It's worth noting that Aristotle's view of happiness was broader than the word means now. "Happiness" is not a perfect translation of what he meant.
Aristotle's goal, like many of his contemporaries, was about eudaimonia.
Rather than simply talking about the subjective feeling of happiness, he meant a sense of happiness worth having- happiness that is based on truth and virtue. His view of a "happy" or "eudaimon" person was someone who was virtuous in the sense that they are courageous, wise, skilled, and disciplined, and that they felt great achievement from who they are and what they've done. Someone can even be somewhat eudaimon even if they are fairly subjectively unhappy- like if they suffer great misfortune but they dealt with it in an honorable or fitting way.
I agree with Aristotle, and I agree with him more than with his contemporaries on this matter. I wouldn't particularly use the words "meaning and purpose", especially in a biological sense, but they are applicable in a philosophical sense.
