The four key points of Darwin's evolution theory are the following:
-Variation in populations
Individuals of a determined species are not equal, there are small variations between individuals, even if they are related. They may vary in color, size, weight, and other characteristics. This happens because even individuals from the same species have different genetic makeups.
-Inherited traits
Every species has determined traits that are inherited. These traits are passed from parents to offspring and those who help improve the odds of survival are more likely to be passed to the subsequent generations (adaptation)
Only traits that are genetically encoded can be inherited to the next generations, those who are developed through environmental factors are not inherited.
-Selection
Some individuals have inherited characteristics that help them survive and produce offspring. For example, individuals with colors that allow them to camouflage and avoid predators are more likely to survive and reproduce than those that do not have camouflage. As a result, the genes of the individuals with better odds of survival will become more common in the population.
-Time
Over time, selection produces changes within the species, usually, these changes are not observed until many generations have passed and are the result of successful variations accumulated through time.
Breeders know that if they breed certain pigeons, their offspring will show the traits they are interested in, which means that the offspring will inherit the traits from their parents. This scenario follows the inheritance of traits observation.