Lamarck
Regarding Roland on Darwin, I am happy to see Darwin honoured in the blog. But it does not do proper justice to Charles Darwin to put him “next to Lamarck”. There were various ideas floating about, regarding evolution before Lemarck’s, in particular from Charles’ grandfather Erasmus. They were surely discussed at the Lunar Society. It was well known that animals changed a bit from generation to generation. The English country gentry were particularly interested in breeding the dogs and horses they needed for chasing foxes. Early geologists, particularly William Smith recognised that the world was much older than the Bible supposed, and that different animals had existed at different times.
The problem was to explain how evolution worked. Although unaware of Mendel’s work on inheritance, Charles Darwin got this right in considerable detail. Lamarck got it wrong. He would have said that fast horses had fast foals due to their training, rather than their genetics. In modern times, we can see that Lamarckian evolution happens not regarding species, but in another area. Clever mothers tend to have clever children, partly due to genetics, but also due to their education. Perhaps Alfred Wallace could almost claim a place next to Charles Darwin.
Incidentally, I read an article about William Smith in the National Geographic Magazine that painted a picture rather different from that in wikipedia. From humble beginnings, he made 2 or 3 fortunes, using his geological knowledge to plan canals. Each time business had a downturn, his money ran out quickly.
Upright Stance
I believe that Roland’s views of the development of mankind have some inaccuracies.
I am fairly sure about what follows, but will be happy to be corrected where wrong.
Genetic analysis seems to show that our common ancestor with chimpanzees and bonobos lived 6 or 7 million years ago. But there is still debate about this. Until recently, people, with typical human hubris, assumed that this common ancestor was fairly similar to these apes, while mankind had continued to evolve rapidly. But recently, very old fossil footprints have been found, which indicate that the common ancestor of chimpanzees and humans walked upright. The knuckle walking of the apes must have developed later, presumably due to the jungle environment. (Fossil remains of apes are even rarer than those of hominids, because the jungle environment does not tend to preserve them).
Aquatic Period
It is not known that hominids were ever largely aquatic. I have heard of this theory as the reason for having little body hair, but find it dubious. I doubt whether hominids spent much time in rivers and lakes in Africa, which were full of crocodiles. They would have survived better by the ocean shore. But there are other possible reasons for loss of body hair, for instance that parasites cannot then hide so well. Many aquatic mammals have hair (e.g. otters). The most recent theory about our upright stance is that it evolved for climbing in big branching trees. Orang-utans climb trees like people do. When they walk, they do it rather like people too.
It is wrong to say that the evolution of humans began 8 million years ago. It began 500 times earlier, with the first life on Earth. It is arbitrary to regard development of an upright stance as particularly significant. Lots of animals do it. There is little evidence that our ancestors lived in the jungle. Most mammals can swim a bit; why not hominids?
Africa the cradle of mankind
Africa is the cradle of mankind, because two (or more) waves of hominids came from there. Homo Erectus spread round the Earth from there. Much later Homo Sapiens spread from there too and seemed to replace them. But the picture is complex and uncertain. New scraps of evidence keep being found. Recently it seems that “Lucy” was not nearly our ancestor. A few years ago, Homo_floresiensis was discovered, which is probably a different species from modern man, and may have survived until 12,000 years ago. Neandertal man lived next to modern man until 30,000 years ago. I am sure they had sexual intercourse together, but we now know that we got no genes from them. Any hybrid offspring must have been sterile.
So they constituted a different species. Their brains were slightly larger than ours; so there is little reason to suppose that they were less clever than Homo_sapiens then. They also showed a similar degree of culture. Early Homo sapiens also had brains slightly larger than ours. No similarly intelligent beings pre-dated homo, but the same cannot be said of homo_sapiens. In so far as intelligence can be measured, I would say that more intelligence has resulted from education, than was inherent in the genes. But an early attempt to raise children with absolutely no education finished with them all dead at an early age.
I find it hard to use the word “creature” for animals and plants. Can we not start to call them “evolutes”?
The story about high grass reminds me of a silly joke . It concerns the proud little people of the Fukawi tribe. They used to jump up and down in the tall grass shouting “we’re the Fukawi”!
Cooking
The story about cooking being needed for a large brain seems very dubious. Lean meat is rather short on calories. I think cooking was rather an adaptation for living where winter was hard. There would still be animals around to catch and cook, when the fruit was gone, and when roots were hard to get at under snow. (See http://www.rawpaleodiet.com/when-did-humans-begin-to-cook/).
Intelligence after Mankind
As far as I know, there is very little reason to believe that no intelligent life will follow humans on Earth. Roland, can you justify it? After the dinosaurs, it took perhaps 100 million years for similarly intelligent animals to develop. If some mammals survive the elimination of humanity, it may take a similar time for civilised beings to evolve, but with luck the Earth will remain fertile that long. Furthermore there is a fair chance that intelligent descendents of computers will preside over the elimination of mankind. That could happen in hundreds of years, rather than millions.
Eugenics
Of course intelligent beings can influence evolution positively. The main problem is to decide what is positive and what not! Better food plants, friendly cats, clever faithful sheepdogs, strong carthorses, and cows with lots of milk are positive? And what about smallpox being wiped out? Of course “intelligent beings” may also produce negative results. For instance living species are becoming extinct at a record rate. Human eugenics could surely also produce positive results. But here too are great dangers. Look what happens when a madman like Hitler tries to do it. Fears of modern methods of genetic modification of crops may be justified. If and when the computers take over, I hope they will be well programmed.
CW
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