What is the difference between Aleph-1 and aleph-2?

Could you please elaborate on the fundamental distinctions between Aleph-1 and Aleph-2? Are they different versions of the same technology, or do they serve distinct purposes within the cryptocurrency ecosystem? What are the key features that set them apart, and how do they compare in terms of performance, scalability, and security? Understanding these nuances is crucial for investors and developers alike.