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Eyes are something of an icon of evolution. How did such an integrated, multi-part adaptation evolve? While many different animals have complex eyes, untangling their evolutionary history reveals both remarkable diversity and surprising similarity.
UC Museum of Paleontology
Use this resource to relate evolutionary concepts to the topic of animal sensory and motor mechanisms (or get more suggestions for incorporating evolution throughout your biology syllabus). This online article includes animations and interactive portions. A worksheet that guides students through the article by asking them to answer questions is also available.
Correspondence to the Next Generation Science Standards is indicated in parentheses after each relevant concept. See our conceptual framework for details.
- There is a fit between organisms and their environments, though not always a perfect fit.
- An organism’s features reflect its evolutionary history.
- Some traits of organisms are not adaptive.
- There is a fit between the form of a trait and its function, though not always a perfect fit.
- Similarities among existing organisms (including morphological, developmental, and molecular similarities) reflect common ancestry and provide evidence for evolution.
- Features sometimes acquire new functions through natural selection.
- Not all similar traits are homologous; some are the result of convergent evolution.
- Inherited characteristics affect the likelihood of an organism’s survival and reproduction.
- Over time, the proportion of individuals with advantageous characteristics may increase (and the proportion with disadvantageous characteristics may decrease) due to their likelihood of surviving and reproducing.
- Traits that confer an advantage may persist in the population and are called adaptations.
- Complex traits can arise through the cooption of another trait.
- Evolutionary trees (i.e., phylogenies or cladograms) portray hypotheses about evolutionary relationships.
- Evolutionary trees (i.e., phylogenies or cladograms) are built from multiple lines of evidence.
- Evolutionary trees can be used to make inferences and predictions.