Search results
Results from the WOW.Com Content Network
The organs of vision in mammals are, as a rule, well developed, although in their life they are of less importance than for birds: usually mammals pay little attention to immovable objects, so even cautious animals such as a fox or a hare may come close to a human who stands still without movement.
The visual system is the physiological basis of visual perception (the ability to detect and process light).The system detects, transduces and interprets information concerning light within the visible range to construct an image and build a mental model of the surrounding environment.
Visual acuity, or resolving power, is "the ability to distinguish fine detail" and is the property of cone cells. [42] It is often measured in cycles per degree (CPD), which measures an angular resolution, or how much an eye can differentiate one object from another in terms of visual angles. Resolution in CPD can be measured by bar charts of ...
The structure of an animal's eye is determined by the environment in which it lives, and the behavioural tasks it must fulfill to survive. Arthropods differ widely in the habitats in which they live, as well as their visual requirements for finding food or conspecifics , and avoiding predators.
The structure of the mammalian eye owes itself completely to the task of focusing light onto the retina. This light causes chemical changes in the photosensitive cells of the retina, the products of which trigger nerve impulses which travel to the brain. [18] In the mammalian eye, light enters the pupil and is focused on the retina by the lens.
There is a chordotonal organ located at the base of the wings in many insect orders, and, in Dipterans, there are also two chordotonal organs found at the base of the haltere. Their function is currently not well understood. In lacewings, a tympanal organ is located in the radius vein of the forewing and is thought to monitor ultrasound. [2]
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Nymphalid butterflies have the simplest eye ommatidium structure, consisting of eight photoreceptor cells (R1–R8) and a tiny R9 cell organized into a different tier. [5] These "R cells" tightly pack the ommatidium. The portion of the R cells at the central axis of the ommatidium collectively form a light guide, a transparent tube, called the ...