What is the difference between a murder premised on a general intent and a specific intent crime?

"A general intent crime is one that only requires the actor intend the act which constitutes the crime. [Citation.] A specific intent crime is one that requires the actor intend not only the proscribed act, but also that he intend some further act or additional consequence. [Citation.] A general intent crime may also involve a specific mental state, such as knowledge. [Citations.] [p] First degree murder and second degree murder premised on express malice involve the specific intent to kill, whereas second degree murder premised on implied malice involves a general intent to do the act and the mental state of knowledge and conscious disregard for the risk to human life. (See People v. Murtishaw (1981) 29 Cal.3d 733, 764-765 [175 Cal.Rptr. 738, 631 P.2d 446].)" (Cleaves, supra, 229 Cal.App.3d at p. 380, 280 Cal.Rptr. 146.)