most anthropologists surmise that members of early Homo species, rather than the australopithecines, made those tools. After all, early Homo had a brain capacity almost one-third larger than that of the australopithecines. But the fact is that none of the earliest stone tools is clearly associated with early Homo, so it is impossible as yet to know who made them.
As the figure (on the left) suggests, we can map the tools usage alongside of the different species of early homo around 2 to 1 Million Years. This clearly reflects the fact that there were existence of cultural aparatus for adaptation to the environmental challenges.
As we can map between the early homo along with the stone tool assemblages, we can have roughly the following picture.
Therefore, as we can see a combination of the biological, especially the fossil evidences along with the artifact are all we have to imagine what might have been the past human’s lifeways. Although, it is difficult to pin-point how, early humans have adapted to their environment and came out of the challenges, archaeologists and palaeontologists have nevertheless gave us certain clues. Archaeologists have speculated about the lifestyles of early hominins from Olduvai and other sites. Some of these speculations come from analysis of what can be done with the tools, microscopic analysis of wear on the tools, and examination of the marks the tools make on bones; other speculations are based on what is found with the tools.
Archaeologists have experimented with what can be done with Oldowan tools. The flakes appear to be very versatile; they can be used for slitting the hides of animals, dismembering animals, and whittling wood into sharp-pointed sticks (wooden spears or digging sticks). The larger stone tools (choppers and scrapers) can be used to hack off branches or cut and chop tough animal joints.6 Those who have made and tried to use stone tools for various purposes are so impressed by the sharpness and versatility of flakes that they wonder whether most of the core tools were really used as tools. The cores could mainly be what remained after wanted flakes were struck off. Archaeologists surmise that many early tools were also made of wood and bone, but these do not survive in the archaeological record. Present-day populations use sharppointed digging sticks for extracting roots and tubers from the ground; stone flakes are very effective for sharpening wood to a very fine point. None of the early flaked stone tools can plausibly be thought of as weapons. So, if the toolmaking hominins were hunting or defending themselves with weapons, they had to have used wooden spears, clubs, or unmodified stones as missiles. Later, Oldowan tool assemblages also include stones that were flaked and battered into a rounded shape. The unmodified stones and the shaped stones might have been lethal projectiles.
There are many prominent approaches to the understanding of the evolution of human behavior:
Sociobiology: an approach that uses principles drawn from the biological sciences to explain human social behavior and social institutions.
Human behavioral ecology (HBE): a perspective that focuses on how ecological and social factors affect behavior through natural selection.
Evolutionary psychology (EP): a perspective focused on understanding the evolution of psychological mechanisms resulting in human behavior.
Dual-inheritance theory (DIT): the perspective that culture is evolutionarily important, that culture evolves in a Darwinian fashion, and that understanding gene–culture co-evolution is the key to understanding human behavior.
Contemporary evolutionary theory has developed new understandings of the complex relationships between organisms and biological patterns not fully encompassed by the four genetic evolutionary mechanisms of mutation, natural selection, genetic drift, and gene flow. Within the framework of the extended evolutionary synthesis, there is recognition of how extra-genetic inheritances, developmental biases, and niche construction also contribute to evolutionary processes, all of which provide the foundations for recognizing the biocultural patterns that affect human evolution. The approach presented here is known as a constructivist approach, which emphasizes that a core dynamic of human biology and culture is processes of construction: the construction of meanings, social relationships, ecological niches, and developing bodies.
Jablonka and Lamb point out that explanations of human evolution have traditionally focused on only one system of inheritance—the genetic system—which relies on explanations at the level of genes. But human evolution also works in the epigenetic, behavioral, and symbolic inheritance systems. One such system is the epigenetic system of inheritance: the biological aspects of bodies that work in combination with the genes and their protein products, such as the machinery of the cells, the chemical interactions between cells, and reactions between types of tissue and organs in the body. The epigenetic system helps the information in the genes actually get expressed, and therefore it impacts genes as well as the whole body by altering an individual’s physical traits. Offspring may inherit those altered traits due to the past experiences of their parents. In humans, epigenetic inheritance is more difficult to observe because of our long life spans, genetic diversity, and the fact that we don’t live in highly controlled environments. Epigenetic inheritance may be taking place, however, in historical variations in access to food, which can result in health effects on offspring.
Another such system is the behavioral system of inheritance: the types of patterned behaviors that parents and adults pass on to young members of their group by way of learning and imitation. Consider birds, for example. They must learn from their parents which foods to eat and which to avoid, since there are no genes telling them what to eat. In humans, we call these learned and patterned behaviors norms, customs, and traditions. Cross-cultural variability of human norms, customs, and traditions demonstrates the behavioral flexibility and plasticity of humans, something that has long shaped the adaptive possibilities of our species. We learn a wide variety of behaviors from authority figures and peers simply by observing and being corrected in everyday life. We also construct elaborate and formalized social institutions to mediate, manage, and control the behaviors of group members. These activities consume much of our energy, thought, worries, and creativity, but none of this activity is located in any specific genetic sequences. As a result, in humans there is also a symbolic system of inheritance: the linguistic system through which humans store and communicate their knowledge and conventional understandings using symbols. This system of inheritance is intimately tied to the behavioral system of inheritance. Symbols are rooted in our linguistic abilities. With some exceptions, all humans are capable of learning a language. This is enabled by a certain genetic make-up that only other humans share. The actual language we do learn from our parents and peers then helps shape the way we perceive and interact with the world around us. Symbols and the meanings people attribute to them are arbitrary and socially constructed and are not coded in the genes. Another foundation of the biocultural perspective is the shift in thinking about evolution that came with the introduction of developmental systems theory (DST): an approach that combines multiple dimensions and interactants toward understanding the development of organisms and systems and their evolutionary impact. DST focuses on the development of biological and behavioral systems over time rather than on genes as the core of evolutionary processes and rejects the idea that there is a gene “for” anything. Evolutionary processes are fundamentally open-ended and complex because they involve the ongoing assembly of new biological structures interacting with non-biological structures. In this sense development comes from the growth and interaction of several distinct systems: genes and cells, muscles and bone, and the brain and nervous system. All develop over the lifetime of the individual. Thus, evolution is not a matter of the environment shaping fundamentally passive organisms or populations, as suggested by natural selection theory, but consists of many other developmental systems simultaneously changing over time.
