1/31/2010

Versatile Eyes of the Animals

From the one-celled amoeba to the great bald eagle, virtually every form of animal life responds in some way to light. The simplest animals–such as the amoeba–react only to changes in light and dark. The night-crawling earthworm is eyeless but its entire skin is covered with light-sensitive cells; sunshine–or even the beam from a powerful flashlight–sends it burrowing into the ground.

More highly developed animals, such as birds and mammals, have evolved complex eye structures which register detailed pictures of the world about them. Hawks and eagles, which have the keenest sight of all, can spot a rabbit hopping through underbrush a thousand feet below them. The giant eyes of these birds of prey actually outweigh their brains. The harassed rabbit has eyes placed on either side of its head in such a way that it can see a hawk swooping down from behind. An owl has huge saucerlike eyes to help it see at night, and the eye structure of the dragonfly gives it a keen ability to judge motion. In every case, the way an animal perceives light is dictated by its particular needs–the way it catches food, and whether its day begins at dawn or dusk.

Life Science Library - Light and Vision

1/28/2010

Light and Vision

Light and vision are always been such an interesting studies. Scientists and even ordinary man interested to explore this field. Because of this, I would rewrite some interesting study about light and vision that I’ve got from the book. I choose Life Time Library as my source because it have a complete series and all of the book is written in detail.

1/26/2010

Welcome Notes

Welcome to my blog. I hope you enjoy reading all my posts. Thank you.