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The evolution of spiders' eyes has received little attention, and as such not much is known on the subject. The principal and secondary eyes likely evolved separately, with the principal eyes being homologous to the ocelli of insects but the secondary eyes being derived from compound eyes.
A spider web preserved in amber, thought to be 110 million years old, shows evidence of a perfect "orb" web, the most famous, circular kind one thinks of when imagining spider webs. An examination of the drift of those genes thought to be used to produce the web-spinning behavior suggests that orb spinning was in an advanced state as many as ...
Spiders do not have compound eyes, but instead have several pairs of simple eyes with each pair adapted for a specific task or tasks. The principal and secondary eyes in spiders are arranged in four, or occasionally fewer, pairs. Only the principal eyes have moveable retinas. The secondary eyes have a reflector at the back of the eyes.
Jumping spiders have some of the best vision among arthropods — being capable of stereoptic color vision — and use sight in courtship, hunting, and navigation. Although they normally move unobtrusively and fairly slowly, most species are capable of very agile jumps, notably when hunting, but sometimes in response to sudden threats or ...
The snake detection theory (SDT), [1] [2] [3] also sometimes called the snake detection hypothesis, suggests that snakes contributed to the evolution of visual systems in primates. According to the theory, predatory pressure on early primate populations from snakes selected individuals who were best able to recognize them, improving their ...
"Evolution of the Eye". WGBH Educational Foundation and Clear Blue Sky Productions. PBS. 2001. Creationism Disproved? Video from the National Center for Science Education on the evolution of the eye; Evolution: Education and Outreach Special Issue: Evolution and Eyes volume 1, number 4, October 2008, pages 351–559. ISSN 1936-6426 (Print) 1936 ...
ZenaTech (Nasdaq: ZENA) is a technology company specializing in AI drone solutions and enterprise SaaS solutions for mission-critical business applications. Since 2017, the company has leveraged its software development expertise and grown its drone design and manufacturing capabilities through ZenaDrone, to innovate and improve customer ...
Sometimes the needs for visual acuity in different functions conflict, and different parts of the eyes may be adapted to separate functions; for example, the Gyrinidae spend most of their adult lives on the surface of water, and have their two compound eyes split into four halves, two for underwater vision and two for vision in air. Again ...