Question: What is the significance of the freshwater fish groups represented by the individuals pictured below?
Believe it or not, the answer is as follows: The most recent evolutionary analysis says that nearly all saltwater fishes* evolved from fishes that were members of these freshwater groups!
Confused? You should be. Let me see if I can help clear things up for you. Greta Carrete Vega and John J. Wiens recently published a scientific paper entitled, “Why are there so few fish in the sea?”1 In it, they attempt to explain why there are so few fish species in the seas as compared to the number of fish species found in freshwater sources. After all, the seas cover about 70% of earth’s surface, while freshwater lakes, rivers, and streams cover only about 2%. Despite this huge difference in living space, there are significantly more freshwater fish species than there are saltwater fish species. With all the resources at their disposal, while haven’t saltwater fishes diversified into many more species?
To answer this question, they looked at DNA data as well as fossil data regarding the ray-finned fishes. This group contains about 96% of all fish species (from both freshwater and saltwater), and it is the most diverse group of fishes in the seas. When they compared all the fishes, they found that the freshwater fish groups represented by the individuals pictured above make up the basal groups for all the ray-finned fishes. In other words, according to their analysis, these three freshwater fish groups came first, and the currently-living saltwater ray-finned fish evolved from them! Indeed, their analysis indicates that the freshwater common ancestor of the Polypteriformes and the Acipenseriformes pictured above appeared about 300 million years ago (using scientifically-irresponsible dating techniques), and the first ancestor that led to the currently-known saltwater fishes evolved from these groups more than 100 million years later!
Now remember, not all saltwater fishes are ray-finned fishes. However, the vast majority of them are. So according to this analysis, the vast majority of fishes that are currently living in the ocean actually evolved from freshwater fishes! Now, of course, this appears to contradict what we see in the “geological column,” since the first fishes that appear there are supposedly marine fishes. Not to worry, of course. There is an explanation. According to the authors:2
Our results suggest that ancient extinctions in the marine environment may have wiped out the earliest ray-finned fishes living in the oceans, that the oceans were then recolonized from freshwater habitats, and that most marine fish species living today are descended from that recolonization (leaving less time for biodiversity to build up in the oceans)…This pattern of ancient extinction and more recent recolonization may help explain why the oceans are now so species-poor, even for fish.
So…in order to believe the supposed evolutionary history of most currently-living fishes as well as geological-column reasoning (which doesn’t work very well), here’s what you are forced to believe: Fish first evolved in the seas, and this eventually led (somehow) to freshwater fish. Then, mass extinctions in the oceans occurred, wiping out nearly all saltwater fish. Then, the freshwater fish were (somehow) able to recolonize the oceans, “rebooting” the evolution of saltwater fish.
I am glad that I’m not an evolutionist! I just don’t have enough faith to believe the wild scenarios that evolutionists must concoct in order to force the data into agreement with their cherished ideas.
* Note that “fish” is the proper plural when you are discussing multiple fish of the same species. On the other hand, “fishes” is the correct plural when you are discussing multiple fish of different species. An aquarium with 8 goldfish is full of fish. However, an aquarium with 7 goldfish and one angelfish is full of fishes.
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