Why Didn't the Ediacaran Biota Fill More Niches?

 The Ediacaran Biota seems to have been the first multi-cellular organisms on earth, living during the Vendian Period. No one is sure what they were. They died out once the Cambrian Explosion resulted in a large number of new forms of animal life appearing in the ancient seas. 

Most scientists acknowledge that the Ediacaran biota were not related to the later Cambrian forms. One role they play in the debate on creation is to show that hard shells are not required for fossilization- undermining the excuse that a lack of hard shells prior to the Cambrian explains the absence of reasonable evolutionary precursors to the explosion of forms in the Cambrian. Even without shells, if conditions are right, fossilization occurs. This makes it more likely that the reason that fossils of evolutionary precursors to the Cambrian forms are missing is that they did not exist. 

Of the many things that I find amazing about the Ediacaran forms is their lack of evolution. They expanded into a world where every macro niche was unfilled, yet over the course of 80-100 million years they apparently filled very few of them. This paper analyzed Vendian life-forms for where they lived in the ocean, their level of motility, and feeding strategy. This resulted in a matrix of 216 potential niches. As the paper notes:

The Ediacaran fauna utilized at most 12 modes of life, with just two practised by skeletal organisms.

They didn't evolve much. The Goldblum character from Jurassic Park's classic statement "life finds a way" wasn't true of Vendian Period forms. They didn't find a way. They left most niches wide-open for 80 to 100 million years. In contrast, the explosion of forms in the Cambrian quickly diversified as shown by their statement:

A total of 30 modes of life are recorded in the Early and Middle Cambrian, 19 of which were utilized by skeletal organisms. The other 11 are documented from soft-bodied animals preserved in the Chengjiang and Burgess Shale Konservat-Lagerstätten. The number of modes of life utilized by skeletal organisms increased by more than 50 per cent during the Ordovician radiation to a Late Ordovician total of 30....

The Ordovician radiation is another problem for naturalists. Life did not unfold they way their theories would have it. It isn't that species diversified into closely related ones, which over time became a new genus, then some from that became a new family, and then eventually some of that became a new order and so forth. Instead, the new phyla came first, then the new classes, and then the new orders. Only after an extended period of time did the process they call evolution begin to happen- with new species splitting and eventually forming a new genus and so forth. 

The early and middle Cambrian together lasted only 20 million years. Forty million years or so later the Ordovician came along. All of that together is less time than the Ediacaran forms had in the Vendian. Those forms basically didn't evolve. There was one burst in the Avalon where new forms show up. But they don't do a lot of subsequent changing. If evolution is fundamental to life, why didn't these things do it?

I don't have any hard answers here, only speculations. In the Christ-centered model Creation participates in its being filled to varying degrees by the "day" and type of living thing. With plants, it looks most like theistic evolution, with God simply commanding the land to bring forth "vegetation" and the land doing so without further direct intervention from God. God is giving the commands as if creation itself has some creative power. Later, God commands the seas to bring forth living creatures, but subsequent to that He intervenes on the job. One of the biggest theology points of the model is that the universe was made to be fit for beings like us- it can't do God's will without God's help either. 

So if I am speculating, and that is all this is at this point, perhaps the Ediacaran forms were an attempt of the earth to fill the waters with living creatures on its own. The result was inadequate and unsuitable. This deficit was cured by God's participation. This mirrors how our attempts to do good on our own fall flat, and are made fruitful only by operating in what He has done - the Atonement being the central example. 

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My book about early Genesis is far more about Theology than science, and that's good. I've come to see we won't really get the science right, big picture anyway, without getting the theology right. If you have found anything I say about the evidence from science in the least remarkable, know that it is nothing at all compared to the profound truths shown about the work of Christ in early Genesis as described in this book.

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