Protein families are groups of proteins that share a common evolutionary origin, structure, or function. These proteins often have similar amino acid sequences and perform related biological roles in organisms. For example, the globin family includes proteins like hemoglobin and myoglobin, which are involved in oxygen transport and storage. The classification of proteins into families helps scientists understand their functions and relationships. By studying protein families, researchers can identify conserved features that are crucial for their activity. This knowledge is essential for fields like biochemistry and molecular biology, where understanding protein interactions and functions is key to advancing medical and scientific research.