Why have Variation ?

Table of Contents

This game is about Variaiton amongst Rabbits. Change the environment and play around with the settings. See what happens:

Have a play with this Peppered Moths Game: https://askabiologist.asu.edu/games-sims/peppered-moths-game/play.html

Why is Variation Important

Variation is important as it increases the likelihood of the species surviving environmental change

This change can be in the physical environment, it could be due to the arrival of a new species to the environment or it could be due to disease

Giraffes

Millions of years ago, the Savanna of Africa was not there, rather it was Trees and Green

But, then the climate changed, it rained less and the trees started to become fewer and fewer

This made it harder to hide from predators

So, if there was a taller member in the group, they could spot predators sooner and they could run away

Thus the groups with shorter members died out as they were eaten

This pushed the necks longer and longer as those groups that had the tallest members survived the best.

At the same time they could access food that was higher up in the trees that the shorter families could not

Climate change has been a major driver for evolution, including our own

Our ancestors lived with these Giraffes in Africa, living amongst the trees. Climbing in the trees and walking on all fours

Climate change removed the trees, those families that could stand and look around could spot predators faster

This ability to stand and walk on 2 legs favored those that did this most naturally, so this trait was passed on. And who ever did this the best in each generation had the most offspring

The problem with climate change now is that it is happening too fast for organisms to be able to evolve to match it. Evolution requires mutations, then mating, then babies, then one family with the favored mutation slowly spreading and becoming the dominant family until all the subsequent generations are linked back to this one family and the one individual in who's gametic germ cell the mutation occurred. This is a slow process. Evolution is slow. Because of how slow mutation is, thousands of species are predicted to become extinct due to human caused (anthropogenic) climate change

Variation means that should the environment change, maybe due to climate change, maybe due to war, maybe due to disease.... then some of us might have a few traits that allow us to survive, such as a resistance to that disease. Thus the species will not become extinct

Basically, so that the species will survive even if the environment changes

polar bears and grizzlies
kia vs kaka
find the 'life will find away' image from jurassic park

Variation and Natural Selection

Natural selection - starts with variation, followed by selection for favored traits within a population

Those traits come to be the most common, this leads into evolution if the trait becomes spread throughout the whole population or if the population is separated from other related populations due to oceans, mountains, humans etc. Thus you eventually end up with a population that is different from its ancestors - like the Kea and the Kaka

Variation and Evolution

This follows on from Natural Selection

In a particular environment those with particular traits are favored

As the environment changes other traits might be favored

As predators adapt other traits might be favored

Eventually those whos families do not have the favored traits either breed with those that do and thus their descendants will have those traits, or they will die out

Over time, there is a very slow race

The predator adapts to better hunt its prey, the prey adapts to better hide from the predator, so the predator adapts to better hunt its prey, so the prey adapts to better hide... and so on for thousands of years. Driving evolution, you can only pass on your genes if you survive, and survival might be by being the best hunter in your species, or if hunted, then your survival is by being the best at hiding

The better hunter will always kill the worst at hiding, and the worse hunter will starve as those that are hidden are too hard to find

Only the strong predators and the strong prey survive to pass on their traits

Only the strong survive

Only the fittest pass on their genes

And the offspring are those that whose parents survived to a reproductive age

The offspring are the offspring of the winners of life's fight for survival

Click on the following interactive