What Comes After Homo Sapiens?
by Don Simborg
This book is intended for curious readers of nonfiction. A lot of science and technology is discussed, but my intent is that you need not be a scientist or technologist to understand and enjoy it. My goal is to generate discussion. Below are brief excerpts from each of the chapters.
1 The Questions
What comes after Homo sapiens? When will that happen, and what will that new species be like? Those are the questions. Before I can even begin to discuss the answers, I need to spend time defining these questions and my process for getting to the answers; otherwise, the answers will be meaningless to readers.
2 Taxonomy
Did King Philip Call Out For Good Soup? That’s one of the many mnemonics people use to remember the taxonomy of living things like plants and animals: domain, kingdom, phylum, class, order, family, genus, species. Our focus is on the bottom of this massive classification system of all living things, species. You can’t say what something living is without stating its species. The great geneticist of the early twentieth century, Theodosius Dobzhansky ...
3. Species
What exactly is a species? It is a question that has been debated at least since the time of Plato, Aristotle, and other ancient Greeks...This difficulty in defining species is appropriately referred to in the literature as the species problem...“There are almost as many concepts of species as there are biologists prepared to discuss them”...Has the species problem been solved by DNA analysis? No...Is there an official list of species? Yes, many of them—and they all differ from each other...there is a tension between lumpers and splitters...Ernst Mayr...Kevin de Queiroz.
4. Speciation
If and when Homo nouveau appears on earth, it will do so through a process called speciation...Whereas species may only be a concept, speciation is real...Ultimately, speciation must involve genes...“the process of speciation involves acquiring reproductive barriers"...This next discussion usually begins with reference to Darwin’s On the Origin of Species...Natural selection works both positively and negatively...We aren’t very big, don’t run very fast, can’t fly, can’t swim very well, and aren’t very strong compared to lots of predators out there. Our brain functions were selected to overcome all of that and allow us to live long enough to make babies...Just as there remains fuzziness in the concept of species, there also remains fuzziness in the concept of speciation.
5. Genetics
It wasn’t until the mid-to-late 1800s that Lamarckian evolution was debunked and humans realized that there were discreet “units” of heredity that get passed on between generations...This was based on Gregor Mendel’s work with peas...genes... phenotype... genotype...epigenome...Human Genome Project...alternative splicing...I told you this was far more complicated than Mendel’s peas...I will come back to some of the details of genetics when I consider the various mechanisms that might lead to Homo nouveau.
6. Getting Past the Chimps
To prepare for the possibility that Homo nouveau will emerge from Homo sapiens, it is useful to review how Homo sapiens got here... We don’t really know for sure how we got here...fossil evidence is fragmentary ... paleontologists have done an amazing job in reconstructing much of our lineage...So what exactly does it mean to describe chimps and bonobos as our closest relatives?...Somehow in this milieu, a group of about thirty thousand individuals started to spend more time out of the trees and began an amazing evolutionary journey. They became the first humans.
7. Getting to Humans
The story is neither pretty nor clear...There were lots of Leakeys...After the chimps split off from the other hominids 5.4 million years ago, our ancient ancestors moved out of the trees and eventually away from the forests of Africa, onto its more open plains. We developed a more upright posture and a bipedal gait...We have the only brain that can even ask the question about brains... But why didn’t the chimps also develop a large brain?...After Ardi came Lucy, evolutionarily speaking...Why bipedalism?...There is no debate that Homo erectus, which lived from 1.8 million years ago until 50,000 years ago, is human. Its brain was larger...
8. Out of Africa
Until about 1.8 million years ago, all of the humans on earth were in Africa. For whatever reason—whether in search of better food sources, seeking freedom from conflict and predation from other species, or simply the curiosity and wanderlust of an imaginative brain—a small group of Homo erectus humans made their way into the Middle East and Western Asia...Discussion of Homo heidelbergensis is often referred to as the “muddle in the middle"...exactly what changed between our immediate predecessor and Homo sapiens in Africa that warranted declaring us a new species... Neanderthals ...Denisovans...why didn't they ethnic cleanse us?
9. How Might Homo Sapiens Evolve?
I am now ready to think about how Homo nouveau might arise...the process of going from a chimp-like ancestor to Homo sapiens took millions of years and dozens or more side trips to oblivion...but we will be able to make the call when Homo nouveau has arrived...At this point, I am leaving the realm of facts and history as best I can know it and am heading into speculation. However, it will be speculation based on this history. The intent is to create not a science fiction story; the intent is to speculate based on science. I will be trying to extrapolate from what we know, not deviate from it.
10. Catastrophe
After every mass extinction (and there have been five), many species that survived recovered in population and evolved…In fact, we are one of them...We know of no instance where one of the millions of species wiped out sixty-six million years ago has reemerged from total extinction...The whole point of this book about our recognizing Homo nouveau becomes moot in the face of a catastrophe that wipes us out..a dark-winter catastrophe...Their conclusion is that our clever Homo sapiens would figure it out... Any of these global changes can and probably will happen again over millions of years.
10. Natural Selection
Now we’re talking about speciation the old-fashioned way: by slow evolution and natural selection rather than a more dramatic catastrophe...We have now gone another two hundred thousand or so years since Homo sapiens emerged and about fifty thousand years since we took over the world (at least in our own minds)...Something in our genetic makeup is working right...The possibilities are limited only by imagination...My bias is that any future speciation by natural selection will be related to something changing in the way our brain is wired or functions...We have learned so far that the human brain is more complicated than any tools Homo sapiens have ever invented, including our most complex computers...it is difficult to define our unique brain phenotype...If you think I’m now in the realm of science fiction, you need to have your brain rewired...What a piece of work is man!...Natural selection is not a conscious decision...Perhaps we have maxed out on the survival advantage of intelligence.
11. Genetic Engineering
We may not want to wait for natural selection to create Homo nouveau... Homo sapiens has been genetically modifying plants and animals for thousands of years, probably dating back at least twelve thousand years... At the DNA level, we are all alike; we are the same as a pea, a bug, or a worm in that regard. We use the exact same four nucleotides and the same three-digit codes to go from nucleotides to amino acids; our proteins consist of the same twenty amino acids, and our DNA has the same double helix structure. It is only in the sequence of the nucleotides that we differ... recombinant DNA...Paul Berg...The implications of this early work were revolutionary...This has not been without public controversy and political debate...I am going to spend some time discussing the possibility of gene therapy to cure genetic disease...OMIM...It is clear that the early bloom is off the rose for gene therapy...The potential benefits of germline therapy are irresistible...Enter CRISPR... once germline gene therapy becomes routine and ubiquitous—and I’m confident it will one day—lots of things could happen intentionally and unintentionally that could lead to Homo nouveau.
13. Electronic Evolution
Are viruses alive? This question is relevant because our presumption is that Homo nouveau will be a living species, and some of the discussion related to electronic evolution will raise that question...Computer technologies will become much more integrated into our physiology and how we function from minute to minute...Where all of this connectome work is heading is to be able to simulate in a computer the functioning of the human brain...The difference is common sense. People have it; computers don’t. Will we understand common sense from the connectome?...Ray Kurzweil thinks we’ll get there faster than I do...Singularity...2045...Why would an ASI want to harm us?...existential threat...Is a cyborg with vastly enhanced intelligence because of embedded nanobots a new species?...We can create robots to assemble parts of automobiles, but we can’t build one to safely bathe your baby or correctly sort your laundry... I have spent a great deal of time on the subject of electronic evolution.
14. The Answers
You'll have to read the book. But you can continue the journey here.