Did you know that we are all related? Yes, we are all family. The human genome project has revealed to us long ago that there are no genetically distinct and pure groups of humans. We are all cousins.
The Tree of Life
The concept of The Tree of Life, in many of our world’s myths and legends, conjure symbolic imagery of a magnificent and beautiful tree. In The Bible, we are told that the first humans were disallowed to eat of its eternal fruit.
Today, we also have a Tree of Life but it is not forbidden to partake of it. It is the Tree of Biological Life. It is the only Tree that serves to show humanity’s true Earthly origins and the origins of all species on this planet.
But before we argue evidence of our global kinships, let’s talk about family trees.
A family tree shows your relatedness to others in your family. If you have ever seen a family tree, you may have noticed the branching.
Image Source: familyholiday.net
Common ancestors, such as granddad and granny, can give rise to many offspring, who then create offspring of their own. Each of these offspring share similarities because they all come from the same common ancestry. Though they have similarities, each also have various genetic mutations and variations that give rise to recognizable/visual differences. Most mutations appear benign, some are deadly but some of these genetic differences may be beneficial. These changes may decide the fate of a race or cline of humans. Example: Mutations that help some humans resist the Black Death and HIV.
Image Source: geneticliteracyproject.org
Constantly Changing and Evolving
The same pathogens that once plagued our ancestors may not affect us now due to small modifications of our genetic code. When your parent’s genetic material combined to eventually create you, some traits were lost, some acquired, and some recombined. You have become a unique individual!
Now, imagine if this mixing of genes and mutations occurred for a million years; in the end, the resulting offspring wouldn’t look very much like their Great-grandfather x 10,0000.
Image Source: primatetales.com | Hominid Skull Comparison
It’s beautiful to be able to look at your body and see the result of these slow changes. You are witnessing your evolutionary lineage. Thanks to the discovery of DNA, and more modern ways to interpret and understand our world, we now know more than ever about our evolutionary past!
Invasive Evidence of Evolution
Most of us have experienced a cold or flu. These are caused by viruses. Many viruses find their way into your body and start causing damage before they are eventually destroyed and flushed out of your system. However, some viruses find a way to be passed down to the next generation! How?
Within our DNA are remnants of an invasion, a viral invasion that occurred to our ancestors long ago. These viruses invaded our sex cells and wrote its code into our DNA. Luckily, thanks to the miracle of imperfection, when some of these infected cells replicate, they produce small errors in the code of the virus. When this occurs, the virus becomes inactivated and is passed down to future generations without causing harm to the host, hopefully. These are called endogenous retroviruses (ERVs).
Why is this important and evidence for evolution?
Well, ERVs are primarily passed on via reproduction. So, just like a mom passing down her blue eye color to her child, ERVs can be transmitted in the same way; thus, if a scientist finds the same “viral remnants/viral genetic sequence” in another organism it can be assured that they share a recent common ancestor and are cousins.
Imagine if you found a species of hamster in one valley and a different hamster species in another valley a hundred miles away. The question of relatedness would be easy via other genetic means, but the number of shared ERVs can assist with when the ancestral split occurred.
In Chimpanzees, we share many ERVs with them! These ERVs match almost exactly with ERVs found in us. Remember, ERVs are passed down from parent, to offspring. No! This doesn’t mean that a chimp and human had babies! But this is does conjure the question: How is it possible that many apes and humans share many of the same ERVs? The answer is simple, we must share a common ancestor that at one time contracted this virus. We are cousins, with all modern apes and primates. We share a common ancestor in the Grand Tree or Web of Life.
It has been argued that ERVs could have entered the human line through some other means. Though this is true, it’s difficult to explain away how that particular ERV genetic sequence matches human ones so closely and how the molecular sequencing matches a timeline that fits the paleontological evidence.
The Citrus Problem
In another example of obvious descent with modification, is the fact that humans and apes both cannot produce Vitamin C naturally. Most other mammals can produce Vitamin C on their own, (accept the Hamster and some other rodents). As a result, Apes and Humans have to acquire Vitamin C from outside sources, fruits, etc. What happened? Why would apes and humans have this same problem? It turns out, that when we look at the genes, that not only has something gone wrong with producing Vitamin C, but that our Ape cousins have the same broken gene as humans. Our common ancestor at one time lost the ability to produce Vitamin C, and passed that trait down to us. Our hamster cousin? Well, the genes that would help him manufacture Vitamin C have changed and are broken too, non-functioning for the task of Vitamin C making. But, the hamster’s Vitamin C gene is broken in a different place. Exactly what evolution would predict!
Okay, but what does this have to do with cousins and families and all that?
Image Source: familyoriginstree.com
We are getting there. The pic above shows a Tree of Life, using DNA relationships only. This is significant because if we had these samples and were completely ignorant of their origin, the tree would still be represented this way. The evidence speaks for itself. We share a common lineage with all Great Apes and each other. Humans then, of course, share many more ERVs, which matches evolutionary theory perfectly.
The relationships should be clear at this point, but let us look at one of my ancestors, David Day, in another Tree of Life depiction.
Image Source: familyoriginstree.com
Notice that it’s the same pattern. It’s the same distribution you’d expect in a ‘modification with descent’ scenario. David is the root and the children are the branches, different from him, but similar. Those children then start their own branches, their offspring are also different yet similar as well. It never ends! Allow a few million years of this branching and voilà, different but similar looking creatures result. Give another 10 or 100 million years, organisms begin to look hardly related to their ancient great-grandparents. (As evidenced via the fossil record)
Image Source: https://hcnaturalselection.wikispaces.com
All life on Earth is part of an amazing evolution that goes back 3.5 billion years. Millions of Earth’s creatures all descended from one or two primitive forms generating the variety we see today. For humans, our evolution is relatively recent. This is why we look very much alike. We have a few regional differences but we are still very much the same species. As we all have descended from a common ancestral line, ipso facto, we are all cousins!
I wish humanity would realize that, in comparison to the vastness of the Universe, our home is just a tiny speck of dust floating in space. All of the people and creatures that live here are our family. Yet, we fight as if we have no other recourse. We hate as if hate is something to value. We kill as if life means nothing. We despise knowledge as if it’s a virtue. We love, only when convenient.
I think. We can do better. We must be better. We are one global family. We Are All Cousins in this Grand Tree of Life.
2008: The Great Tree of Life, Leonard Eisenberg
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- Montel-Hagen, A., Kinet, S., Manel, N., Mongellaz, C., Prohaska, R., Battini, J.-L., Delaunay, J., Sitbon, M. & Taylor, N. (2008) Erythrocyte Glut1 Triggers Dehydroascorbic Acid Uptake in Mammals Unable to Synthesize Vitamin C. Cell. [Online] 132 (6), 1039–1048. Available from: doi:10.1016/j.cell.2008.01.042 [Accessed: 31 December 2011].