Final answer:
Biologists observe various stages of eye development across species, implying that eyes evolved incrementally. Evolutionary evidence is supported by the presence of vestigial structures and similarities in embryonic development. The biology of vision encompasses light detection and processing, illustrating evolutionary adaptability.
Step-by-step explanation:
When considering the complexity of the eye and its evolution, biologists examine evidence across different species and developmental stages. The idea that 'any less complex structure would be nonfunctioning' is a misconception. In reality, we have observed various stages of eye development, from simple light-sensitive cells to complex structures featuring a cornea, lens, and retina. These various forms of eyes demonstrate how incremental changes can lead to fully functional and complex organs in a process known as evolution.
Furthermore, vestigial structures and embryological evidence support the evolutionary view. For example, moles have vestigial eyes, and embryos of different species show striking developmental similarities. This demonstrates the evolutionary modification and repurposing of existing structures rather than the creation of entirely new ones from scratch.
The biology of vision involves more than just the detection of light; it also encompasses the processing of signals and integration of sensory information in the brain. The variety in eye structures across the animal kingdom, such as the complex eyes of cubozoans and the variable light detection in human eyes, showcases the evolutionary adaptability and diversity of visual systems.