And how they’ve made us human The evolution of tools And how they’ve made us human

Chimpanzee Tools Stones for cracking nuts Branches for termite fishing Spears to hunt bush babies Like we’ve talked about many times already in class, chimps use stripped branches to fish for termites.   Some chimps in the Savannah have also been spotted creating spears to stab bush babies sleeping in the hollows of trees. Chimps can learn how to make tools from humans, but they can’t, or at least don’t create more sophisticated tools like the ones I’ll be discussing in the wild.

Earliest tools 3.3 million years old Australopithecus Lomekwi 3 site, Kenya Australopithecus These tools were found just last year. Up until then, it was assumed that tool-making and meat-eating began with homo habilis. However, these tools suggest that it is likely that Australopithics created these tools and were eating meat.

Oldowan Tools 2.5 mya—Gona, Ethiopia Homo habilis Earliest consistent manufacture of stone tools Need based manufacture Homo habilis is thought to have first appeared around 2.4 million years ago, so it is possible that Australopithecus started producing them.   Basically when they needed a stone tool and they didn't have one, they made one right there and then most likely dropped it when they were finished with it.  Tools were fashioned this way for about a million years, with small improvements along the way.

Oldowan Tools Percussion Flaking Flake Tools Core Tools Cutting Hammering, chopping, and digging There were two types of tools made by a process called percussing flaking. This technique involves knapping, or striking a hard stone against quartz, obsidian, flint or any other rock whose flakes can hold an edge.  This technique requires a strong precision grip, which no modern primates, aside from humans, has. Percussion flaking creates two types of tools that were used in this period. The first is flake tools. When the rock is struck, it produces the “flakes” of rock which are thin and sharp edged. These are essentially knives. These are the tools that were likely used for butchering animals Second are the core tools, which you can think of as the leftovers or by-product from producing the flake tools. This is the bigger rock created by using this technique. It usually fit easily in the hand and was used for hammering, chopping and digging. Its also possible that tools were made from perishable items. Some paleoanthropologists think that wood and animal bones and horns may have been used as tools as well. However, there’s a lack of evidence for systematic shaping. It’s also unlikely that these hominids were aggressive hunters. They were probably mostly vegetarian and occasionally scavenged meat from leftover large predator kills.

Acheulean Tools 1.8—1.5 mya Homo erectus More sophisticated technology Brains-for-Guts Hypothesis Acheulean tools developed out of Oldowan technology between 1.8 and 1.5 million years ago. These tools emerged shortly after the emergence of Homo erectus (1.9 mya). Homo erectus had lost all of their adaptations for climbing trees and were a mostly terrestrial species. The Acheulean tools were much more sophisticated and most likely required much more cognitive ability than chimps and earlier hominids. They would make the tools and hold on to them. This technology seems to have been part of their adaptive niche and everyday lives.   This is also a place where you can see the brains-for-guts hypothesis. Homo erectus evolved with bigger brains and smaller guts to be able to better digest meat for protein to support that bigger brain. That being said, meat likely did not become the main food source for them because as seen by traditional societies and chimps, their diet is made up of mostly plants.

Acheulean Hand Axes Fairly standard shape Advanced percussion flaking Paleolithic Swiss Army knife The most important of the Acheulean tools was the hand ax. These tools have a pretty standard shape and size, usually teardrop shaped. It is still unclear whether these were hand axes in the way we think of them, like attached to a handle. These could have been handheld tools. These were created by percussion flaking, like the Oldowan tools. However, the patterns on some of the later tools suggest that some kind softer hammer, such as bone or antlers or hard wood, was used to get a finer, sharper edge. Paleoanthropologists believe that the hand ax was essentially a Swiss Army knife. They were used for chopping wood, digging, butchering animals, cracking nuts and bones, etc.

Zhoukoudian Late Homo erectus site 700,000—200,000 years ago Evidence of the change in subsistence patterns The Australopithic diet was believed to consist mostly of wild plants and occasionally meat or eggs that were scavenged. Homo erectus appears to have taken it a step further with small game hunting, while also scavenging for killed larger game. At Zhoukoudian, they found tens of thousands of remains from food including pigs, sheep, rhinoceros, buffalo, and deer. There were also bones from small animals like birds, turtles, rabbits, rodents, and fish. (and oyster and mussel shells). They were exploiting all the animals that they could for food from their environment. It is also probable that they were eating the wild plants as well. One of the first homo erectus remains were found at this site as well

Expanding to new environments Homo erectus was the first species to move from tropical and subtropical climates to temperate climates 500,000 years ago in Asia Earlier in Europe Technological advancements & new subsistence patterns The move to colder climates was made possible by the tools they were able to make, and the change in their diets. The cold weather probably wasn’t as much as an issue for them as it was for the plants that they would have normally lived off of. Meat from animals provided the energy they would have needed to survive.

Mousterian Tools 100,000 years ago Neanderthals Levallois core technique These mousterian tools were created using the Levallois core technique. Percussion flaking was used on one side to create a tortoise shell shape. Then a heavy blow is given to one end of the rock to produce the tortoise shell side and then the other side is flat. This levallois flake was used as a knife or scraper, or spear points

Fire First fire evidence For cooking and heating 790,000 years ago in Israel For cooking and heating 780,000—400,000 years ago in Zhoukoudian The first evidence of hominid-created fire was found in Israel 790,000 years ago. There has been evidence of fire earlier, but there is no concrete evidence that hominids were responsible. However the first evidence of fire being used for cooking is dated sometime between 780,000 and 400,000 years ago. We have no idea how homo erectus obtained fire or if they could make one at will. They are fairly certain, however, that by 100,000 years ago, neanderthals were able to create fires and use them regularly. Its not certain how they made them, but its assumed that they use flint to produce sparks.

Biocultural Evolution When natural selection is altered by cultural advancements Culture can create non-biological solutions to environmental challenges, which potentially reduces the need for genetic responses to evolve Normally when animals move into new environments or climates, they would evolve based on mutations and natural selection. For example, when homo erectus moved into cooler climates, nature should have selected for more fat, more hair, etc. Instead, they adapted by living in caves, becoming more equipped to eat meat, and eventually using fires. Their intelligence is what was selected for in future generations.

Knapping Experiment Stone tool making and brain function using PET scans Adequate force, correct position, and correct angle Heavy activation in cortical and subcortical regions Indicates knapping requires some degree of sophisticated cognitive function A study in 2000 examined the relationship between stone tool making and brain function. They monitored participants brain function using a PET scan while they were trying to create these stone tools. In order to create these tools, you need adequate force, and you need to hit the rock in the right place at the right angle. There was heavy activation in the cortical and subcortical regions—these regions are associated with somatosensory and motor processing and are linked to complex spatial cognition.

So, how have tools made us human? Biological evolution Helped exploit environmental resources Protect against predation Tools allowed us not to adapt to our environments, but to adapt environments to us Biologically, we lost sharp nails because of cutting tools. Brains-for-guts hypothesis. Increased manual dexterity and fine motor control. We also saw a reduction in jaw size and strength due these stone tools. This reduction in jaw size also may be attributed to the development of language because as the jaw got smaller, lips became more moveable. Actually, within the last 30,000 years, there has been a decrease in human brain size because our technology allows for us not to have to think so hard. We have computers and phones to remember stuff for us, etc. We don’t need as expensive of brains as we used to. Composite tools Argunacian tools Increased social aspect Increased cognitive ability We are tool dependent