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.
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]
The structure of the brain region (barrel cortex) which receives information from the vibrissae is similar to that found in the visual cortex which permits the cat to create a three-dimensional map of its surroundings. This does not mean that sensing with vibrissae is a type of vision.
Compound eye of a house centipede Compound eye of a dragonfly. A compound eye is a visual organ found in arthropods such as insects and crustaceans.It may consist of thousands of ommatidia, [1] which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distinguish brightness and color.
The visual systems of Chelicerata (the sister group to the remaining Arthropoda) are less well understood. It has been shown that homologs of many eye patterning genes are variably expressed in the eyes of different spider species, but the functional significance of these changes in expression is not well understood, due to lack of functional data.
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 ...
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!
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.