Related Experiment Video
Updated: Aug 10, 2026
09:10
A Protocol for Bioinspired Design: A Ground Sampler Based on Sea Urchin Jaws
Published on: April 24, 2016
Dollo's law and the re-evolution of shell coiling
Rachel Collin1, Roberto Cipriani
1Smithsonian Tropical Research Institute, Unit 0948, APO AA 43002, USA. rcollin@naos.si.edu
Proceedings. Biological Sciences
|January 20, 2004
Summary
Gastropods can re-evolve coiled shells, challenging evolutionary assumptions. This study shows that the genetic basis for coiling persists even after millions of years of shell loss in limpets.
Area of Science:
- Evolutionary biology
- Developmental biology
- Gastropod research
Background:
- Gastropods frequently lose coiled shells, adopting limpet-like forms.
- Limpets are often considered evolutionary dead-ends, unable to regain complex traits like coiled shells.
- Dollo's law suggests re-evolution of lost complex characters is unlikely due to genetic degradation.
Purpose of the Study:
- To investigate the potential for re-evolution of coiled shells in gastropods.
- To examine the Calyptraeidae family for evidence of coiled shell re-evolution.
- To understand the developmental mechanisms underlying character re-evolution.
Main Methods:
- Quantifying shell coiling levels in Calyptraeidae limpets.
- Analyzing evolutionary history and genetic architecture of coiling.
- Comparing heterochrony and heterotopy in character re-evolution.
Main Results:
- Coiled shells have re-evolved at least once within the Calyptraeidae family.
- The genetic and developmental mechanisms for coiling were retained for 20-100 million years.
- Re-evolution occurred through changes in developmental timing (heterochrony).
Conclusions:
- The re-evolution of complex characters, like coiled shells in gastropods, is possible.
- Developmental plasticity allows for the re-emergence of lost traits.
- This challenges Dollo's law and expands our understanding of evolutionary potential.
Related Concept Videos
02:56The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
01:54Convergent Evolution
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.The structures that arise from convergent evolution are called analogous structures. They are similar in function even if they are dissimilar in structure. Further, structures can be analogous while also...
01:25Divergence and Curl of Electric Field
The divergence of a vector is a measure of how much the vector spreads out (diverges) from a point. For example, an electric field vector diverges from the positive charge and converges at the negative charge. The divergence of an electric field is derived using Gauss's law and is equal to the charge density divided by the permittivity of space. Mathematically, it is expressed as
01:15Divergence and Curl
The divergence of a vector field at a point is the net outward flow of the flux out of a small volume through a closed surface enclosing the volume, as the volume tends to zero. More practically, divergence measures how much a vector field spreads out or diverges from a given point. For an outgoing flux, conventionally, the divergence is positive. The diverging point is often called the "source" of the field. Meanwhile, the negative divergence of a vector field at a point means that the vector...
01:18Castigliano's Theorem
Castigliano's theorem analyzes displacements and rotations in elastic structures. It relates the derivative of elastic strain energy to the applied forces or moments, allowing for the calculation of deformations. The theorem states that the partial derivative of the total strain energy of a system with respect to a specific load results in the displacement at the point where the load is applied. This principle applies to both forces and moments.
01:23The Chain Rule: Problem Solving
The thermal expansion of a metal rod shows the application of the Chain Rule when one physical quantity depends on another that varies with time. As the rod is heated, its length changes according to linear thermal expansion, while the temperature of the system varies quadratically with time.For linear thermal expansion, the length L of the rod depends on temperature T such that the rate of change of length with respect to temperature is constant:where L0 = 2 m is the initial length of the rod,...