Cambrian Explosion

How Earth's greatest evolutionary leap changed everything.

INTRODUCTION: The explosion which changes the whole earth from lifeless to full of life.

Cambrian Explosion was the rapid evolution diversification between about 541 and 530 million years ago in the early Paleozoic, during which mostly animal phyla first appeared, including early Chordata and Arthropoda. Before Cambrian explosion the life was very simple with no complexity, unicellular organisms were found or small multicellular organisms they live in colonies. But after the acceleration in the rate of diversification, they start appearing complex gradually.

what was before the Cambrian?

Before Cambrian mean before the Paleozoic era there was the existence of three periods named as Hadean, Archean, Proterozoic collectively called as Precambrian Supereon. In Precambrian photosynthesis start taking place by cyanobacteria, stabilization of Earth’s crust, ocean formed and atmosphere gradually accumulate oxygen and this oxygenation event known as Great Oxidation Event. After this event evolution start taking place slowly and gradually. Predominant microbial, including Prokaryotes (bacteria and archaea).

Ediacaran biota:

Around 635-541 MYA, in late Proterozoic Eon first simple multicellular organisms appeared known as Ediacaran biota. Ediacaran biota was soft bodied and had various body structures.

Strange creatures of Cambrian Seas:

Cambrian seas filled with bizarre; several most famous creatures of that era are as follows:

Anomalocaris: Growing up to three feet long, it boasted stalked compound eyes, a pineapple-ring mouth, and two spiked, undulating frontal arms used to snatch prey.

Opabinia: it was a small, soft-bodied animal with five eyes and a single, long proboscis ending in a grasping claw used to pass food to its mouth.

Hallucigenia: It walked on seven pairs of slender, tube-like legs and sported rigid spines along its back.

Wiwaxia: A spiky, snail-like creature covered in overlapping, scale-like armor. It lacked legs and crawled on a muscular foot, grazing on the seafloor.

Pikaia: This small, eel-like swimmer possessed a notochord, making it an ancient ancestor to all vertebrates, including humans.

Trilobites: These highly successful, heavily armored arthropods dominated the seafloor. Ranging from tiny specks to over two feet in length.

Scientific debates and unanswered questions:

1. what triggers the Cambrian Explosion?

2. was it really an “Explosion “?

3. why did so many body plans appeared?

4. where are the ancestors?

5. why did some bizarre creatures disappear?

   what can the Cambrian explosion teach us today?

   It reminds us that nature is full of surprises. Even after hundreds of millions of years, we are still learning how life on Earth began and changed over time.