A dead person is not alive. A fetus is. The fetus has metabolism and growth.
1. Let us examine your points. I will try to be as specific as possible.
1. Yes. I know a fetus is alive and a dead person isn't. That's a valid point, but that is not the point that was made earlier. The vast majority of anti-abortionists use the argument: "you cannot kill it, because it is alive. It is separate as an entity and has unique DNA." The first point is totally irrelevant, since the fact that something is alive does not mean you cannot kill it morally.
Let's examine the second point you bring up: the fetus metabolizes, grows. I do not belive this gives something, according to my philosophy, a right to life, nor do I think it gives something moral consideration because similarily, most every cell in your body metabolizes and grows and replicates. You as an entity are alive and grow and metabolize just as do your cells. So, if your argument is that since the fetus does all three, you cannot kill it, then you must accept that it is also wrong to draw blood or test on human tissue because you are killing living material that does all three of the things you mentioned. Now, if you want to go with something a bit more substantive, like sentience, then I will agree it is wrong to hurt or kill something if the good does not outweigh the negative.
The fetus is devoping the reproductive ability until it has entered puberty
I don't understand this point. Are you trying to say that a fetus enters puberty? A fetus is born and becomes a newborn well before it enters puberty in the pre-teen years. By then, the individual has more value because of its sentience.
and murdering a pre-pubesent child is illegal, and generally considered immoral (which calls the entire scientific definition of life into question in this matter).
It is only wrong to "murder" a pre-teen because it is a sentient being, not because of anything to do with its sexual maturity. You have to critically analyse why it is wrong to kill adults and children--they have rational attributes. A frog eventually reaches sexual maturity and puberty. That does not logically follow that the being has any moral consideration.
A fetus will likewise have response to stimuli and adaptation to the environment. The fetus has a heartbeat at 18 days after conception. The fetus has barin waves and independant movement at 6 weeks after conception. A baby is able to respond to sound or touch at 8-10 weeks. Most abortions are not carried out until 8 weeks after conception.
Yes. It can respond to stimulie with automatic reflexes. So? So what if it has a heart beat? So did Terry Schivo. She was worth little too. Obviously, heartbeat is not what gives something moral consideration and right to life.
However, I agree with you that brainwaves appear anywhere from around 6-8 weeks. However, even this is a problematic criterion.
A fetus can think, can act, and can sense by 8 weeks, which is again when most abortions are carried out. Because you are incorrect in this, you are incorrect about abortion. Is a fetus able to think as well as a human that has been born? No. Of course neither is a dog, but it's generally considered immoral to kill a dog. A dog isn't even human. Can a fetus sense as well as a human that has been born? No, but neither can a blind man. Can a fetus move like a human that has been born? No, but neither can someone who is crippled. A fetus is not aborted when it is a clump of cells as you would ahve everyone believe. The abortion happens upon the dawn of sentience.
No, a fetus cannot "think" and act. It can do litterally nothing. It's brain is in infancy. I am not incorrect on this, and I never said that brian waves don't appear at 7-8 weeks. Show me where I said that.
What makes you think I am for late term abortions? However, I would like some evidence that shows they can think at 8 weeks. The problem with sentience is that the fact that it is in someone else's body changes the equation. It
would be wrong to kill a sentient being if it were alone, but the same does not necessarily follow if it is inside of you. You have conflicting rights. Personhood beings with self awareness or some derrivation of it.
I can direct you to an excellent work of ethics on this topic:
1.
http://www.utilitarian.net/singer/by/200509--.htm
2.
http://www.utilitarian.net/singer/by/1993----.htm
They are both excellent treaties on utilitarian bioethics that generally categorize the majority of utilitarian argumentation for abortion.