Do fruit flies and humans have the same evolutionary relationship to wheat?

Expert Answers

An illustration of the letter 'A' in a speech bubbles

A good way to address your question is to look at a cladogram, which is a branching diagram showing the evolutionary relationships between organisms. Cladograms always begin with a single stem, which is divided again and again, representing separations into different related groups. A cladogram of the animal kingdom, for...

See
This Answer Now

Start your 48-hour free trial to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.

Get 48 Hours Free Access

A good way to address your question is to look at a cladogram, which is a branching diagram showing the evolutionary relationships between organisms. Cladograms always begin with a single stem, which is divided again and again, representing separations into different related groups. A cladogram of the animal kingdom, for instance, could illustrate the relationship between the group that includes humans, Chordata (animals having a spinal cord) and the group that includes fruit flies, Arthropoda (animals having jointed legs).

In a cladogram, branch points represent the most recent common ancestor of the organisms in the two branches. Ever since that ancestor, the two branches have developed separately. Thus we can describe the evolutionary relationship between two organisms by finding their most recent common ancestor, that is, the point where their portions of the diagram branched apart.

Wheat would not be featured on a diagram of the animal kingdom, because it is not an animal. It is a plant. To find an evolutionary relationship to wheat, we must go back farther. At the link below, there is a cladogram showing the most fundamental division of life into six kingdoms. You will have to scroll down past the chart and the first graphic until you see two images next to each other. The one on the left, that looks like a candelabra, is a cladogram of the kingdoms of life.

On this diagram, plants are indicated by a tree and the label Plantae, the biologists' name for the plant kingdom. Animals have a giraffe and the label Animalia. Looking below those labels, you can find the branch point, the most recent common ancestor between animals and plants. It is the second branch point down from the top; the left-hand branch becomes the Plantae, and the right-hand branch then divides into the Fungi and Animalia. All plants, including wheat, are in kingdom Plantae, so they are all in that left-hand branch. All animals, including fruit flies and humans, are in the kingdom Animalia, so they are all in the right-hand branch. That branch point represents the single common ancestor of wheat, humans, and fruit flies. The evolutionary relationship of humans to wheat is that our lineage separated at that point. The evolutionary relationship between fruit flies and wheat is also that their lineage separated at that same point.

Note that there are some differences between cladograms, and some of the relationships are different. This has to do with exciting new information scientists are learning from DNA regarding relationships and time since most recent common ancestor. It does not affect the answer to your question, however.

Approved by eNotes Editorial Team