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p. 11. The first eyeslocked

  • Michael Land

Abstract

The evolution of eyes started slowly in the Precambrian and then took off during the Cambrian period, between 541 and 485 million years ago. ‘The first eyes’ describes the first step in vision as the process of converting light into electrical signals, which is triggered by the rhodopsin molecule shared by all animals. It states that an eye must contain at least two photoreceptors with different fields of view, so that comparisons can be made simultaneously between light from different parts of the environment. The different types of single-chambered eyes (pigment cup, lens, cornea, and concave mirror) and compound eyes (basic compound, apposition, refracting superposition, and reflecting superposition) are described.

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