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Cake day: July 6th, 2023

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  • As others have stated, water in trees gets up thanks to two processes. The first is indeed capillary action. The tubes carrying the water are rather thin, and it clings to the sides of it. But this is a rather small part of the total energy carrying the water. The main mechanism is a negative pressure inside the vascular system of the tree. Basically, tree leaves sweat water all the time (more or less depending on temperature). The water leaving the tree kind of sucks up the water following inside the vessels (this is a simplification to not go into the physics behind). In some larger trees, the negative pressure inside the vascular system can be exceptionally strong, requiring exceptional strength of the tree’s components.




  • In phylogeny, genomic is just another tool. The point is that turtles are os course animals, but they do branch off of different reptile groups if you look at morphological evidence (which includes fossil data) or at molecular (genetic) evidence (which only includes extant species). This is not something frequent, as usually molecular evidence tends to strengthen previous morphologically established evolutionary relationships. And even though molecularists are more numerous today, their methods are neither better or worse than anatomy.

    Phylogeny is not as straightforward as some people make it seem, and especially molecular phylogeny tends to rely on abstract concepts that can’t always be backed up by biological evidence (I’m not saying it’s wrong, it’s very often very good, juste that a lot of people doing it do not understand the way it works, and thus can’t examine the process critically).

    And so turtles’ origin are still very much an active debate!