Is using ubuntu amnesic as Tails and therefore prevent fingerprinting? Can I use ubuntu as an alternative to Tails? I think ubuntu too only use the RAM and destroy all memory after shutting down, and hence fulfill the purpose of Tails.
Ubuntu is not a privacy-focused distro, quite the opposite. Ubuntu does not wipe the memory. Ubuntu does not prevent fingerprinting.
Tails has many great security optimisations, including firewalling, pre-configured stream isolation, and so on.
You can do all this on Ubuntu, too, but Tails is pre-configured and "just works."
Just go with Tails.
If you are an expert at internet security and anonymity, you may configure Ubuntu to work for you. But if you are not a security and anonymity expert, use Tails until you get enough expertise and experience in these fields. Tails is the result of many security and anonymity experts putting their heads together for many years, and result of many revisions and enhancements over the years. It is highly unlikely that any individual be able to much that level of sophistication in any reasonable amount of time. Also, remember that both Tails and Tor are work in progress for a foreseeable future. By the way Dave's characterization of Ubuntu is on the mark. Finally having said all of the above, keep in mind that nothing is perfect and if one poke enough at anything, one will finally find a counter measure to neutralize it.