Perfection of appeal; mandatory, jurisdictional

It is settled that the perfection of an appeal in the manner and within the period set by law is not only mandatory, but jurisdictional as well, and that failure to perfect an appeal within the period fixed by law renders the judgment appealed from final and executory.[1] The Supreme Court’s pronouncement in Team Pacific Corporation v. Daza[2] is instructive on this matter, to wit:[3]
Although appeal is an essential part of our judicial process, it has been held, time and again, that the right thereto is not a natural right or a part of due process but is merely a statutory privilege. Thus, the perfection of an appeal in the manner and within the period prescribed by law is not only mandatory but also jurisdictional and failure of a party to conform to the rules regarding appeal will render the judgment final and executory. Once a decision attains finality, it becomes the law of the case irrespective of whether the decision is erroneous or not and no court — not even the Supreme Court — has the power to revise, review, change or alter the same. The basic rule of finality of judgment is grounded on the fundamental principle of public policy and sound practice that, at the risk of occasional error, the judgment of courts and the award of quasi-judicial agencies must become final at some definite date fixed by law.
[1] See Securities and Exchange Commission v. PICOP Resources, Inc., 588 Phil. 136, 154 (2008), citing Land Bank of the Philippines v. Ascot Holdings and Equities, Inc., 562 Phil. 974, 983-984 (2007).
[2] G.R. No. 167732, July 11, 2012. 
[3] Id. at 95, citing Zamboanga Forest Managers Corp. v. New Pacific Timber & Supply Co., 647 Phil. 403, 415 (2010).