Screen Brightness? , Del Key?

Hi:
I am new to Macs and I got this MacBook Pro (OS ver, 10,7,5),a few months ago, but I have a couple of questions:

1- Lately my screen keeps lighting up and then in a little while gets dim again?
I do not touch anything,(like the F1 & F2 keys which control brightness) it is like a very slow breathing, heh...

the Brightness gets intense then dims maybe 4 or 5 times per minute (sometimes it speeds up like when I stop typing, and it gets dimmer when I am typing) ?!
Is this a sign that a process or something is going on in the background? or is there a problem with this laptop?
(It is plugged into the wall and the green light on the plug is on))

2- I cannot find a regular Delete Key on this Mac? There is a (rather) large "delete" key on the top right of this keyboard but that is a BackSpace key and does not work like the Del key. I have to use the cursor keys then use del. to correct errors.

In fact I have the same problem using my iPhone (having no cursor keys there really gets on my nerves texting, lol)
Is there a delete key on this laptop?
Thanks a lot in advance and sorry for a long post...

Macs have an auto-adjust feature that adjusts the brightness on the display based off of the ambient light in the room. In your case though, it might be gone awry lol

Turn off auto brightness and see if that fixes it. Auto brightness is found in -SystemPreferences-Displays.

If you hold the fn key while hitting delete on Macs, it will function the same as the Windows delete key.

Also, try resetting the System Management Controller (SMC). See the following Apple KB article to learn how: LINK

The ambient light sensor is next to the iSight camera (to the left of it). If you have for some reason covered the camera or otherwise obscured the area around the camera, the sensor will try to adjust thinking it's in a dark room.

Thanks Adric, (chscag and S.SubZero) for quick n good reply(ies).
I did not know about the sensor and other things. It makes sense now cuz the light is behind me and I guess it was my own big head casting shadows on this sensor heh
Thanks a lot again cuz I am new to Mac (tho I have been doing PCs for many years) heh but this is sweet. I love to learn new things!
I appreciate your attitudes too.

Sometimes the worst problems seem to have the simplest solutions!
Regards;