What is the difference between paralogous and orthologous genes in terms of their evolutionary relationships and functions?

Paralogous genes are genes that arise from a gene duplication event within the same species, leading to multiple copies of a gene with similar functions. They can evolve new functions over time. Orthologous genes, on the other hand, are genes that are derived from a common ancestor through speciation, leading to genes with similar functions in different species. They typically retain the same function across different species.