Natural Selection

Genotype- the gene sequence that an organism inherits from its parents.
Phenotype- the characteristics an organism shows as a result of their genes.

There is a dominant and a recessive allele. The dominant allele will determine the phenotype whenever it appears. The recessive allele will show if it is the only allele in the genotype.

In the case of Bengal Tigers, a recessive phenotype means no fur. And no fur means death in the winters. So we did an experiment on natural selection's effects on a gene pool. We used colored beads to represent alleles, and picked them two at a time randomly out of a bag.
Each time we got a recessive phenotype, those bead alleles were eliminated. Eventually after about 6 generations of random breeding, the recessive phenotype stopped occurring, thought the recessive alleles remained in the gene pool.

Natural selection is the process of eliminating those traits that do not help survival. Evolution operates on populations over time, not individuals. Individuals just die and fail to pass on their genes.