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Humans Evolved from Four-Legged Creatures Similar to Squirrels

I enjoy writing about a wide variety of topics that draw upon my decades of life experiences. I hope you enjoy reading my articles.

One of my pastimes during the spring 2020 COVID-19 shutdown, when time was so abundant, was watching and feeding squirrels that frolicked on my back deck. With so much time on my hands, I started thinking about my existence and how humans actually evolved on Earth. We obviously evolved from sea life and four-legged creatures long ago, but what creatures did we actually evolve from before two-legged apes started appearing on Earth? One of them I surprisingly found was a squirrel-like creature that lived on Earth many millions of years ago.

Human evolution from cellular lifeforms to modern humans

Human evolution from cellular lifeforms to modern humans

Early Evolution of Life and Animals on Earth

Life on Earth first developed in sea vents approximately 3.8 billion years ago. This primitive ocean life developed from DNA/RNA into single-cell organisms by approximately 3.5 billion years ago and viruses by 3.0 billion years ago

Between 3.0 billion years ago and 2.15 billion years ago oxygen started accumulating in the Earth’s atmosphere. Scientists have found evidence dating back 2.15 billion years of cyanobacteria that used photosynthesis. Photosynthesis is the process by which living things use sunlight and carbon dioxide to create energy, with oxygen being created as a result.

900 million years ago, multi-celled organisms developed. By 800 million years ago most life was sponges living in oceans.

Although some millipede type of animals briefly made the move from the oceans to land 530 million years ago, massive and permanent migration of animals from the oceans to land occurred between 440 to 410 million years ago.

Humans evolved from a small furry mouse-like mammal that lived in trees and bushes 160 million years ago.

Humans evolved from a small furry mouse-like mammal that lived in trees and bushes 160 million years ago.

Mouse-like Creature That Humans Evolved From

Juramaia sinensis was a small furry mouse-like mammal that lived in trees and bushes 160 million years ago in the area that is presently northeast China. This was during the Jurassic era (201 to 145 million years ago), which was the era in which dinosaurs were the primary species on Earth.

Juramaia sinensis is the first known placental mammal that gave birth to live young, which are known in scientific circles as eutherians or placentals. Humans are placental mammals that are descendants of the mouse-like Juramaia sinensis.

Cretaceous–Paleogene Mass Extinction Event

The Earth has gone through several explosions of life in which numerous species appeared, such as the Cambrian explosion 541 million years ago. Earth has also experienced a number of mass-extinction events that wiped out many of the species that lived on the planet, such as the Cretaceous–Paleogene extinction event that wiped out non-avian (non-airborne) dinosaurs 66 million years ago.

The most important extinction event as far as mankind’s evolution is concerned was the Cretaceous–Paleogene mass-extinction event that wiped out all of the dinosaurs 66 million years ago, except for the ones that evolved into modern bird species (the birds you see every day are descendants of dinosaurs). Scientists are still debating whether dinosaurs went extinct due to a massive meteor impact or due to the changes in climate that followed the meteor impact. Whatever the reason, when dinosaurs stopped roaming the planet, mammals became the dominant species on Earth.

A tiny tree-dwelling squirrel-like primate called Purgatorius is an ancient human ancestor.

A tiny tree-dwelling squirrel-like primate called Purgatorius is an ancient human ancestor.

Squirrel-like Creature That Humans Evolved From

One of human’s ancient ancestors was a tiny tree-dwelling squirrel-like primate called Purgatorius, which is the oldest known primate to live on Earth. These creatures lived during the Paleocene approximately 66 to 56 million years ago, which was just after dinosaurs went extinct. With dinosaurs gone, our ancient primate mammal ancestor Purgatorius thrived.

I’ve found it amusing to watch squirrels run around in their quirky way knowing that we evolved from a similar creature that lived many millions of years ago in northeast China. Hard to get one’s mind around it, but it’s true.

Intermediate Species in Human Evolution

Between our squirrel-like ancestor Purgatorius and the appearance of modern humans (Homo sapiens), there were a number of four legged species, then monkey species, then ape species that evolved and eventually led to Homo sapiens and a number of other hominid species. As defined by the Oxford’s English dictionary: hominids are a primate of a family (hHominidae) that includes modern humans (Homo sapiens) and their fossil ancestors and also (in recent systems) at least some of the great apes.

Humans Are the Only Surviving Species Among Hominids

Modern humans are descendants of a hominid species that lived alongside two other hominid species in Africa starting approximately 2 million years ago.

Eventually, modern humans outlived their competitor hominid species. The last one to survive were Neanderthals, who went extinct in Europe about 40,000 years ago as the most recent ice age and competition with modern humans limited their food supplies.

With modern humans the only surviving hominid species, we have dominated the Earth for tens of thousands of years. Due to increasingly dire global warming, overpopulation, depletion of life-supporting resources, and the ever-present threat of nuclear annihilation, many are wondering how much longer Homo sapiens will exist on Earth?

Incredible Animation Shows How Humans Evolved From Early Life

Future Human Evolution Poll

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 John Coviello


Doris James MizBejabbers from Beautiful South on November 19, 2020:

John, I think you've done a great job here. The photos and graphics are great. According to Dr. Samir Osmanogich, a proponent of the Bosnian Pyramids, skeletal remains of a woman found at the pyramids were carbon dated to be 2 million years old. Dr. Sam, whom I've met in person, is receiving a lot of flack from other scientists about that. I thought that might interest you.

Anyway, I wonder if the discovery of Juramaia sinensis led to the age old question "are you man or mouse?