Phylogenetic tree branching

The scientific background:

A phylogenetic tree is a branching diagram showing the inferred evolutionary relationships among various biological species or other entities, based upon similarities and differences in their physical or genetic characteristics.
The taxa joined together in the tree are implied to have descended from a common ancestor.
Each node with descendants represents the inferred most recent common ancestor of the descendants. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed and they are the points in time when one species diverged in to two.

Link to Blossoms original video.

What does the branching out in a phylogenetic tree represent?

3 People tried to answer this question

Two new species that evolved from their common ancestor, like the Human and the Chimpanzee for example.

The geographical differences between members of the same species, like northern Europeans and southern Europeans.

The same species evolved new traits, like different fur color for example.

The features that are predicted to evolve in the future to a specific species.

You are Correct !

New traits, spicily different fur color does not mean that the spices have diverged into to two new species. 

Geographical differences don’t necessary mean different species.

The tree and it's branching only represent the inferred current or past relationships, it has no use for future evolutionary predictions.

1.  jabareen balsam (25.06.2017 pm 07.11.35)
  Hi vlad,

Polygonal tree branching is an interesting subject, which refers to evolution.

The scientific background enables understanding of the subject and also helps to answer the question. After reading the scientific background that explain the polygonal trees, I could understand this material easily. Also helps the student to answer the question.

The video is beautifully designed, we can see that you worked very hard on it, and the diagram with the writing below helps you understand the material without even reading the paragraph above. But it's hard to follow the writing and the chart at the same time. The writing is too small to read, and the words written inside the stars can not be read. The video was a little fast, it was better to slow it down.

The question is phrased clearly, but we need to prepare a question at a high level of thinking, and in my opinion the question is at a low level of thinking.

For the distractors, it is great that you post feedback after every distractor, that helps to understand why this is not the right answer, and gives the student the opportunity to think twice and get the right answer. but, the length of the distractors is uneven in size.

The overall question is good and concerning evolution issues.  that is relatively new and fun for the students.

Balsam Jabareen.



2.  harush naim mor (30.06.2017 pm 03.49.33)
הערכת עמיתים

Hi Majdi / vlad,

Nice question!

The background explains the subject in a superior and simple way,  gives the reader a good understanding required to answer the question. 

If I may suggest some ideas for improvement,

some changes in the animation, they would be:

  1. The script/letters in the animation were too small and I had I difficulty to read it.
  2. The display rate was too fast.
  3. There's currently no connection between examples of animals and the subject. It would be nice if you added (to the animation) pictures of animals which represent new species that evolved from their common ancestor.
  4.  It would be nice if you added music.

The distractors are good, in term of length and content,

And the overall question is very good!

Good luck,



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