1-Natural selection:



is based on differential success in survival and reproduction individuals in a population exhibit variations in their heritable traits, and those with traits that are better suited to their environment tend to produce more offspring than those with traits that are not as well suited. Darwin's grand idea of evolution by natural selection is relatively simple but often misunderstood. To find out how it works, imagine a population of beetles:

There is variation in traits. For example, some beetles are green and some are brown.

There is differential reproduction. Since the environment can't support unlimited population growth, not all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do. 2- Microevolution: change in allele in frequencies population by time.

3- genetic variation: differences among individuals in the composition of their genes or other DNA sequences.