That post could be improved with carriage-returns and better punctuation. I'm not trying to be a jerk, but I have read that three times and am not certain I understand what you are asking (or, indeed, if you are asking anything at all).
I think this is your question: "i dont understand realy is why large sensor pro cameras have huge zooms as can be seen by watching wildlife programns on tv."
I'm still not sure how to read that, but hopefully one of the following helps.
- Long focal-length lenses are used on wildlife programs to get good pictures of far away objects.
- Large sensors are used because
1) they receive more light per pixel, which allows lower ISO, faster shutter, and better focus,
2) you can get more pixels on them without problem, and
3) It's easier to get wider shots which, while not needed in the wildlife programs, are needed elsewhere in the industry.
- How much total light you can get to a sensor is a function of (in addition to ambient light levels and such)
1) How much light is in the degrees of vision being sampled (focal length)
2) How big a space you must project that onto (sensor size)
3) How much light you can take in per degree.
As your area of vision goes down (rise in focal length (expressed in "mm")), you get less light. To make up for this, you need a larger lens to bring more light in, or a smaller area to concentrate the light in (smaller sensor).
It is, therefore, easier and cheaper to build a zoom for a smaller sensor than a larger one. Those big lenses you see on professional wildlife shows cost many thousands of dollars each.