Can you guys find us some food today? We can’t run that fast, and we are very hungry.
What a nice day in Monkeytown! I can’t wait to go hunting!
Uh oh! Please move out of the way, we have to get out of here.
Oh no! The volcano is erupting, we have to get out of here.
There is a fire! Those stronger monkeys are too fast! We have to flee!
Let’s go, let’s go. I think we’ll make it out in time, we are fast enough!
In a village called Monkeytown, there is a very large active volcano, as well as 10 monkeys. 5 of the monkeys have long legs, and are more muscular (lighter shade). 5 of the other monkeys have shorter legs and are not as muscular (darker shade). The monkeys with the stronger legs have the adaptation of longer legs.
Ahhh! The fire is on top of us! I wish we had stronger legs!
We’re almost there guys! Our strong leg adaptation helped us to get out in time.
In Monkeytown, the volcano erupts! However, when the monkeys try to run away, there is a large boulder that blocks the west exit of the volcano. Thus, all of the monkeys have to flee through the east side of the volcano. In this scenario, the volcanic eruption is the survival pressure.
Ahh, death has consumed us...
Phew, we made it! Our long legs really helped us to make it out in time. RIP smaller monkeys.
As the lava flows from the volcano, all of the monkeys have to flee through the east side of the volcano. This is known as the Bottleneck Effect, where a disaster reduces the population. All of the monkeys with the stronger legs are going to have a selective advantage, as they can run faster than the the others, and escape.
Now that we all have strong legs, we can pass this trait on to our children. I’m glad we made it out alive!
As the fire from the volcano expands, some of the slower and weaker monkeys get caught in the fire, while the monkeys with stronger legs escape the fire and lava. This is natural selection, or survival of the fittest, as the monkeys with the strongest legs escape the fire, while the weaker ones do not.
The monkeys with the weaker legs die from the fire, while the monkeys with the stronger and longer legs are able to escape. The monkeys with stronger legs wait for the volcano to cool down, and then migrate back to their original home.
Since all of the surviving monkeys have the trait of strong legs, reproduction between these monkeys will lead to descent of modification, or passing down the trait of long legs to the future generation. This favorable adaptation will be passed down to the future generations due to the reproduction of this population.