Busting a meme: Zakir Naik's statement that "A human eye is perfectly designed therefore cannot come through evolution."
Human eye with all its finesse is not a perfect design, neither is a human being. Through natural selection, different types of eyes have emerged in evolutionary history -- and the human eye isn't even the best one, from some standpoints. Because blood vessels run across the surface of the retina instead of beneath it, it's easy for the vessels to proliferate or leak and impair vision. So, the evolution theorists say, the anti-evolution argument that life was created by an "intelligent designer" doesn't hold water: If God or some other omnipotent force was responsible for the human eye, it was something of a botched design.
This meme is complete nonsense; Dr Naik's understanding of science is such a selective load of nonsense, he should not dabble in science.
Researchers at Lund University wanted to find out how long it might take for a complex eye to evolve: Starting with a flat, light-sensitive patch, they gradually made over 1,800 tiny improvements—forming a cup, constricting the opening, adding a lens—until they had a complex, image-forming eye. It is important to note that every tiny change these researchers made measurably improved image quality. The researchers concluded that these steps could have taken place in about 360,000 generations or just a few hundred thousand years. 550 million years have passed since the formation of the oldest fossil eyes, enough time for complex eyes to have evolved more than 1,500 times. Here’s how some scientists think some eyes may have evolved: The simple light-sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator. Random changes then created a depression in the light-sensitive patch, a deepening pit that made "vision" a little sharper. At the same time, the pit's opening gradually narrowed, so light entered through a small aperture, like a pinhole camera.
Every change had to confer a survival advantage, no matter how slight. Eventually, the light-sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens formed at the front of the eye. It could have arisen as a double-layered transparent tissue containing increasing amounts of liquid that gave it the convex curvature of the human eye.
In fact, eyes corresponding to every stage in this sequence have been found in existing living species. The existence of this range of less complex light-sensitive structures supports scientists' hypotheses about how complex eyes like ours could evolve. The first animals with anything resembling an eye lived about 550 million years ago. And, according to one scientist's calculations, only 364,000 years would have been needed for a camera-like eye to evolve from a light-sensitive patch.
Zoologist Dan-Erik Nilsson demonstrates how the complex human eye could have evolved through natural selection acting on small variations. Starting with a simple patch of light-sensitive cells, Nilsson's model "evolves" until a clear image is produced. Examples of organisms that still use the intermediary forms of vision are also shown.
For extensive reading please refer here: