Explain the idea of natural selection and how it leads to changes in a population.?

Question

Explain the idea of natural selection and how it leads to changes in a population.

Answer 1

Let's say for instance that on a species that due to genetics, every so often a darker ladybug is produced. Those darker ladybugs aren't as easily seen by birds so they don't get eaten as often and therefore a greater percentage of them live to an age where they can reproduce. Even if the darker ladybugs breed with the lighter colored ladybug, over time they will catch up and eventually overtake the population of their lighter colored relative.

For example:

100 dark ladybugs and 75% live to reproductive age and each bug that reaches reproductive age produces 10 baby ladybugs a year

1,000 dark ladybugs and 25% live to reproductive age and each pair that reach reproductive age produces 20 baby bugs a year

100 x 75% = 75 bugs x 10 = 750 dark ladybugs (year 1)
750 x 75% = 563 bugs x 10 = 5,630 dark ladybugs (year 2)
5,630 x 75% = 4,223 x 10 = 42,230 dark ladybugs (year 3)

1,000 x 25% = 25 bugs x 10 = 2,500 light ladybugs (year 1)
2,500 x 25% = 625 bugs x 10 = 6,250 light ladybugs (year 2)
6,250 x 25% = 1,563 bugs x 10 = 15,630 light ladybugs (year 3)

Using the example above, by the end of year 3, the dark ladybugs will outnumber the light ladybugs.

The survivability is a little exaggerated compared to real life to get the point across. Normally the effect is more gradual and takes a longer amount of time for the effects to be seen.

The natural selection part would be due to the darker color the darker ladybugs don't get eaten and more of them live to an age where they can reproduce.

Answer 2

Natural selection is the process where populations may increase if they aquire genetically beneficial characteristics. They may decrease if other populations gain characteristics which give them an advantage.

Answer 3

This is clearly straight from an exam paper. You could have at least put it in your own words, dude.