The the first homind species (the ancestors of human beings) emerged about 2.5 million years ago. Fossil evidence supported by DNA analysis indicates that Homo Erectus emerged in Africa leading on to Heidelbergensis, Neanderthals, and the Denisovans around 500,000 years ago.
The display in the Morian Hall of Paleontology in Houston has the following list of human ancestors:
- Sahelanthropus tchadensis, 7 – 6 million years ago
- Orrorin tugenensis, 6.2 – 5.8 million years ago
- Ardipithecus kadabba, 5.8 – 5.2 million years ago
- Australopithecus anamensis, 4.2 – 3.9 million years ago
- Australopithecus afarensis, 3.9 – 3 million years ago
- Kenyanthropus platyops, 3.5 million years ago
- Australopithecus garhi, 2.5 million years ago
- Australopithecus africanus, 3.5 – 2.1 million years ago
- Homo habilis, 2.3 – 1.4 million years ago
- Australopithecus sediba, 1.95 – 1.78 million years ago
- Paranthropus boise, 2.3 – 1.3 million years ago
- Paranthropus aethiopicus, 2.7 – 2.3 million years ago
- Paranthropus robustus, 2 – 1.5 million years ago
- Homo georgicus, 1.77 million years ago
- Homo ergaster, 19.9 – 1.4 million years ago
- Homo erectus, 1.8 million – 300,000 years ago
- Homo antecessor, 1.2 – 0.8 million years ago
- Homo heidelbergensis, 800,000 – 300,000 years ago
- Homo rhodesiensis, 700,000 – 200,000 years ago
- Homo neanderthalensis, 500,000 – 28,000 years ago
- Homo sapiens idaltu, 200,000 years ago
- Homo floresiensis, 98,000 – 13,000 years ago
- Denisovan man, 40,000 years ago
- Homo sapiens, 200,000 years ago until present
The classical find of Lucy, our oldest identifiable ancestor, has recently been superseded by a skull of Australopithecus anamensis dating back about 3.8 million years ago. It appears that a number of Australopithecus species were co-existing at the time, yet only one line continued on to form modern day humans.
As recently at 50,000 to 100,000 years ago there may have been 5 or more Hominid species co-existing on this planet (including Homo Floresiensis in Indonesia), but Homo Sapiens emerged as the predominant and only surviving species in the last 20,000 years – see diagram below. It seems that Homo Sapiens interbred with at least Neanderthals, Denisovans and Homo floresiensis.
The scientific name for the current race of human beings is Homo Sapiens Sapiens (homo = human being, sapiens = wise person). Homo Sapiens seems to have been around for about 200,000 years or about 10,000 generations (one generation being typically 20 years). Each animal species is based on a set of genetic code in its DNA, and the DNA of human beings has about 3 billion genomes.
It has been noted that with each generation of human beings random mutations occur in the genome, and with each passing generation the original genetic blueprint is degenerating. Each species has a genetic lifetime, and some estimates are that the human race has only another 300 generations or 6,000 years before it is destined for extinction. Fortunately, scientists disagree on this rather pessimistic outlook. Most genetic mutations are degenerative, and it is very rare that a mutation results in the appearance of a beneficial trait. Within the next few hundred years it is likely that humans will develop either the scientific/medical knowledge to engineer our own DNA, or a natural genetic mutation will result in the gradual emergence of a new species or sub-species of humans that can continue the evolutionary path of hominids on this planet. This is how life has evolved on this planet for millions of years and it is likely to continue to do so. It is worth noting that other primates like Apes and Chimpanzees, and the other hominid lines (homo erectus, floresiensis, Neanderthal man) have died out without spawning a replacement genetic line.
Don’t worry; there is still plenty of time for us to achieve our potential and find our way to enlightenment. But it is good to consider the big picture and that the human race will not continue in its present condition forever. We should expect to see major changes within a few thousand years, and perhaps within a few hundred years due to our own efforts to change our genetic code.
As a species, Homo Sapiens Sapiens have been around for probably about 200,000 years (possibly as long as 400,000 years), during which time our DNA has been degrading (as it does with all species). Some estimates are that we have only another 300 generations (about 6,000 years) before the human race either evolves or mutates into something else/better, or dies out due to a predominance of biological weaknesses. Extinction seems unlikely. Within the next 100 to 200 years we may well have developed genetic engineering to such an extent that we can choose to evolve in to whatever we want.
Evolution or devolution?
One view is that the first human beings were pure and perfect (in biblical terms, we were living in the Garden of Eden). Since that time each generation has seen compounding genetic mutations which has “spoilt” that original DNA pattern. Successive generations with ever-increasing numbers of human beings have continued this process of degeneration. This is used to justify what seems to be increasing numbers of people born with physical conditions and mental problems (such as autism), and increasing susceptibility to diseases such as cancer, dementia, etc. The early humans in the bible were said to live for about 1,000 years (though this may not be literal human years) in the Garden of Eden.
There is no proof that the original humans were perfect. Evolution has shown that we came from the same ancestors as modern day chimpanzees and apes, and fossil evidence suggests that a few million years ago the human ancestors looked much more ape-like. The Neanderthals had brain capacities larger than modern day humans but there is no evidence that they were more intelligent than the Homo Sapiens of the same period. Early hominids may have been better adapted to the environment of that time than modern humans, and may have suffered less from cancer and autism, but the average life expectancy was likely to have been less than the current 70 or so years in western countries.
In biology there is no such thing as devolution. Evolution continues to occur with the characteristics of certain individuals rendering them more suitable to survival in changing environmental conditions. If planetary temperatures continue to rise then perhaps our successors will be better adapted to the environment in which the dinosaurs flourished for tens of millions of years.
It has been suggested that the creatures described as Yeti, Yowie, Bigfoot, Sasquatch, etc are human beings that have regressed or devolved. Baird T Spalding wrote of the snowmen in the Himalayas in his famous books The Life and Teachings of the Masters of the Far East. Sadly, there has been no confirmed sightings or study of a captured individual to prove this. Recent tests have confirmed hair samples from the Abominable Snowman to come from bears. Such devolution is likely to require many generations – it certainly doesn’t happen within one generation.
There is no doubt that over the last few hundred years the medical and technological advancements demonstrate that we are making mental evolutionary progress. At the same time, some believe that society is losing its moral values – respect for elders, the traditions of the family and nation, declining religious memberships, etc. This may actually be a shift in the percentage of people in the Absolutist vMeme (see discussion on Clare W Graves vMeme model for the human race later). The good news is that there is less cannibalism around, and fewer sacrifices of animals and human babies than in the past, which I propose is an improvement in moral values.
See also the spectrum of theories regarding evolution.