Question

1. Life on Earth was pretty simple for over 3 billion years.... then suddenly, around 530 million years ago, a huge diversity of animal forms suddenly (~10 million years time) appear in the fossil record. What might have caused animal forms to appear form?

2. 20% of all animal species are beetles! New species of animals are still being found, mostly invertebrates. How many species do scientists believe are out there?

Answer 1

Ans 1) In the sudden phase of evolution, it was seen that there was a leap from single cell simple organisms to multi-cellular animals. For billions of years, the single celled creatures dominated and the most likely the cells started organizing themselves into 3-D structures where the single cells combined together. They began to divide and grow. Nearly 530 million years ago first traces of animal life was seen known as Cambrian explosion. It is found that the prototypes for every animal body plan started to form and evolve accordingly. According to the molecular data, it is found that the first ancestors of animals are Urmetazoan which includes the chaonoflagellates that are microscopic aquatic organisms which are the closest ancestors of animals. It was the commitment and requirement of the cells to mutually benefit each other that led them to stick together and form multi-cellular organism leading to development of animals. The single cells came together and shared oxygen and food leading to development of bigger mass in form of body parts. It was also due to the changing ecosystem and environment that lead the single cells to come together and form multi-cellular organisms leading to formation of animals. One of the main reasons that might have increased the formation of complex multi-cellular organisms is the increase in oxygen concentration which could readily diffuse into organisms with multiple layers of cells. This led to changing ecosystem and hence development of more complex body plan.

Ans 2) It is actually very difficult to determine how many species are exactly there with new species being discovered every while. According to some research finding and data, it is estimated that there are nearly 8.7 million species that exist on the planet. Despite counting everything that is present in the central database it is still assumed that description of around 86% on the Earth and 91% species in the ocean dp not have a proper description.