad because we had no strategy. The shark died in the first round, same with one minnow. Then two of the three minnows ate way too much. They ate 9 seaweed each, which meant there were a lot more minnows then seaweed. Which meant that in a few rounds, the seaweed would be gone, which meant the minnows have nothing to eat which meant they go extinct.

The top image below shows the line graph of the bad run.

Then we figured out a strategy where the shark only ate 2 minnows and the minnows only ate 2 seaweed. We kept on doing that and we did really well. We ended with over 90 seaweed and 2 sharks and 8 minnows. We could do that forever and have over 1000 of each thing.

The bottom image below shows the line graph of the good run.

This teaches us that it is important to for each species to have enough to eat, and have a good balance between the numbers of them. That way, the cycle can just keep going without one of the species going extinct.