By studying the genes of modern animals, scientists have been able to infer what the earliest animals may have looked like. These studies suggest that the first animals were likely simple, worm-like creatures with a simple body plan. They may have had a mouth, an anus, and a digestive system, but they would not have had any specialized organs or appendages.

The earliest animals are thought to have evolved around 600 million years ago. This was a time when the Earth was very different than it is today. The atmosphere was much thinner, and the oceans were much warmer. There was also much less oxygen in the atmosphere, which may have been a limiting factor for the evolution of complex animals.

Over time, as the environment changed and oxygen levels increased, animals began to evolve more complex body plans. This ultimately led to the development of the diverse array of animals that we see on Earth today.

Here are some of the key findings from genetic research on the earliest animals:

* The first animals were likely simple, worm-like creatures with a simple body plan.

* They may have had a mouth, an anus, and a digestive system, but they would not have had any specialized organs or appendages.

* The earliest animals are thought to have evolved around 600 million years ago.

* The environment was much different then than it is today, and oxygen levels were much lower.

* Over time, as the environment changed and oxygen levels increased, animals began to evolve more complex body plans.

This research provides us with a glimpse into the early history of animal evolution. It helps us to understand how the first animals came to be, and how they eventually evolved into the diverse array of animals that we see on Earth today.