1. Machine erodes
The human is a biological machine.
Everything except emotions and self consciousness can be applied to a machine. (Stand of today)
A machine is a robot made by human beings. This machine cannot survive by itself. It has no true emotions. It is missing curiosity and doubt, and is build only for a mission. If this mission is completed, it erodes.
2. Emotions & self consciousness
Again, the human is just an very advanced biological machine (depending on scientists in development for 10 millions of years).
If we are advanced enough we will be able to create sentient machines.
It's a matter how we define words. Human mankinds are NOT machines. Are you a machine? If yes, are you an advanced one? What is your advantage?
You want to make love with a sentient machine? What company should I invest into to offer this service to you?
3. Nature is in perfect sustainability
What about global killers?
Nature has a lot of random noises which is very logical if you believe in evolution.
You should read up more kneim to get up to date about science and philosophy.
Albert Einstein told us, "all is relative", and he is absolutely true. At this time the only global killer is human mankind. It will be stopped by natural rules.