Paper Example on Fossils of Hominids That Lived Before Modern Man

Introduction

For millions of years, since the earliest ancestors of humans inhabited planet earth, various hominids have lived on earth. The discovery of fossils has brought humans closer to realizing our divergence from apes that has occurred over the ages. Dating technologies have been pivotal at tracking the evolution ages and structuring of the human lineage from apes. As time progressed, hominids developed improved features for their adaptation to the environment to cater for their needs, a change that resulted in the evolution from ape-like creatures to modern man. Below is a discussion of some of the fossils of hominids that lived before modern man, the ages they lived and the distinguishing morphological characteristics.

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Cranium A

Genus and species: Sinanthropus pekinensis

Time range: 0.23 to 0.7 m.y.a

Location: Zhoukoudian, near present-day Beijing

The species was characterized by the large cranial capacity of about 1000 cubic centimeters, though some approached 1300 cubic centimeters (Song). Its cranial capacity increases with advancement in the hominid lineage, with the species, thought to precede Homo sapiens species. The species depicted a flat cranium in profile with a relatively small temple. Additionally, it possessed a keel on the crown of the skull where powerful jaw muscles were attached as in the following hominid species like the Homo sapiens. It also possessed very thick skull bones, a broad palate, an occipital torus and heavy brow ridges (Song). One of the distinguishing traits of the species was the chinless jaw. The species possessed modern teeth with relatively large canines and molars. It also had often wrinkled enamel for the molars. Its limbs resemble that of modern man. It is even thought to have been able to handle fire as its fossils were discovered alongside burnt animal bones. It is believed to have been hunting large mammals for food and was associated with tools and a cultural aspect that included burying their dead (Song). The species is placed between Homo erectus and Homo neanderthalensis.

Cranium B

Genus and species:

Time range: 0.12 to 0.8 m.y.a

Location: Western Europe

The species was characterized by massive, projecting brow ridges, also known as a supraorbital torus(Buck). It possesses a low frontal bone, which represents a forehead that does not extend massively above the level of brow ridges. It also had a sagittal keeling along the top of the skull from front to back, where chewing muscles were attached. The trait depicted the species to feed on hard-to-chew foods. The species also exhibited separate supraorbital tori, brow ridges over each orbit, unlike in Homo erectus species. The species followed the Homo erectus species, making the lineage of the hominid exhibit increased supraorbital tori with advancement in the descent (Buck). Additionally, the species possessed postcranial vaults and parietal bones that were wide compared to the cranial base. It also possessed a large cranial capacity than its predecessors like the Homo erectus (Buck). The trait depicts that the cranial capacity in the hominid lineage increased with advancement in the lineage.

Cranium C

Genus and species: Ardipithecus ramidus

Time range: 4.2 to 4.5 m.y.a

Location: East Africa, rift valley

The species is characterized by a relatively smaller skull than later hominids in its lineage. Its cranial capacity ranges from 300 to 350 cubic centimeters (Simpson). In its descent, the cranial capacity increases with advancement in the hominid species. It exhibits substantial prognathism of the face. The posterior portion of the base of its cranium is shorter than that of chimpanzees as exhibited by other hominids in its lineage but is more significant than preceding hominids. Its dentition is well represented with associated upper and lower teeth, and it possesses thick dental enamel with relatively reduced canines, which lack honing complex (Simpson). The species also retains a diastema between the incisors and the canines. It was believed to travel from place to place.

Cranium D

Genus and species: Australopithecus anamensis

Time range: 3.9 to 4.2 m.y.a

Location: East Africa, Lake Turkana, Kenya

The species had well-represented jaws, and teeth characterize the species. It has large, broad premolars having relatively thick tooth enamel. Its teeth in front of the jaws are more extensive than in later Australopithecus species (Plavcan). Its lower third premolars are large and single cusped unlike in later species of its lineage. The following species possessed smaller and double cusped premolars. The species' upper canines are symmetrical when viewed from the side, showing that it preceded later species of Australopithecus, whose canines are asymmetrical. The species has deciduous molars resembling permanent molars. The trait depicts precedence of the species to later Australopithecus species, whose deciduous molars did not resemble permanent molars. The species also possesses small canines. The dental arcade of the species, having premolars and molars located right after the canines, makes it normally U-shaped when observed from above (Plavcan). The species possesses a relatively smaller bony ear opening compared to later species. The species follows Ardipithecus ramidus species in its evolution lineage.

Cranium E

Genus and species: Homo neanderthalensis

Time range: 0.03 to 0.15 m.y.a

Location: France, Europe

The species possessed a low and long skull with significant brow ridges, which formed individual curves above the orbits of each eye unlike their predecessors, Homo erectus. Its skull resembled that of Homo heidelbergensis, an earlier species in its lineage, though slightly more significant. Its cranial capacity averaged 1400 cubic centimeters (Curley). Its face had the middle and lower parts positioned relatively forward to the braincase, a condition that was referred to as midfacial prognathism. It had relatively larger nasal aperture compared to Homo sapiens. Its skull was oval-shaped since it had the widest part of the skull at the middle of the braincase. Its braincase exhibited occipital buns and Suprainiac fossae, traits not presented in preceding Homo erectus species or the following Homo sapiens species(Curley). It possessed large mandibles with molars having large pulp chambers. Its postcranial skeleton was built in thick bones. It was thought to hunt large, dangerous prey.

Cranium F

Genus and species: Australopithecus africanus

Time range: 2 to 3 m.y.a

Location: Tuang, Southern Africa

The species lacked sagittal crest, a crest along the skull's midline where chewing muscles were attached. The species possesses a relatively larger cranial capacity than Australopithecus afarensis, which precedes it in the hominid lineage. It has larger postcanine teeth and small anterior teeth, which depicts that the species depended on foods that were not hard to chew (Skinner). It has a slightly less prognathic face. It possesses a flexed cranial base that is more angulated in the middle. Additionally, it possesses nasal pillars which are supportive bones on both sides of the nasal opening of the cranium. The species has a taller anterior bone making up the forehead, and an occipital bone that makes up the back of the cranium. It has round-shaped skull due to the long and flat orientation on the base and a high points in the change of direction at the top(Skinner).

Conclusion

In conclusion, following the dating ages of the cranial fossils, the chronological order for the crania would be that cranium C that represents Ardipithecus ramidus is the oldest, followed by cranium D that represents Australopithecus anamensis, and cranium F that represents Australopithecus africanus. The order would then follow with cranium B that represents Homo heidelbergensis, followed by cranium A that represents Sinanthropus pekinensis, and finally, cranium E that represents Homo neanderthalensis.

Work Cited

Buck, Laura T., and Chris B. Stringer. "Homo heidelbergensis." Scientific report. 2014.

Curley, Angelina, and Shara Bailey. "A comparison of metric variation in deciduous molars of Homo sapiens and Homo neanderthalensis." AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY (2018): 165.

Plavcan, J. Michael, Carol V. Ward, and Fredrick K. Manthi. "New specimens of Australopithecus anamensis from Kanapoi, Kenya." AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY (2015): 156.

Simpson, Scott W., et al. "Postcranial fossils of Ardipithecus ramidus from Gona, Ethiopia." AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY (2018): 165.

Skinner, Matthew M., et al. "Human-like hand use in Australopithecus africanus." Science. 2015.

Song, Xing, Maria Martinon-Torres, and Jose Maria Bermudez de Castro. "The fossil teeth of the Peking Man." Scientific Reports. 2018.