A scientific and valid explanation of evolution was first proposed by Charles Darwin and Alfred Wallace in 1859. Over time, this theory has been refined with advancements in the field of genetics, resulting in what is now known as Neo-Darwinism.

The main features of Neo-Darwinism are as follows:

1. Overproduction of Offspring:
   All organisms tend to produce more offspring than the environment can support. However, not all survive due to limited resources.
2. Genetic Variation: Mutations, which are changes in the DNA due to replication errors, introduce new genes into a population. In sexually reproducing organisms, processes such as meiosis and fertilization result in genetic recombination, leading to variations among individuals. These variations are often heritable and are the basis of evolutionary change.
3. Natural Selection: As proposed by Darwin, natural selection acts on these variations. Traits (or genes) that enhance an organism’s ability to adapt and survive in its environment are more likely to be passed on to the next generation.
4. Survival and Reproduction: Offspring that possess favorable adaptations have a higher chance of surviving, reaching reproductive age, and transmitting their advantageous traits to their offspring.
5. Outcome of Evolution: Over time, the process of evolution leads to better adaptation of organisms to their environment and contributes to the diversity of life forms found on Earth.