It might be funny, but since geology is mainly about rocks, I think it's fair to say that the first creatures working with rocks were basically the first geologists. They have learned what rocks are good for different tools or activities along the way, but the start was random for sure. It's our life story- we don't know how much we love rocks until we are not bumping into them. This is how it starts, then becomes like a drug. You just need to know more...to have all of them:))). I am sure their views about the subject were quite different, but something triggered this need of using rocks as tools.
But coming back to them as individuals, who were they exactly?
Rocks and bones
Around 3.4-3.3 million years (Ma) something happens in the Great rift Valley in Africa and early hominins became fascinated with rocks. They were the first in the "knapping guild" with evidences from multiple sites around Turkana Lake (Kenya, Ethiopia) and Danakil Depression in north (Ethiopia). Previous tools were attributed to the earliest genus of homo-Homo habilis (the handy man), but this species is much younger- 2.6 Ma. Luckily, at Lomekwi, in Kenya, a series of fossils were found in the same beds with some tools, remains attributed to Kenyanthropus platyops. This is the more amazing because K. platyops it's a very early hominin, pushing back the boundaries of the hominins concept itself.
Various tools found at Lomekwi 3 site (Harmand et al., 2015)
Replicated experiments have shown that Lomekwi knapping was intentional and not random. How it occurred first time though, no one knows. Probably someone was bored and started hitting various rocks and noticed they can break in different shapes. Maybe they got hurt doing it and realized this could be inflicted on other animals in order to provide food easier...We can't know exactly, but we know that sharp tools were used on bones from Dikika (Ethiopia) around 3.3 Ma.
I remember a funny story since I was a student. We were on the field with the faculty in a mining district. In one of the days, a very bored colleague was hammering randomly every rock he could find, without even looking. At a certain point a boulder cracked open to reveal "the largest wolframite crystal" our teacher saw in his life, so my colleague got the maximum grade for free. :))) I imagine that a random case like this sparked the attention of the early humans, becoming in time a useful habit.
A changing world
Pliocene, the time period when these tools were shaped, is a transition period and it follows after a much drier Miocene. During late Miocene Sahara desert forms and the Mediterranean connection to the Atlantic is obstructed, forcing the water to evaporate nearly to dryness. Later on, around 3 Ma, ice caps started to grow again, enhancing the aridity.
Debates over how the tool making began are endless, but Africa started already to look a bit like now. With large parts becoming more and more arid vegetation changed, driven by climate. Areas covered by forests became savannas, fertile plains became desert, lakes shrunk, food became scarce...In the natural world, such changes can be balanced only by one factor-migration.
A view from a subsidiary canyon in the Great Valley acts as green corridor
(zoharafricansafaris.com)
As the eastern graben was cutting further through the African continent, it is possible that the rift valley offered some protection, a last refuge for primates in the area while the tropical forests retreated. In order to get to food and safe conditions, these beings had to move more and adapt to new environments and landscapes. New landscapes meant new food resources and required new ways of procuring it.
A seasonal migration turned into a permanent one that in the end, over the course of 3 million years, led to us...