Question

Red beetles live in bush with green beetles. Eventually, the number of green beetles increases as compared to the red beetles. Give reasons

Answer 1

It's because the green beetles show the property of camouflage which makes it difficult for predators to find them, while red beetles can be spotted easily.

Answer 2

The above question is an excellent example for Charles Darwins theory of natural selection.

When red beetles and green beetles thrive in a bush (which is green in colour) they must be able to camouflage (merge with the surroundings) in order to escape from predators. Most predators (like birds or lizards) can easily spot the red beetles and feed on them. It’s quite difficult to spot the green beetle in bush.

Hence the predators eliminate most of the red beetle population and eventually the number of green beetles are greater than the red beetles.

Thus, nature selects one trait (green colour) and renders the other trait (red colour) unfavourable.

It is also interesting to know about the evolution white and black coloured peppered moth in UK that resides at tree bark, a case of industrial melanism. Due to advent of industrial revolution in 1800s, dark smoke settled on the tree barks. This helped black peppered moth to camouflage easily but the white peppered moths suffered from predation. Eventually the number of white peppered moths declined.