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Jeoloji Mühendisi

Human Evolution from a different sight


Humankind came along a very long way from single cell to the homo sapiens and in this regard, there’re multiple effects that are directly affected way of human evolution. The purpose of that work is the summing of the different influences that are coming from different origins and giving extended information about the presentation. In addition, the paperwork contains some fictional elements based on scientific sources in order to express behavior of evolution and make ensure being much more comprehensible.

2.Effectiveness of dinosaurs

We have limited resources on this subject, only I would like to express my opinion on this issue. It is undeniable that the disappearance of dinosaurs accelerated mammalian evolution. Furthermore, there is no serious evidence though, negative effects of dinosaurs on mammal evolution such as shrinkage body could directly triggered our survival from influences of impaction and provided us protection during the impact winter. Likewise, the tender senses of mammals that they have developed in order to withstand predatory hazard may assist us to achieve success through next steps of our evolution.

3.Influences of Chicxulub impactor (65 ma)

Of course, the disappearance of the dinosaurs was a surprise to mammals and the evolutional velocity is tripled after Cretaceous–Palaeogene mass extinction (Hallidey et al., 2016). The impaction (Fig.1.) directly caused impact winter and consequence of changes on paleoclimate during the early paleogene, triggered elimination of primary producers. Wherefore, herbivores could not survived from lack of food and that situation immediately gave rise to the extinction of predators (Covey et al., 1994). In that case, rising of the mammals was inevitable in consequence of reduction of the major threats (Meredith et al., 2011).

4.Roles of East African Rift and paleoclimate  (22-25 ma – Today)

The climate has always been the cornerstone of evolution, and its place in the human evolution is indisputable. The departure of the East African Rift (Fig.2.) has affected not only the ancestors of man, but all the life forms in the region. The seperating has changed the air currents comes from the Indian ocean that contains moisture and caused precipitation in the southern part of the Africa (Sommerfeld et al., 2014). In consequence of changing in air flow, the life forms confronted lack of precipitation and than, the natural selection has come into play. In that case, dryness shifted the vegatition from woods to the grasslands and savannah in a long period and that may express why ancestors of mankind left the trees (deMenocal, 2011). The fossil evidences show shifting of the biomes from south to north in Africa and the paleoclimate may express why. (Sommerfeld et al., 2014)

5.Human timeline

Essentially, there are countless of species to mention but only important ones going to be described. Figure 3. shows the timeline of homo sapiens in general terms.

5.1.Ardipithecus ramidus  (Late Miocene – Early Pliocene)

A.ramidus (Fig.4.) is a species of Hominin categorized Australopithecine of the Ardipithecus genus that has a small brain between chimpanzee and australopithecines with %20 size of the modern Homo Sapiens. The noticeable evolutional difference between chimp and A.ramidus is the shape of feet that is more suitable to walk. Moreover, composition of its teeth shows that A.ramidus was probably omnivore. They’re accepted as first human ancestors that are tried to leave trees and walk. Another significant characteristics of A.Ramidus are semi-upright posture and long arms which indicate evolutional steps of leaving trees (Gibbons, 2009).

5.2. Australopithecus afarensis (3.9 – 2.9 ma)

Aferensis (Fig.5.) is much more close to the Homo genus that is probably straight ancestor and, its canines and molars were much more smaller than early ancestors. In that case, its diet was more different than olders. It was probably an effective bipedal walker over short kilometers but still not efficient like modern humans.  Last but not least, there is no evidence of stone tools that were used by A. afarensis but some scientists suggest that they were using simple stone tools to carve animals (Conroy et al., 2000).

5.3. Homo habilis (2.1 – 1.5 ma)

That’s the first member of Homo genus that is also called handy man and has had a larger brain and used different kinds of stone tools. In appearance, H.Habilis (Fig.6.) had short and irregular arms compared with homo sapiens and its brain was half of the modern humans as capaticity. Furthermore, they were probaby living in groups and hunting (Montagu, 1965).

5.4 Homo Erectus (1.9 – 0.07 ma)

That’s also called upright man that is most famous species of hominids because of using fire under controlled. Likewise, H.Erectus (Fig.7.) used fire in order to cook their meal and that event totally changed the way of human evolution. Additionaly, the using of fire provided us protection and that was the start of human civilization (Wrangham et al., 2010). Also, they were substantially sociel just like modern humans and probably lived in clans. Last but not least, its chin muscles were getting weaker and brain was getting bigger because of chewing cooked meat cost low energy. H. Erectus was almost hairless and that provided perspiration to decrease body warming during the running. Over and above, it has had low shoulders and long body that allowed ability to run through long kilometers (Anton, 2003).


The evolution always works and happens all the time. As the environmental conditions continue to
change, natural selection will go into effect and will continue until the organisms undergo the most
harmonious mutation. As a result of this work, we can suggest that the effects of geology on
evolution cannot be denied. If only an event, a predator or a mutation had changed, we might not
have a story to tell right now.



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Conroy, G.C., Falk, D., Guyer, J., Weber, G.W., Seidler, H., Recheis, W. (2000),  Endocranial capacity in Sts 71 (Australopithecus africanus) by three‐dimensional computed tomography, The Anatomical Record, 258(4):391-396

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Halliday, T.J.D., Upchurch, P., Goswami, A. (2016), Eutherians experienced elevated evolutionary rates in the immediate aftermath of the Cretaceous–Palaeogene mass extinction., Royal Society B., DOI: 10.1098/rspb.2015.3026.

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Meredith, R.W. Et al. (2011), Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification, Science, 334:521

Mess, A., Carter, A.M. (2007),  Evolution of the placenta during the early radiation of placental mammals, Comparative Biochemistry and Physiology, 148.4: 769-779

Montagu, A. (1965), Homo Habilis, Science, 49.3687: 918-918

Pinkerton, J.H.M. (1973), Some aspects of the evolution and comparative anatomy of the human pelvis, BJOG: An International Journal of Obstetrics & Gynaecology, 80.2: 97-102

Radhakrishna, S. (2006), From Purgatorius ceratops to Homo sapiens, Resonance, 11.8: 69-80

Sommerfeld, A., Prömmel, K., Cubasch, U. (2014), The East African Rift System and the impact of orographic changes on regional climate and the resulting aridification, International Journal of Earth Sciences, 2014:1-16

Wrangham, R., Carmody, R. (2010), Human adaptation to the control of fire, Evolutionary Anthropology: Issues, News, and Reviews, 19.5: 187-199


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