The Sequence of Evolution

One of the basic assumptions of evolution, and not an unreasonable one, is that life developed from simple to complex. This is logical, because the simpler something is, the more likely it would come into existence by random events—the only possible source, if no intelligent intervention can be considered. From this comes a general principle that the simpler an organism is, the more likely that it is primitive, or even possibly the predecessor of more complex forms of life. Thus we see simpler animals being called “primitive,” and organisms lacking a membrane-bound nucleus being called prokaryotes (roughly, “first seed”). And the simplest prokaryotes are called archaebacteria (“ancient bacteria”).
There is another assumption of evolution that is related to the first: To keep the evolutionary process as simple (and design-free) as possible, there is no backtracking allowed. In other words, once a new life component comes into existence, it stays there or disappears permanently. In any given advancement stream there is not a coming into existence of complexity, a reversal, and a reintroduction of the same complexity again later. The probability of this is a geometric leap. The practical corollary of this requirement of process simplicity is that any organism that is missing some feature cannot be the intermediary between two other organisms that have that feature.
This is all well and good, until you actually try to sequence known organisms by complexity. For example, archaebacteria are considered to be simpler (more ancient) forms of prokaryotes, having similar simple structure; yet they have a higher DNA language identical with eukaryotes (a name which roughly means “better seeds”).
Let’s go up a notch and try again: The simplest know animal (multi-cellular organisms called metazoan) is the Trichoplax adhaerens (placozoan), the only known species in its entire phylum. This organism only has four types of cells in its body, placing it way behind sponges, which have around 50. The problem here is that it has extracellular proteins in common with all other animals except sponges—a problem if it’s supposed to be the poster child for oldest evolved animal.
Science textbooks never bring this up, but it is why they tend no to longer picture a tree of life, with organisms at the junctures; but instead show a binary branching geometric, with know animals always at the ends of branches. They know there is no evidence for sequencing.