Evolution gone wrong The curious reasons why our bodies work (or don't)

Biologist Bezzerides speculates about why evolution would select for anatomical imperfections and possible problems for the human body. The size of the human jaw has been shrinking since the origin of our species, and increasingly, teeth don't fit quite right (hence the need for braces or extraction of wisdom teeth). Walking on just two feet (bipedalism) was a major milestone for our early ancestors, but our modern musculoskeletal system now pays a price with knees prone to injury, low-back pain, and changes to our feet that have left them less flexible. The anatomic proximity of the esophagus and trachea creates a risk of choking. Bezzerides contends that evolution has in some ways been "error-prone" in regard to the design of the human body. Fair enough. But evolution is a process that plays out over very long periods of time, and we're not finished evolving. Bezzerides observes that anatomic, behavioral, and physiologic "trade-offs" are part of how it does business. And evolution can hardly be blamed for cultural influences adversely affecting the body, such as staring at screens nonstop.