Table of Contents
Do the children have the same shell thicknesses as the parent are the snails identical within each pair before?
No, there was not a change in the distribution or shell thickness. this is because there was no variation in thickness at the start and the snails reproduce by cloning / asexual reproduction.
What drove the evolution of thicker shells in the snail population?
Not based on a need, just the result of predator preferences of thin-shelled snails were removed creating a shift in individuals left to reproduce in the population to be thick-shelled.
Do you think this population of snails will evolve as predators start eating them why or why not?
Will the population of snails with no variation in shells evolve as predators start eating them? No, because none of the snails have the trait for thicker shells. There was no variation in shell thickness, so there were no snails that were easier or harder to eat.
How is the color of a snail shell related to its ability to tolerate high temperatures?
Lighter coloured shells (either due to lighter background or fewer bands) have a higher albedo and absorb less heat from the sun, which allows the snails to maintain a lower body temperature.
Can a snail survive without its shell?
If this shell becomes significantly broken then the snail will probably die. Whilst snails can repair small cracks and holes in their shells, if the break is serious then they will struggle to survive as the shell not only provides protection but also prevents them from drying out.
Can you think of two more ways the snail can use his shell?
The shell has previously just been seen as a way to protect snails from extreme temperatures and from predators. Now we know it also offers defence against nematodes. These parasites are also incredibly numerous.
What is the Darwinian snails lab?
Natural Selection: Darwinian Snails Overview The Darwinian Snails lab introduces students to Darwin’s theory of evolution by natural selection. This lab is based on the work of biologist Robin Seeley (1986) and simulates the evolution of shell thickness in a population of flat periwinkle snails under predation by the European green crab.
Why did the snail population evolve to only have thick-shelled snails?
The population should now only have thick-shelled snails. Why did the population evolve? Because the crabs preferred thinner-shelled snails, only thicker-shelled snails survived to reproduce. Q.3.1. Is there any variation in shell thickness among the snails now? No Q3.3.
Was Robin Seeley’s prediction about periwinkle snails supported by data?
Robin Seeley predicted that she would see evidence for change in periwinkle snails thickness after the green crab arrived. Was her prediction supported by the data? Yes, her prediction is supported by the data.
Are the proportions of snails in the histogram similar to sample?
Are the proportions of snails with different shell thicknesses in the histogram similar to the sample of snails you examined on the previous page? Yes, the histogram reflects my sample. Q2.3.