Natural selection. Natural selection is the survival and subsequent reproduction of those individuals that are best adapted to live in there environment. Put the following statements into the correct order to describe the sequence of events that take place during natural selection.

The stages of natural selection. Variation in the population. Environment changes. Particular characteristic gives some individuals an advantage to survive. These individuals have more babies than others over their life. The gene that gives these individuals an advantage is passed onto the next generation, and becomes more common.

Rabbits. A. Short eared rabbits have most babies and pass on the genes for short ears to their babies. B. The rabbits move into a new area of grassing which is colder. In cold conditions, long ears lose more heat than short ears. C. Rabbits have in their population a degree of variation in ear length. D. Over time the whole population gets shorter ears. E. All animals over-produce. Those rabbits with short ears lose least heat and find it easier to survive and so have babies.

Peppered moths. A. Pollution of towns in Britain leads to the blackening of tree trunks by soot. Black moths were spotted less easily than mottled grey moths by birds. B. More black moths survived to sexual maturity than mottled grey moths. C. As most moths that are breeding are black over time most moths in the population are black. D. Peppered moths are a mottled grey colour that gives them good camouflage against the bark of trees, so preventing them being eaten by birds. Some peppered moths are black and they tend to be easterly spotted by birds and are eaten in areas that are not polluted. E. Black moths passed on the genes for black bodies to their offspring.

Hedgehogs. A. Hedgehogs (are nocturnal) live infields and woods and when scared most role up into a ball with their spines pointing out for protection, a few try to run away from predators which is not usually a good idea. B. Over several generations a greater number of the population of hedgehogs have improved road safety. C. Over time due to the overproduction of offspring a greater number of babies were born to hedgehogs that don’t role up when they see car head lights. D. When cars became common lots of hedgehogs when caught in the headlights of cars rolled up and were squashed. Those hedgehogs that tend to run from predators tended to keep moving when cars went past and less of these were killed. E. The genes that control the behaviour of hedgehogs, not to roll up when car head lights are seen, are passed on at a greater frequency (amount) than those genes that encourage the rolling in the presence of head lights.

Now make up your own example of natural selection up. Remember what happens to the age that fish become sexually mature in areas of over fishing. Why did Giraffes necks get longer? Remember Darwin’s finches and beak size. Why did head lice become resistant to pesticide.