Hey! I'm Shelly and my mate's name is Neil. We will be demonstrating the act of Natural Selection in our own environment.
In our environment, some of our offspring are less likely to survive and reproduce because they don't have traits to survive in this environment. So, Neil and I have more offspring naturally so that more are likely to survive and reproduce and keep our species of snail alive.
Because of our natural differences, Neil and I's offspring are all genetically different. All of our babies have different combinations of our traits. Some of them, however, are more likely to survive in our environment.
As you may be able to tell, Neil's shell blends in with the mud more than mine does. This also means that the offspring with my traits are not able to blend in with our environment. Unfortunately, this means that the snails with yellow shells are more likely to be picked out by our predators.
In conclusion, Natural Selection is when animals breed with their same species and the ones with advantageous traits are more likely to survive and successfully reproduce.
Over time, the dark shelled snails that blend in with the mud will survive and reproduce, making the population of the dark shelled snails increase. The snails that didn't blend in were likely to die and the total population decreased.