3 Aspects of Humans and Evolution

1. 3 Aspects of Humans and Evolution

2. 3 Aspects of Humans and Evolution • Sickle Cell Anemia, Malaria and Evolution

3. 3 Aspects of Humans and Evolution • Sickle Cell Anemia, Malaria and Evolution • “The Red Queen” in action

4. 3 Aspects of Humans and Evolution • Sickle Cell Anemia, Malaria and Evolution • “The Red Queen” in action • Scars of Human Evolution

5. Sickle Cell Anemia • Genetic Blood disorder • Two forms, severe and mild • Severe form is often fatal • Blood clumps if oxygen levels are low • Damage to organs, etc. can occur

6. Sickle Cell Anemia • Sickle cell Anemia • Various Effects of Sickle Cell

7. Sickle Cell Anemia If sickcle cell anemia is so bad, why is it around anyway? And why, in parts of west Africa, is the rate of affliction so high that most people are afflicted?

8. Sickle Cell Anemia • Sickle Cell is Explained by Evolution!

9. “The Red Queen” The “Red Queen” is the idea in evolutionary biology that we are in a race with our predators and we have to keep evolving in order to stay alive. Our predators, at this time, are mostly microbes: viruses, bacteria, fungi and parasites.

10. “The Red Queen” “The Red Queen” comes from “Through the Looking Glass”. Alice runs as fast as she can, but seems to go nowhere. The Red Queen remarks: `Now, HERE, you see, it takes all the running YOU can do, to keep in the same place. The Red Queen

11. “The Red Queen” Two excellent examples of how human biology is connected with evolution and the race against predators are… • Tuberculosis, drug resistant strains • HIV – rapidly evolving (changing) virus

12. The Scars of Human Evolution Two Types … • Scars confined to individuals • genetic diseases • genetic deformities • genetic tendencies toward disease • Scars that we all have

13. The Quadrupedal Skeleton

14. The Human Skeleton

15. The Quadrupedal Spine

16. Human Spine

17. Lots of Problems in the Lumbar Vertebrae

18. Knee and Hip Problems

19. Prognathism and Tooth Room • Prognathism decreases from Australopithecus to Homo sapiens • The reduction of the mouth, left less room for the teeth. • Being catarrhines, we inherit 32 adult teeth.

20. Teeth Problems • The 3rd molar causes most tooth problems • Nine out of ten people have at least one molar that doesn’t descend • Those that do, often cause trouble

21. 3rd Molar Impaction

22. Evolution in Action • Traits that are undergoing strong evolutionary pressure are often quite variable. • Our dental situation is a case in point. After 20 million years with 32 teeth, we find ourselves in trouble producing so many!

23. Brain Size • Archaic humans and Neandertals both had brains bigger than the modern average. Even 100,000 years ago. • Is it possible that the long trend toward larger brains has reached an end? • What would put the brakes on selection for big brains?

24. Difficult Birth!!! • Other wild mammals typically have non-stressful birth of their young. • Humans are notorious for difficult and dangerous births. It is part of our deepest knowledge. • The mythology and folklore around childbirth indicates the point.

25. Human Evolution • Mutation and sexual reproduction produces variation • Natural (and cultural) selection is involved in who leaves offspring and how many • Each generation is genetically different than the previous generation • Over time, the species becomes different.