Human evolution is thus characterized by a complex set of interactions among the various biological systems occurring throughout an individual’s lifetime, all interacting with factors like human demography, social interactions, cultural variations, language, and environmental change. These processes make it more difficult to describe our evolution but do recognize the actual complexity involved in how human biocultural systems work. A critical aspect of our biocultural existence involves changing and constructing the world around us. A niche is the relationship between an organism and its ecology, which affects how that organism makes a living within a particular environment and leads to the construction of niches. The scale of niche construction and niche destruction can occur at the narrow local level or on a global scale and can change the kinds of natural selection pressures placed on the organisms involved. Many different types of organisms engage in niche construction.
Much of what we take as “natural” in a landscape is actually an artifact of human niche construction and its effects. That human influence over ecosystems is the defining dynamic of our world today leads a number of scholars to adopt the term Anthropocene: the geological epoch defined by substantial human influence over ecosystems. Human reorganization of ecosystems creates conditions for a co-evolutionary process in which humans, plants, animals, and microorganisms can mutually shape each other’s evolutionary prospects. Thus, niche construction creates a kind of “ecological system of inheritance.” These approaches go well beyond privileging genetic mechanisms as the main or sole force in evolution. They do fit well with the ways in which some researchers have long seen selection interacting with environments over the course of evolutionary time without reducing those processes to natural selection. See “Classic Contributions: Sewall Wright, Evolution, and Adaptive Landscapes.”
It would be unreasonable to assume that all of the details previously discussed are accepted in equal measure. But in terms of meeting the challenge of constructing a holistic biocultural perspective, which takes culture and biology equally seriously, these positions provide the basis for a productively complicated understanding of human evolution. The constructivist approach acknowledges that biocultural dynamics are open-ended and involve interactions between diverse forces and agents.
We can imagine (if not reconstruct) certain cultural aspects as shaping much of what we are through foods we eat people we chose to mate. For example, Food taboos are generally part of being human, which involves imposing arbitrary symbolic divisions upon the natural world, and feeling somewhat arbitrarily that certain things are food and certain things are not food, in spite of the fact that both classes of things may be completely edible. The taboos are learned, not instinctual, because they change with the times, while still evoking diverse forms of repulsion or aversion. Not eating other humans is simply the food taboo that is most fundamental and universal. Most food taboos are more provincial: some peoples eat pig meat, others don’t; some peoples eat dog meat, others don’t; some peoples eat insects, or poisonous pufferfish, or Twinkies, or whatever weird things happen to be in their environment and might be nutritious, tasty, or fun to eat. This is not a biological universe, contrasting things that are healthy and filling and digestible against things that aren’t; but a symbolic universe, contrasting things that are considered proper and acceptable to be eaten against things that aren’t.
Symbolic boundaries are fundamental to human thought, but of course they are imaginary. Those boundaries are crucial to group identity, and they may be cast in terms of what is considered appropriate self-adornment, or how to communicate properly – that is to say, the “boundary work” of culture. In this case, however, the symbolic boundary lies not between those who wear saris and those who wear blue jeans, or between those who distinguish between the “S” sound and the “Sh” sound and those who don’t9 – but between those who count as human and those who don’t. The rule is: Animals eat people, people don’t.
Not only are there certain foods that you cannot eat, even though they are edible, but there are also certain people that you cannot marry or have sex with, because of incest taboo even though they may be really attractive and may love you. The people who are covered by the taboo may vary somewhat from place to place. As noted above, your first cousin may be either a preferred partner or a taboo partner. Your first cousin may even be both – your mother’s brother’s offspring and your mother’s sister’s offspring may be considered to be different relations, one a fine mate and the other incestuous. Non-blood relations may be covered by the same taboos as blood relations, such as your in-laws. The Bible’s incest prohibitions specifically cover a man’s stepmother, aunt (i.e., uncle’s wife), and daughter-in-law, even though they aren’t blood relations. There are several biological consequences of this form of incest, first, this opens up an avenue for genetic diversification and prevents inbreeding, second, because one has to find mate outside of his/her close group, one has to wait for a while which helps getting human the time needed for become physically and mentally mature, third, this stops indiscriminate sex and gives avenues for human mothers to rear their children before they pregnant again.
Emergence of the non-sexual bond between opposite-sex siblings, which is special to humans, for it creates a new kind of social relationship: a lifelong intimate interaction between opposite-sex individuals that is not sexual. This will be symbolically extendable in three ways: first, to other family members, and banning sexual relations with them, once there is a concept of the family; second, to other opposite-sex community or clan members, accompanying a broader conception of kinship than just the family, and forming the basis of exogamous marriage rules;23 and third, to other generations, where the offspring of those same taboo opposite-sex siblings will be cross-cousins, and may be symbolically special, but in the directly opposite way, as normative spouses.