Explain the logic behind the claim that the nuclear envelope is a synapomorphy that defines eukaryotes as a monophyletic group.

Verified step by step guidance

1. Understand the definition of synapomorphy: A synapomorphy is a characteristic or feature that is shared by two or more taxa and is derived through evolution from a common ancestral form. In this context, it is a trait that is present in an ancestor and all its descendants, distinguishing them from other organisms.
2. Identify the structure in question: The nuclear envelope is a double membrane structure that encloses the nucleus in eukaryotic cells. It separates the genetic material from the cytoplasm and regulates the flow of molecules in and out of the nucleus.
3. Recognize the uniqueness of the nuclear envelope: The nuclear envelope is unique to eukaryotic cells and is not found in prokaryotic cells (bacteria and archaea), which have no nucleus and instead have their genetic material freely floating in the cytoplasm.
4. Connect the nuclear envelope to eukaryotic identity: Since all eukaryotic cells, from single-celled organisms to cells in multicellular organisms like plants and animals, possess a nuclear envelope, it serves as a distinguishing feature that sets them apart from prokaryotes.
5. Conclude its role as a synapomorphy: The presence of the nuclear envelope in all eukaryotic cells and its absence in prokaryotic cells supports the claim that the nuclear envelope is a synapomorphy. This feature supports the classification of eukaryotes as a monophyletic group, meaning all members of this group are descended from a common ancestor that originally evolved this trait.