Biological trends in human evolution and cultural evolution

Many of the cultural changes seen in human societies are based on biological and technological evolution. If we look at human pre-history, we can also see an example of a profound cultural change that was based on technological evolution and biological evolution.
This cultural change in early human species was tool making and it first appeared in the habilines.( Homo habilis)
Initialy tool making developed through a technology that used stone tools to create new tools that were also made of stone.Fore example, using a hammer stone to make stone flakes to be used as cutting tools.
The significance of this cultural change is in the fact that tools.Such as axes, enable the power of the body to be concentrated on a small area of an object so that it can be cut or otherwise manipulated and tools. Such as levers , provide a mechanical advantage.
The development of a tool-making culture by early human species depended on both technological evolution and biological evolution.

Tool making was possible only because much earlier, biological evolution in hominins had resulted in two important developments.

1. Dipedal (two-footed) locomotion that freed the hands fore other purposes.
2. Increased brain size (encephalization) that gave the capacity for greater problem solving skills.

So biological evolution provide the physical and cognitive frame work in which cultural change based on technology could take place in human species.

HUMAN SOCIETY  AND CULTURE

Human have two hereditary systems,

• A genetic system, which transfer biological information from biological parent to offspring through the coding properties of DNA.
• A cultural system , which transfers cultural information, ideas from speaker to listener, from writer to reader, from performer to spectator through social interaction coded in language and custom and embodied in records and traditions.

Hominoids evolved during the Miocene in Africa during the early stages and then spread to Europe and Asia during the later miocene , undergoing adaptive radiation.

CULTURAL EVOLUTION

Cultural evolution in humans can be defined as transfers the cultural information, ideas such as tools, books, writing, art, language, music, ritual, beliefs etc. From generation to generation with relevant changes.

CULTURAL EVOLUTION TRENDS

• Sahelanthropus tchadensis
• -Live in wooded areas.
• -Most of cultural evolution is pure speculation.

• Australopithecus group
• -Only debatable evidence that they made tools and no evidence that they had home bases or shared food.
• -Probably opportunist feeders.
• -First humans evolved from anstralopithecine  ancestors about 2 mya in africa.

• Paranthropus genus 
• -Some evidence they used bones or perhaps sticks to dig up roots.
• -Evidence suggests robustus ate course, tough food supplemented by small insects.

• Homo genus
• -At that time cultural evolution coupled with the brains evolutionary development is the increasingly complex behavior exhibited by hominius.
• -At that time biological evolution caused major changes of cultural evolution.

So without understanding our anatomy we cannot understand our culture.More important is the brain size compared to body size(5-10 fold increase of brain size relative to body size).Cranial capacity has increased gradually from Australopithicines to Homosapienss. Another important factor is the way of brain is organized.

Two area of the brain have become highly developed in modern humans.

Increased brain size was helpful for the hominin evolution.

• Increase of interligence
• Increase of behavioral flexibility
• Increase of manual dexterity
• Increase of social complexity
• Language developement

The language function all occur on the left hemisphere of the brain in most humans.

• Broca's Area:-
• Functions to process the generating of speech .
• Located at the base of the motor cortex, which handles the tongue, vocalization, and lip movements. 

• Wernick's area-
•   Functions to process the reception of speech.
•   Located at the temporal lobe, which process hearing.

The angular gyrus is the part that coodinates all the sensory functions.Its function for language is to translate all the sensory information in to the sense of hearing.So we can assign meaning to speech.

Language makes long-term cumulative cultural evolution possible.

Language can be defined as:-

               Symbols that convey meaning, plus rules for combining those symbols to that they can be combined to generate infinire variety of massages.

Uses of language:-

     

                  -To coordinate activities.(eg: hunting)

                  -We can communicate knowledge about relevant aspects of the environment.

                  -To develop technologies.

                  - Identify things with names and descriptions.

                  -To express our emotions.

                  -Remember and utilize the past as well as plan for future.

Due to this, communication via singing and chanting was developed. And also better hearing and listening skills were occured as a result of speech.Art also used as a communication medium.

                    Drawing of pictures and symbols on cave walls, bone carvings, clay statues were observed .

To be a hominid, fossil must have an anatomy suitable for standing erect and walking on two feet.


 Human anatomy differs from that of an ape largely because humans are bipedel while apes are quadrupedal.Bipedalism led to the better locomotion and freeing of hands.During the transition from Austraopithicians to Homo sapiens,

• Location of foramen magnun became more foreward,

• The shortening and narrowing if pelvis, 

                       

•  Evolution of femur into a slightly more angular position to make the center of gravity towards the geometric center of the body,
• The knee and the ankle joint became increasingly robust,
• Vertibral column became s-shaped,  

• Shortening of arms relative to the body size,
• Reduction of the sloping of forehead  

were observed.Thease helped in efficient locomotion,easy running, and to maintain erect posture.

Some trends in general morphology of the skull are:

Dental  arcade- became more arch like/parabolic.

Tooth size of hominoids decreased from Astralopithecines to Homo sapien and there was a marked decrease of tooth size within Homo sapiens.

Crests and ridges-

                           Both the great apes and early hominids have obvious crests and ridges on their skulls.Muscles attached to these crests and ridges are vary useful for chewing hard plant matter.With the evolution and diatery changes sadittal and nauchal crests and brow ridges reduced gradually.In modern humans they are highly reduced and nauchal creast is absent in most ,due to evolution of upright posture.

There is a general trend towards a flatter facial angle with the appearance of more recent hominids culminating in the vertical face of Homo sapiens.

Degree of sexual dimorphism also reduced with the evolution of humans ,due to the reduction of male canine tooth and due to the reduction of brow ridges.But the human retain a degree of sexual dimorphism in the distribution of body hair and subcutaneous fat and in the overall size.

The barrel shaped ribcage and the presence of waist in Homo erectus suggest that significant quantities of meat were being eaten.
An increase in amount of meat in the diet, with the greater fat content and higher calories,would also fuel the higher energy demand of a larger brain.

Advantages of Bipedalism and associated skeletal changes

• Allowed fast running which is necessary for active hunting on the open savannah
• Allowed tool making and use
• Played a major role in care and provisioning of offsprings,tracking migrating herds and predator avoidance.

Better tool making improved food supply and therefore longer period of parental care.

We have much longer and opposable thumb which  results in more precise and powerful grip.

Homo habilis:

Was known as the handy man made Oldowan tools.
                     

First appeared 2.5 Mya.

They were successful hunters,made shelters and lived in bands of about 12 people.

Homo erectus:

Used Acheulian tools and was known as the fire maker.

Built shelter supported by wooden pools.

Serious cooperative hunters.

Homo Neanderthalis:

Used Mousterian tools and began to attach stone tools to handles.

Lived in caves

They were so intelligent and built stone walls,dressed in hides, buried their dead and had strong social bonds.

                                                                                                                                                                                                            


Homo sapiens:

Used advanced tools of flint and bone.
Used blades and points.
Called upper Palaeolithic tools
.                                      
Skilled hunters lived in large groups.
Engraved and painted on walls,carved statues etc.

Farming began 10,000 years ago in middle east.This period was known as New stone age.
By about 7000 years ago, agriculture became established.
            -learning to cultivate a food-producing plant;not just gathering a naturally occurring plant.
            -domestication of animals.(Dogs,sheeps,goats,pigs,cattles)
As the population became larger there was a shortage of food and climate was changed.

The Experimental Study of Human Cultural Evolution

During the early evolutionary period biological evolution was occurred more frequently than the cultural evolution.But when it comes to Homo sapiens, cultural evolution dominated biological evolutionary trends significantly.