10/24- 
Why We Get Sick 
Chapters 5 and 6

These chapters are about things that cause disease in out environment, and 
how we are adapted to them (or not). 

Chapter 5 is about Injury. 
There are many ways that we are evolved for dealing with the possibility 
of injury.
 - avoidance, fear, learning (psychological things)
 - learning and understanding is discussed at length
 - repair- blod clotting into a scab, inflammation
 - pain- both psycholgical and physical
Some things that cause injury-
 - burn or frostbte
 - radiation


Chapter 6 s abot toxins. It distinguished between natural and artificial 
toxins. Natural toxins, of course, we have been exposed to over evolution 
and may be adapted to.

Many natural toxins come from plants. Plants have evolved them to combat 
animals that eat them (herbivores). We have countless adaptations to 
toxins, like avoidance, expulsion, stomach acid, enzymes, our liver, 
kidney, etc. We have also evolved defenses like cooking our food or 
otherwise processing it (smoking, salting, fermenting), and we have done 
selective breeding of domesticated plants and animals.

Artificial toxins, often we have no enzymes to break them down. We have no 
instinct to avoid them. Many natural toxins are present at such high 
levels now that they are basically artificial, like alcohol and other 
drugs, and addictions to these things are a sign of lack of adaptation to 
them.

Mutatgens and teratogens are toxins that are distinguished by their 
long-range effects- they may not hurt us now but they may kill us in years 
or decades. Avoidance of these things must be evolved. We are particularly 
vulnerable to artificial mutagens and teratogens.