It’s ironic how calling a person a “monkey” or “orangutan” is considered offensive when we all know that humans are descended from these apes. Well, sometimes it is hard to find logic in the customs and practices of our society, but if you are willing to find the path of evolution that turned monkeys into modern humans, you may find the details in the fossil records.

Fossils are basically the preserved remains traces or impressions of prehistoric living beings. Whether you realize this or not, the fuel (the non-renewable ones) used to power our vehicles and homes is also derived from fossils.

While fossil fuels may have a significant role in the recent progress of humankind, fossils have actually allowed us to understand the process of evolution that allowed single-cell organisms to evolve into complex living beings. Apparently, the fossils are our only actual glimpse into the past.

Stenopterygius fossil
Fossil of Stenopterygius, an extinct reptile- taken at Museo de la Naturaleza y el Hombre – Tenerife. Image: Wikipedia user Ghedoghedo Stenopterygius is an extinct genus of thunnosaur ichthyosaur known from Europe (England, France, Germany, Luxembourg, and Switzerland). The maximum length was 4 meters (13 feet). The habits of Stenopterygius were similar to those of present-day dolphins. It spent most of its life in the open sea, where it hunted fish, cephalopods, and other animals. The abdominal cavity of skeletons of this ichthyosaur often contains the remains of such food.

What is a fossil record?

The fossil record is a term commonly used by paleontologists to refer to the list of fossils that have been discovered and also applies to the information derived from the same. Since fossilization is a rare event, we cannot consider the fossil records to be complete, but there are actually some insightful data that helps us get a clear view of the evolution of life on earth.

If you study the fossil record, you may find that the development of organisms indicates a history of incremental succession from one species to another. It suggests that these were simple organisms at first, while the complex organisms start to appear over time. Furthermore, the characteristics of the newer organisms often appear to be similar to the characteristics of older organisms, but in modified forms.

The succession of life forms ranges from something simple to more complex and advanced, allowing us to understand the relationships between the new life forms and their predecessors. While it serves as strong inferential evidence of evolution, there are certain gaps in the fossil record that leave room for speculations, but there’s no denying the incremental development that is highlighted in the fossil record.

However, the fossil record does not make any suggestion to the idea of a sudden generation of life as it appears now, nor is it supportive of transformations. Even though there are several gaps in the fossil record, it only points towards evolution and common descent.

The only problem with inferential evidence like fossil records is that one can always, in theory, challenge such evidence on its interpretation, asking why they interpret the evidence as inferring one thing instead of the other. However, such a challenge is only valid when someone comes with a stronger alternative that not only offers a better explanation to the evidence but also explains the other evidence that the first explanation failed to address.

Interestingly, the people who contradict the idea of evolution do so because they regard to evidence to be “merely” inferential and also fail to present an alternative explanation that can describe the inferential evidence better than the evolution. As you may realize, inferential evidence may not be as strong as direct evidence, but it is treated as sufficient in most cases where enough evidence is present, with no other reasonable alternatives.

Fossils and converging evidence

There is no denying the fact that the fossil record is an important piece of evidence that suggests the existence of evolution. However, the claim can be much stronger if other pieces of evidence besides fossil records also support the concept of evolution.

It is proven that the fossil record remains consistent in terms of biogeography. So, if evolution is true, it would mean that the fossil record would also be in synchronization with things like current biogeography, the phylogenetic tree, and the knowledge of ancient geography supported by plate tectonics.

Some findings, such as the fossil remains of marsupials in Antarctica support the theory of evolution quite strongly. The theory focuses on the fact that South America, Australia, and Antarctica were once part of the same continent.

Also, if evolution is true, then the succession of organisms would also be seen in the living creatures at present, and not just in the fossil record. Surprisingly, the succession seen in the record is also quite compatible with what has been derived from the study of currently living creatures. Numerous studies suggest that the general order of development for the major types of the vertebrate animal was:

Fish > Amphibians > Reptiles > Mammals

Interestingly, the fossil record also shows the same order of succession. In fact, the fossil record is consistent with the developmental order that was derived from the study of currently living species.

Fossils and scientific predictions

If the common descent happened, then we should also be able to predict and even retrodict what we would see in the fossil record. Also, the organisms found in the fossil record should conform to the phylogenetic tree. The nodes on that tree, especially where the split occurs represent the common ancestors of the organisms on the newer branches of that tree.

The predictions may lead us to find the organisms in the fossil record showing characteristics that are intermediate in nature between various organisms that evolved from it and from the organisms from which it evolved. For instance, the standard phylogenetic tree suggests that birds are most closely related to reptiles. So it wouldn’t seem weird if we predict to find fossils that demonstrate a combination of the characteristics of a bird and a reptile.

Fossilized organisms that exhibit intermediate characteristics are known as transitional fossils. Interestingly, these kinds of fossils have already been found. Furthermore, we would also expect that we would not get to see any intermediated characteristics between organisms that are not closely related. For instance, we would not expect to see fossils of organisms that appear to be the intermediates between fish and mammals, or birds and mammals.

Some notable transitional fossils

Over the past couple of decades, a significant number of transitional fossils have been found that fill the gaps which were thought to be unbridgeable. Interestingly, the paleontological history of the earth is now much more well-understood than it was a few decades ago.

Notably, a team of researchers from the U.S., China, and Italy discovered an intermediate fossil that had large flippers which allowed them to walk on land like a seal. This 2014 discovery has challenged the creationists who believed in dolphin-like reptiles, popularly referred to as ichthyosaurs.

Some of the other recent discoveries include multicellular life well before the Cambrian explosion, 30 different intermediate fossil species that support the transition between land mammals and marine mammals, “Tiktaalik” – an intermediate of fish-tetrapod transition, 20 different prehuman species, and much more.

As mentioned earlier, the fossil record is not complete as fossilization is a rare process. But again, this is the best chance we have in understanding the evolution of life on Earth. So, unless there is a better alternative to the fossil record, there’s no reason to doubt the incremental development that is supported by the inferential evidence.

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