The Story of the Human Body: Evolution, Health, and Disease, by Daniel Lieberman

1. We are still evolving. the most potent form of evolution is not biological evolution of the sort described by Darwin, but cultural evolution of the sort we develop and pass on new ideas and behaviors.

 

2. Research in these fields is changing fast. Inevitably some of what I include will become out of date. I apologize.

 

3. We didn’t evolve to be healthy, but instead we were selected to have as many offspring as possible under diverse, challenging conditions.

 

4. More than 600 generations ago, everybody everywhere was a hunter-gatherer. Agriculture was invented 10,000 years ago.

 

5. Evolution is simply change over time.

 

6. Natural selection process is the outcome of three phenomena: variation, genetic heritability and differential reproductive success.

 

7. your height is much more heritable than your personality, and which language you speak has no genetically heritable basis at all.

 

8. Relative fitness happens whenever individuals with heritable variations differ in the number of surviving offspring they have compared to other individuals in the population.

 

9. Your genome is a sequence of about 3 billion pairs of molecules that code for slightly more than 20,000 genes.

 

10. A third of your genome has no apparent function.

 

11. Like a palimpsest, a body has multiple related adaptations that sometimes conflict with one another, but at other times work in combination to help you function effectively.

 

12. Many human adaptations did not necessarily evolve to promote physical or mental well-being.

 

13. Humans are adapted for having as many children, grandchildren and great-grandchildren as possible.

 

14. Before our ancestors were hunter-gatherers they were apelike bipeds, and before then they were monkeys, small mammals and so on.

 

15. We even promote mismatch diseases by treating their symptoms so effectively that we unwittingly perpetuate their causes.

 

16. By becoming upright, humans emancipated their hands from locomotion, freeing them for making and using tools.

 

17. Laboratory studies that have enticed chimps to walk on treadmills while wearing oxygen masks have found that these apes spend 4 times more energy to walk -on either 2 or 4 limbs- a given distance than humans.

 

18. We often say “you are what you eat” but evolutionary logic dictates that sometimes “you are what you’d rather not eat”.

 

19. Human cheek teeth are actually bigger and thicker than those of chimps.

 

20. The evolution of large external noses in early Homo is strong evidence for selection to walk long distances in hot, dry conditions without dehydrating.

 

21. Your guts have about 100 million nerves, more than those in your spinal cord or your entire peripheral nervous system.

 

22. Homo erectus’ bodies sort of resembled your family’s from the neck down. Their brains would be much smaller and their large, chinless faces would be topped by massive browridges perched in front of long sloping foreheads.

 

23. The oldest H. erectus fossils so far unearthed come from Kenya and date to 1.9 million years ago. The oldest fossils outside of Africa currently come from a 1.8 million year old site from Georgia between the Caspian and Black Seas.

 

24. H. erectus is thus the first intercontinental hominin, although some have speculated that H. habilis also got out of Africa.

 

25. Dispersals occur as populations expand without increasing their destiny.

 

26. Ice Age as a period when vast glaciers covered much of the planet was by repeated cycles of extreme cooling when glaciers expanded, followed by rapid warming in which they contracted.

 

27. Populations in Africa were not directly affected by glaciers.

 

28. There is no consensus on exactly how many species descended from H. erectus, and who begat whom.

 

29. The African lineage evolved into modern humans. Another lineage evolved into the Denisovans in Asia, and in Europe and western Asia the most famous species of archaic Homo evolved, the Neanderthals.

Daniel Lieberman


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