1. Genetic Variation- Giraffes with longer necks are born, the genetic variation includes giraffes with different lengths of a neck.
2. Overproduction of offspring/ struggle- The struggle for survival in this case would be which giraffes have the longest neck, allowing it to reach its food source. The giraffes that are most fit will eat and survive. The giraffe will get the length of its neck from the genes passed on by its parents.
3. Differential Survival and Reproduction- Throughout many generations, giraffes with longer necks have reproduced the most, therefore inheriting its traits onto their offspring. These giraffes were able to pass on its genes because it survived long enough to reproduce.
4. Change in the Gene Pool- As generations have passed only the giraffes with long necks have reproduced, the genetic gene pool is now filled with long neck genes. The only kind of neck giraffes will have is a long neck that can reach the tops of many trees. These traits have been passed down by giraffes that also have a long neck. The gene pool has adapted to the more beneficial trait of a long neck.
In this example of natural selection, the dark orange represents short giraffes while the light orange represents tall giraffes.