Evolutionary Biology: Snail Shell Thickness

Questions and Answers

What would happen if there were no variability in shell thickness?

There would not be a change in the distribution of shell thickness.

What would happen if shell thickness was not heritable?

The children would not have the same shell thickness as their parents.

Would the distribution of shell thickness in the population change over several snail generations if thickness is not heritable?

True

If survival is not selective (shell thickness does not matter), what will happen?

Any snail will get eaten, because their shells protect them equally. Signup and view all the answers

When mutations occur, do the children look identical to each other and their parents, or are there cases where one child is different?

Majority of the children are identical, but some are different. Signup and view all the answers

If a mutation occurred, is it more towards thick-shelled or thin-shelled snails or is it equally likely to happen to either?

Equally likely. Signup and view all the answers

Did individual snails ever change their shell thickness or color?

False Signup and view all the answers

What role did the predators play in causing the population of snails to evolve?

The predators determined which snails survived to reproduce. Signup and view all the answers

Study Notes

Shell Thickness Variability

Absence of variability in shell thickness prevents evolutionary changes; all snails maintain the same shell thickness.
Non-heritable shell thickness means offspring do not inherit shell characteristics from parents.

Heritability and Population Dynamics

If shell thickness lacks heritability, the distribution of shell thickness among snails will be random over generations.
Predators’ selective pressure is crucial; if shell thickness does not influence survival, any snail, regardless of shell thickness, could be predated equally.

Mutations and Offspring

Majority of offspring from snail populations appear identical to their parents, but some may exhibit differences due to mutations.
Mutations affecting shell thickness occur with equal likelihood in both thin-shelled and thick-shelled snails.

Evolutionary Effects of Predation

Individual snails do not alter their shell thickness or color; rather, the population evolves as thinner-shelled snails are more likely to be predated.
Predators play a key role in evolution by selectively determining which snails survive to reproduce, influencing the gene pool of the next generation.

Description

Explore the concepts of shell thickness variability in snails and its impact on evolutionary processes. This quiz examines the heritability of shell traits, the influence of predation, and mutations within snail populations. Test your understanding of how these factors contribute to population dynamics and evolutionary changes.