In order for a population to increase the necessary traits are: size and shape. This traits are passed to the offspring. An individual with certain characteristics have the opportunity to produce more offsprings rather than not having those certain characteristics.
Every offspring is born with different characteristics that is inherit from their parents. Their may be some that look very similar, but their are others that look very different. Every specie has different characteristics. For example their a mother goose may have 4 offsprings one of them can come out a different color.
Competition Between Species...
Competition is consider to be a negative interaction between species when they need the same limited resource. Species need this resources in order to grow, survive and reproduce. For example, in Hawaii the state bird called the Nene bird is in danger because the mongoose bird was introduced to their habitat to control rats in sugar canes. However, the mongoose hunts in the day while they are eating resources that the Nene bird needs and they are also eating their eggs, which is preventing the population of the Nene bird to grow.
Some organisms need to have some characteristics in order to survive in a certain habitat. It is more likely that species born in natural selection are the ones who are going to survive the most. In every generation, species are born with different traits.
Natural Selection: The differential survival of organisms. The change in heritable traits over time.
Cronin, J., & Walter, C. P. (n.d.). Competition. Retrieved April 06, 2016, from http://www.biologyreference.com/Ce-Co/Competition.html
Natural and Human Impacts on Wildlife. (2016). Retrieved April 06, 2016, from http://www.nhptv.org/natureworks/nwep16b.htm
The individual organisms that make up a population vary - BIOSC - 0160. (n.d.). Retrieved April 06, 2016, from https://www.coursehero.com/file/p3fdmvo/1-The-individual-organisms-that-make-up-a-population-vary-in-the-traits-they/