Final answer:
The three major domains of life are Archaea, Bacteria, and Eukarya. Archaea and Eukarya share a common ancestry, while Bacteria are evolutionarily distinct. LUCA is the hypothetical common ancestor of all life on Earth.
Step-by-step explanation:
The three major domains of life are Archaea, Bacteria, and Eukarya. These domains represent the highest level of classification for living organisms. LUCA, which stands for Last Universal Common Ancestor, is the hypothetical common ancestor of all life on Earth.
Archaea and Bacteria are both prokaryotes, meaning they lack a nucleus and other membrane-bound organelles. Eukarya, on the other hand, includes organisms with a more complex cellular structure, such as plants, animals, fungi, and protists.
The relationship between the domains is that Archaea and Eukarya share a common ancestry, suggesting that Archaea gave rise to Eukarya. This is supported by genetic evidence showing similarities between archeabacterial genes and eukaryotic genes. Bacteria, while also prokaryotic, are evolutionarily distinct from Archaea and Eukarya.