Scientists believe this because they have a similar body model.
Scientists know that the supergroups do not share a single common ancestor but do not know where in time they branch off from each other:)
Scientists have identified Luca as the Last Universal Common Ancestor, or the common ancestor of all living organisms. Evidence for Luca comes from the study of genetic material and the similarities found in the genetic code of different species.
The branch point in a cladogram represents a specific ancestor that is separated into two or more species. For example a leopard and a house cat share a common ancestor. A similar example is that a wolf shares a common ancestor with the leopard's and house cat's ancestor but the wolf's ancestor lived longer than the leopard's and house cat's ancestor. Scientists use something called cladistics to determine the one common ancestor that multiple species have in common.
something to do with embryology
They look similar at birth
Back down the line, the species came from a common ancestor.
Scientists can determine if organisms share a common ancestor by analyzing their genetic and morphological similarities. The more similarities that exist, the more likely it is that they share a common ancestor. Additionally, the study of evolutionary relationships through techniques like phylogenetic analysis helps to trace back common ancestry among organisms.
A grasshopper.
The common ancestor is the Hyracotherium
Scientists found that both segmented worms and arthropods have a hollow space in their bodies to hold their organs. They both also have larvae stages early on in their life cycle.
Scientists believe that the common ancestor for several types of early humans, such as Homo neanderthalensis and Homo sapiens, was a hominid known as Homo heidelbergensis. This species is thought to have lived in Africa around 700,000 years ago and eventually migrated to Europe and Asia.
evolved from a common ancestor that also had the structure bg