Selection and Survival Tortoise Lab

Hypothesis:

I think that, over time, there would be more long-neck tortoises, Despite the fact that the long-neck trait is recessive, the short-neck population would start slowly dying out, leaving the heterozygous and homozygous long-necks behind. This could lead to the birth of new short-necks, but they wouldn't survive for very long, because of the lack of food. On the other hand, the homozygous long-necks would live much longer, and reproduce further.

Punnett Squares:

Round 1:

                                                                     

                  Male

NN	nn
NN	nn

                Female

NN	nn
NN	nn

Round 2:

 Round 3:

 

Round 4:

DATA ANALYSIS:  

Looking at the results my group and I acquired over the course of this lab, I can see that, over the course of several generation the tortoises with short necks started diminishing, despite the fact that this trait is dominant. For example, you can clearly see that, in the great grandchildren's generation, or Round 4, there is only two short-necks left, and they are heterozygous, meaning that, despite having a short neck, they still carry the recessive short-neck trait. This is very different compaaring to the results from the generation of children or Round 2,  where there were olny two long-neck tortoises. This data shows that, as time passed, over the course of several generations, the short-neck turtles started dying out, because they couldn't sustain their trait and their species any longer, due to the severe lack of nutrition. However, the long-neck turtles lived on, because they did have food, despite the fact that the trait they carry is recessive.

If none of the long-neck tortoises mated with each other after Round 4, but there was still no food left for the short-necks, I believe that the exactly same situation would occur. At the beginning, there may be more short-necks, but the lack of food would cause their slow downfall, just like it did in the first four generations that we originally tested.

I believe that there is a lack of food for a certain type or sub-type of a species, there is only three things that can occur. If the lack of food is sudden, meaning that it is caused by a natural disaster, such a tsunami or earthquake, the species would probably go extinct, considering the fact that they would literally have no source of nourishment. However, if the food starts decreasing gradually, the species could either start evolving to adapt to the new habitat or environment, or it could start slowly diminishing, the way it did in this lab.