To: Punctum Books
From: Anne Dalke  and Jody Cohen
Re: A Proposal for a New Project Exploring "Classroom Ecologies"
Date: October 4, 2013

This analysis and discussion activity focuses on two questions. How could something as complex as the human eye or the octopus eye have evolved by natural selection? How can scientists learn about the evolution of eyes, given that there is very little fossil evidence?

To answer these questions, students analyze evidence from comparative anatomy, mathematical modeling, and molecular biology. Students interpret this evidence to develop a likely sequence of intermediate steps in the evolution of complex eyes and to understand how each intermediate step contributed to increased survival and reproduction.

The Teacher Notes suggest additions to the Student Handout that can be used to introduce concepts such as the role of gene duplication in evolution and/or homology and analogy. 

In common experience, the term "adapting" usually refers to changes during an organism's lifetime.

In contrast, evolutionary biologists use the term "adaptation" to refer to a heritable trait that increases fitness.

To help students reconcile these different concepts, this activity introduces the concept of phenotypic plasticity (the ability of an organism to adapt to different environments within its lifetime).

Questions guide students in analyzing how the balance between the advantages and disadvantages of a characteristic (e.g. an animal’s color) can vary in different circumstances, how phenotypic plasticity can be a heritable trait that can optimize fitness in a variable environment, and how natural selection can influence the amount of phenotypic plasticity in a population.