Evidence, fossils and bones
Early human fossils and archeological remains offer the most important clues about our ancient past. These remains can include bones (fossils), tools, footprints, cave paintings and butchery marks on animal bones.
Many significant findings have been found throughout history. Fossils are fascinating reminders of life in ancient times. They can also reveal an amazing amount of information. Fossils have, for example, helped us work out who some of our direct ancestors might be. They have also helped us gain insights into the changing environments and lifestyles of these early people.
Fossils are the preserved remains of ancient organisms. Animal fossils include actual parts of the body such as bones or an entire skeleton or traces left by the body such as a trail of footprints.
Early human fossils and archeological remains offer the most important clues about our ancient past. These remains can include bones (fossils), tools, footprints, cave paintings and butchery marks on animal bones.
Many significant findings have been found throughout history. Fossils are fascinating reminders of life in ancient times. They can also reveal an amazing amount of information. Fossils have, for example, helped us work out who some of our direct ancestors might be. They have also helped us gain insights into the changing environments and lifestyles of these early people.
Fossils are the preserved remains of ancient organisms. Animal fossils include actual parts of the body such as bones or an entire skeleton or traces left by the body such as a trail of footprints.
More than 2000 ancient individuals are now found in our ancestral fossil record. Some of these individuals are represented by reasonably complete fossil skeletons. However, this is relatively rare, particularly for our older ancestors who lived millions of years ago. Generally those that lived more recent that those of ancient years, leave more complete fossil skeletons.
Jaws and teeth are the most commonly found fossils. This is because they are especially hard parts of the skeleton and therefore have a better chance of of lasting long enough to become fossilised. The teeth can suggest to us the diet, lifestyle and relationships of their owners. They can also help indicate the owners age at the time of their death. |
Skulls can provide details about the size and shape of the brain, face and teeth. The base of the skull can also provide information on posture as it shows how the head was supported on the body and how the organism stood. This is called the forenan magnum. Determining the way the spine stood The skull can also determine the details of the face. For example the sagittal crest ( ridge that holds jaw muscles), brow ridge (bones where eye brows would be) and the hollowness of their cranial capacity.
Most of our ancestors’ fossils are found in sites that were once on the margins of ancient lakes and rivers, inside caves or were subject to volcanic eruptions. In some sites, the conditions needed for fossilisation occurred over relatively short time spans. In others, a rich fossil record accumulated over millions of years.
Most of our ancestors’ fossils are found in sites that were once on the margins of ancient lakes and rivers, inside caves or were subject to volcanic eruptions. In some sites, the conditions needed for fossilisation occurred over relatively short time spans. In others, a rich fossil record accumulated over millions of years.
One of the most famous finds in history, was the discovery of 'Lucy'.
In 1974, a group of scientists located their field trip in the Afar triangle, a remote area in Ethiopia. The expeditions leader Donald Johanson discovered in an ancient lake bed, parts of an elbow joint, then part of a skull, a femur, several vertebrae, parts of a pelvis, some ribs and other bones and bone fragments. Eventually Johanson's team discovered several hundred pieces of bone that formed about 40% of an entire skeleton. The skeleton was that of an ape- like creature who walked erect, alittle more than over a metre tall, and lived in this part of Africa about 3 million years ago. Because part of the pelvis was present, it was possible to identify the bones as being female. The condition of her teeth suggested she was 25- 30 years old when she died. The fossil skeleton was given the name 'Lucy'. Lucy was not a human but a hominin. She was classified as a member of the species Australopithecus afarensis. |
Comparisons of the skull
Cranial Capacity: Hominins have a larger cranial capacity (apes have a cranial capacity of approx 400cm3 compared with1400cm3 in humans). This is an indication of their brain size. Prognathism: Apes have a pronounced muzzle, the teeth protrude out from their face. This is called a prognathism. This is common in early Hominins also, but later Hominins have a much flatter face. |
Foramen Magnum
This is the hole at the base of the skull where the spinal cord enters the brain. The foramen magnum is towards the back of the skull in apes, whose posture was not fully upright. In humans, the foramen magnum is at the fulcrum(balance point). The bones of the skull that balance on the vertebra / spine, called occipital condyles show the same trend (at the rear of the skull in apes, central in humans) |
Nuchal Area
This is the area where the neck muscles attach onto the back of the skull, to keep it balanced on the spinal column / looking forward. Apes have very large nuchal areas and associated neck muscles because greater muscle strength is required keep the skull looking forward when the spine is attached further to the rear of the skull. |
Temporal muscles
These are the muscles that pull up the jaw (bite). The temporal area is where these muscles attach onto the skull. In apes these are both much larger. This probably corresponded to a much more primitive diet that included a lot more fibrous plant material that needed to be ground down. |
Zygomatic Arch
These are a bony arch just behind the cheeks. They provide a gap for the temporal muscles to pass through (see above). They are much larger in apes to accommodate much larger temporal muscles.
These are a bony arch just behind the cheeks. They provide a gap for the temporal muscles to pass through (see above). They are much larger in apes to accommodate much larger temporal muscles.
Brow Ridge
This is a bony ridge located above the eye sockets. Its purpose is to reinforce the weaker bones of the face (reduces vertical stress). In Apes they are much larger due to the tremendous strain put on the cranium by their temporal (jaw) muscles. Without this reinforcement the eye sockets would collapse. The brow ridge was one of the last traits to be lost in the path to modern humans |
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Sagittal Crest
The Sagittal Crest is a ridge of bone running lengthwise along the midline of the top of the skull. The presence of this ridge of bone indicates that there are exceptionally strong jaw muscles. The sagittal crest serves primarily for attachment of the temporalis muscle, which is one of the main chewing muscles. It is absent or greatly reduced in most Hominins (with the notable exception of the Paranthropus genus). |