Why are they different?

For today's class, we did an interesting activity. The whole class divided into groups of two. Each group had a bag of shells. These shells were all collected from the same sea area. Task for each group was to differentiate these shells by various characters, such as patterns, colors and so on. For first round, Jasmine and I put shells into different groups based on their patterns.Whether the lines on the shells were vertical or horizontal. For second round, we differentiated the shells by colors. Some of them were whitish pink, some of them were dull brown. For the last round, we divided the shells into different groups based on size.

Furthermore, we realized that about 70% of these shells had holes on them. These holes indicated that animals lived inside the shells were attacked by other organisms outside of the shells, which could use their tongues as drills to dig holes on the shells. Thus, the shells were empty. Nonetheless, difference in shells was not an evidence of evolution. It was more like a result of mutation. Based on different environment, physical appearances of shells would alter. Due to mutation, shells were able to pass down thes genes that helped them to survive and reproduce.

For further learning, we did a lab by comparing what percentage of salt in water would affect the growth of brane shrimp eggs.

Vertical line pattern

Spiral

Bigger size

MORE SHELLS!