What is the legal test for second degree murder?

" 'On appeal we review the whole record in the light most favorable to the judgment to determine whether it discloses substantial evidencethat is, evidence that is reasonable, credible, and of solid valuefrom which a reasonable trier of fact could find the defendant guilty beyond a reasonable doubt. [Citations.] The standard of review is the same in cases in which the People rely mainly on circumstantial evidence. [Citation.] "Although it is the duty of the jury to acquit a defendant if it finds that circumstantial evidence is susceptible of two interpretations, one of which suggests guilt and the other innocence [citations], it is the jury, not the appellate court which must be convinced of the defendant's guilt beyond a reasonable doubt. ' "If the circumstances reasonably justify the trier of fact's findings, the opinion of the reviewing court that the circumstances might also reasonably be reconciled with a contrary finding does not warrant a reversal of the judgment." ' [Citations.]" [Citations.]' The conviction shall stand 'unless it appears "that upon no hypothesis whatever is there sufficient substantial evidence to support [the conviction]." ' " (People v. Cravens (2012) 53 Cal.4th 500, 507-508).

Second degree murder "is 'the unlawful killing of a human being with malice aforethought but without the additional elements, such as willfulness, premeditation, and deliberation, that would support a conviction of first degree murder.' [Citation.] Malice may be either express (as when a defendant manifests a deliberate intention to take away the life of a fellow creature) or implied. [Citation.] 'Malice is implied when the killing is proximately caused by " 'an act, the natural consequences of which are dangerous to life, which act was deliberately performed by a person who knows that his conduct endangers the life of another and who acts with conscious disregard for life.' " [Citation.] In short, implied malice requires a defendant's awareness of engaging in conduct that endangers the life of another.' " (People v. Cravens, supra, 53 Cal.4th at p. 507.)