The most logical answer that I can think from Darwin's Theory of Evolution is that that species had been isolated from other possible panthers to mate with. So after generations of that isolated group of panthers their offspring would eventually become increasingly similar.
The factor that poses the greatest threat is loss of habitat. Have a nice day!
Answer:
They would freeze and it would be hard to find food because they are not accustomed to the different climate. They would also be easy prey because of the environment change they are not equipped for.
The independent assortment of genes is a principle of Mendel and of genetics. Since humans are diploid organisms (they have 2 copies of their genetic information), we have that each gamete carries one of the two available alleles for each feature. These gametes are created in equal proportions.
We have that both parents are heterozygous for a feature, lets say H. Thus, their genotype is Hh. Hence, the child will get with probability 50%=1/2 H from the father and 50%=1/2 h from the father; same from the mother. By doing a Punnett square, we get that there is 1/4 chance that the child is HH, 1/2 chance that it is Hh and 1/4 that is hh. Since the disease is recessive (so both alleles are needed), we have that the chance that the kid has the disease is 1/4.