Alan Stahler: Tools and their uses passed on through generations |

Alan Stahler: Tools and their uses passed on through generations

Despite the retirement of Steve Davis at Seven Hills School, a multi-million-year tradition will continue.
Submitted photo |

I’ve been reading Ian Tattersall’s book, Masters of the Planet, a story of human evolution, and it’s got me thinking about how we live today.

Somewhere in Africa, some five-to-seven million years ago, a population of apes split apart: The descendants of one group, over millions of years, would evolve to become today’s chimpanzees. The descendants of another group, over those same millions of years, would evolve to become us.

We resemblance each other, people and chimps. Whereas most mammals have four legs, humans and chimps have two legs and two arms; we both have hands with five fingers; and fingernails, rather than claws (most chimps, I learned elsewhere, bite their fingernails).

People are also very different from chimps: We’ve lost our fur; our faces are flat; our teeth have shrank; so have our muscles.

And our brains have grown large. We’ve learned to use symbols, which we represent with words … we can think things over.

Thinking takes energy; large brains need large amounts of energy. One out of every five donuts (or whatever you eat) gets “burned” in the brain (that’s “burned” in quotes — but it’s still oxidation — combining fuel with oxygen for energy).

There’s not a whole lot of energy in leaves, or grass; grazers and browsers need to spend a lot of their time eating.

Meat is a high-energy food. But hunters like lions and leopards have strong muscles, long claws, impressive teeth. How could humans compete?

Perhaps by scavenging. After a lion had eaten its fill, and moved on, paleo-people could move in and finish up what was left. But meat rots quickly in the tropical heat.

If gorillas could be trained to play football, they’d be unstoppable … literally. Imagine a 250-pound linebacker trying to stop a 400-pound gorilla … ain’t gonna happen.

But a team of gorillas would have one serious disadvantage — they could not use the forward pass. No animal on Earth, other than humans, has mastered the art of precision throwing.

What if a band of scavengers did not have to wait for a lion to finish eating? What if they could drive the lion away from his kill — temporarily — by heaving stones at it? This is not ordinary scavenging, this is power-scavenging.

Throwing stones to hold off a hungry lion that’s already tasted blood is not something you’d want to do for long — you’d want to grab the meat and go.

Our ancestors made tools. Stone blades could quickly cut meat from bone. Other animals do use tools — chimps use blades of grass to fish termites from mounds — but no animal has taken tool-use as far as humans.

For a dozen-and-a-half years, Steve Davis has been teaching bicycle repair at Seven Hills School in Nevada City. Once a year, Steve and the kids bring re-built bikes, along with a mobile bike repair shop, down to the Sacramento food kitchen Loaves and Fishes, to give away the bikes and repair bikes that people bring in.

Now Steve is retiring, though the program he created at Seven Hills will continue. The program not only provides much-needed transportation to folks in Sacramento; it also furthers a multi-million-year human tradition: teaching the next generation how to use tools.

Al Stahler enjoys sharing nature with students of all ages. His science stories can be heard on radio station KVMR (89.5 FM), and he may be reached at

Support Local Journalism

Support Local Journalism

Readers around Grass Valley and Nevada County make The Union’s work possible. Your financial contribution supports our efforts to deliver quality, locally relevant journalism.

Now more than ever, your support is critical to help us keep our community informed about the evolving coronavirus pandemic and the impact it is having locally. Every contribution, however large or small, will make a difference.

Your donation will help us continue to cover COVID-19 and our other vital local news.


Start a dialogue, stay on topic and be civil.
If you don't follow the rules, your comment may be deleted.

User Legend: iconModerator iconTrusted User