Cambrian Explosion

   Hello everyone! In this new blog post I will tell you about a life-changing event that happened a long time ago. Scientists thought this is like the 'big bang of biological explosion'. Yes, I am indeed talking about Cambrian Explosion (if you couldn't tell already by the title lol).

   First of all, what is Cambrian Explosion? To put it simply, it’s an event where major animals phyla started to appear. Here are some comparison. These are the organisms from Precambrian era, which were mostly consists of bacteria, protozoa, and the most complex one being Cnidaria or jellyfish.

Ocean life before Cambrian explosion

   However, after Cambrian explosion somehow these organisms had evolved to a much more complex one.

A diverse ocean life after Cambrian explosion

   The ocean life had changed, from simple, abstract, multi-cellular organisms to something that resembles the current phylum in the animal kingdom, mainly arthopodes and molluscs. The animals weren’t the best depiction of the current living species of animals, of course, most of these looked very bizarre. However, there is no doubt that Cambrian explosion was the foundation of modern animal kingdom.

You will not found most of these species in the ocean, but they're still similar tho!

   Cambrian period itself, which started after Cambrian explosion, obviously, happened back in 541 MYA-485.4 MYA. It was the first period of Paleozoic era, which means “ancient life”. It also started the Phanerozoic eon, which is the eon for the first phase of animal and plant life.

Timeline of Earth

   Here we have some examples of the animals living in this period. First and the most famous example is Trilobite. This fossil is a Walliseropstrifurcatus. This creature is considered to be the earliest known Arthopods because it matches the general description of that phylum. Physically, you can clearly see that this creature has segmented body and exoskeleton or hard shell that protect its body.

Walliserops trifurcatus' fossil

   We also have Anomalocaris. This is a part of Arthopod due to the segmented body and exoskeleton as well. However, what makes this and Trilobite different is that this thing is massive. Here’s a scale of Anomalocaris to a 1.8 m human. It’s about 1 metre long, have 32 overlapping plates, and also have mouth that could crush prey. It’s no wonder that this creature is the one of the biggest predator of Cambrian period.

Illustration of Anomalocaris 

   Last but not least, we have Conodonts. This organism is one of the first vertebrate that ever existed. This belongs to Pisces phyla, also known as fish. It’s a part of Agnatha superclass. An example of Agnatha that still lives to this day is Lamprey fish. 

   

Left is Conodonts, right is Lamprey fish. Very similar

   Now you might wonder how Cambrian explosion happened. There is still no conclusive conclusion to this, however there are several theories about it. The most popular one is the rise of oxygen in the sea due to phytoplankton booming in the ocean. Changes in the chemistry in the ocean caused by erosion allowed animals to develop things like shells and exoskeletons. However, some studies found that the oxygen rise has no significance at all. Some scientists even argued that Cambrian explosions happened because of the lack of oxygen.

   Regardless of the cause, there’s no doubt that this event changed life on Earth. It’s still the biggest “biological explosion” event that happened in the history, comparable to Big Bang. It’s even more revolutionary than dinosaur era despite that it’s relatively unknown to the masses. Without Cambrian explosion, who knows how life would look like? Would humans event exist without it?

   Thank you so much guys for reading this post, I know it's very rushed but I hope that you will gain some knowledge from this! See you next time!