Origin and Evolution of Man: Definition and Examples

Evolution is the process of gradual change in the characteristics of species over generations, leading to biodiversity. It is driven by mechanisms like natural selection, genetic drift, mutations, and gene flow. Evolution explains the origin and adaptation of organisms to their environment. In this article, evolution, theories of human evolution, fossil evidence of human evolution, and anatomical changes in human evolution are discussed. The Origin and Evolution of Man is a topic of the chapter Evolution in Biology.

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This Story also Contains

1. Definition of Evolution
2. Theories of Human Evolution
3. Fossil Evidence of Human Evolution
4. Anatomical Changes in Human Evolution

Definition of Evolution

Human evolution is therefore defined as the scientific process of change that the human species underwent over millions of years – the straying from its early primate beginnings to the contemporary Homo sapiens. Thus, the study of human evolution is important in comprehending the aspects of biological and cultural evolution that have come into play for Homo sapience’s development, and for exploring the aspects of genetics, morphology, and behaviour in the process. In this article, the several important events in human evolution, the major fossils and evolutionary theories, and the history of genetic studies it is worth understanding the issue better and realising all the stages that humanity went through.

Theories of Human Evolution

The theories on the evolution of man are given below:

Pre-Darwinian Theories

The first theories about the origin and development of humans included the discovered theory called Lamarckism, which claimed that the changes acquired by a species during an organism’s lifetime could be inherited. It was Lamarck who came up with the thinking that if an inherited trait is obtained during an organism’s lifespan then it shall be inherited by the next generation which had a hint towards modern evolutionary theories.

Darwin's Theory of Evolution

Overcoming the theory of evolution, which was also at the centre of works attributed to Buffon and Lamarck, Charles Darwin disseminated the theory of Natural Selection, indicating that those species that are most suitable for given habitat conditions are most likely to experience reproduction. Common descent was also proposed by Darwin to mean that all organisms, including human beings, must have descended from the same ancestor.

Modern Synthesis

The splitting of the Modern Synthesis established the concord of Darwin’s natural selection along with genetics with a triad of genetics, palaeontology, and systematics. This framework pointed out the fact that evolution worked based on genes or variations between the alleles in populations, which enhanced knowledge regarding the way evolution influenced human beings and other species.

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Fossil Evidence of Human Evolution

The Fossil evidences are listed below:

Early Hominins

Sahelanthropus tchadensis which is approximately 7 million years old is one of the oldest hominins, with early signs of upright walking and a small brain case.

The approximately 6 million-year-old Orrorin tugenensis has traits indicating it to be bipedal, however has features of both apes and humans.

Australopithecus

Australopithecus afarensis like the famous specimen AL-288-1 also known as Lucy existed about 3. dated to 5 million years ago with evident features of pra bipedality and rather small brain size.

Australopithecus africanus was identified to have lived about 2. About 5 to 2 million years ago, more progression to the characteristics that define modern man is observed.

Genus Homo

This Includes:

Homo habilis

It is generally considered that Homo habilis was the first representative of our genus, which emerged about 2. About 4 million years ago it was even more developed in terms of its tool-using ability and also possessed a larger brain volume.

Homo erectus

Homo erectus has been known to have existed roughly around 1. From 9 million to 110000 years ago and showed some major development in technology and also the size of the human body.

Homo neanderthalensis

Neanderthals or Homo neanderthalensis appeared about 400,000 years ago and became extinct 40,000 years ago exhibiting complex tool use and capabilities of symbol use. Neanderthals are not regarded by scientists as a distinct species, but rather as a subspecies of humans.

Homo sapiens

The latest species of the genus Homo, Homo sapiens, appeared approximately 300 mya and is noted for higher intellectual potential and cultural evolution.

Important Fossil Discoveries

Fossils are very important in comprehending man’s evolution process. The timeline of these discoveries is outlined to show major events in the understanding of human evolution.

Anatomical Changes in Human Evolution

The anatomical changes with evolution are described below:

Bipedalism

Changes in Skeletal Structure: Use of the terrain for walking and other related activities brought with it some real beneficial changes like tilted foramen magnum hence a better balanced vertebral column, bow-shaped vertebral column, wider pelvis, and long limbs especially thighs and legs compared to arms. These adaptations provided a way through which a human being could be in an upright posture and walk.

Advantages of Bipedalism: Many benefits come with bipedalism some of which are, the energy-efficient way it is compared to four-legged walking or running over long distances, flexibility when it comes to holding objects and the use of hands, and also ease when spotting potential threats and resources in the environment.

Brain Size and Cognitive Development

Comparison of Brain Sizes: People’s brain size has grown over millions of years from 400cc in early hominins to over 1300cc in modern Homo sapiens.

Development of Language and Tools: The former is associated with a relative increase in the size of the brain and such higher intellectual processes as the utilization of complicated language and improved tool-making.

Dentition and Diet

Changes in Teeth and Jaw Structure: With the progression of human ancestors, there have been considerable alterations involving dentition and jaw structure that include; small-sized molars and premolars, and parabolic dental arcades. These changes are related to a transition from a mostly plant-based diet that is characteristic of early humans to a diet containing meat and cooked foods.

Dietary Adaptations: Such changes mean adaptations to any shift in diet, as well as the usage of tools and other methods to manipulate the food.

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