INTRODUCTION TO HUMAN EVOLUTION

The lengthy course of change that separated humans from their apelike predecessors is known as human evolution. According to scientific research, the physical characteristics and behavioural features that all humans share have their roots in apelike ancestors and have been evolving for almost six million years.

Bipedalism, or the capacity to walk on two legs, originated more than 4 million years ago and is one of the early characteristics that distinguishes humans. Other crucial human traits, such a large and complex brain, the capacity for language, and the ability to create and utilize tools, emerged relatively recently. The previous 100,000 years have seen the emergence of many advanced qualities, such as complex symbolic expression, art, and rich cultural diversity.

Primates are what we are as humans. The contemporary human species, Homo sapiens, has a very close kinship to another group of primate species, the apes, as evidenced by physical and genetic similarities. A common ancestor of humans and the big apes (giant apes) of Africa, including bonobos (sometimes known as "pygmy chimpanzees") and gorillas, lived between 8 and 6 million years ago. Africa was the place where humans first began to evolve, and it was also the site of much of that evolution. All of the early human fossils that date between 6 and 2 million years ago are from Africa.

About 15 to 20 separate species of early humans are currently recognized by the majority of scientists. But there is disagreement among scientists over the relationships between these species and which ones just went extinct. There are no living descendants of many early human species—certainly the bulk of them. As well as the classification and identification of certain early human species, researchers disagree on the causes of each species' evolution and demise.

Between 2 million and 1.8 million years ago, the earliest members of the human species made their way from Africa to Asia. They arrived in Europe about 1.5 million and 1 million years later. Many regions of the planet were colonized by modern human species much later. For instance, it is likely that humans first arrived in Australia just 60,000 years ago and in the Americas around 30,000 years ago. Within the last 12,000 years, agriculture initially appeared and the first civilizations emerged.

Paleoanthropology

The scientific study of human evolution is called paleoanthropology. A branch of anthropology, which is the study of human culture, society, and biology, is paleoanthropology. Understanding the genetic, physical, physiological, and behavioral similarities and differences between humans and other species is a key component of the field. Paleoanthropologists look for the origins of human behavior and physical characteristics. They are interested in learning how evolution has influenced everyone's abilities, tendencies, and limitations.

The most significant hints concerning this ancient past can be found in early human fossils and archaeological relics. These remains include bones, tools, and any other traces that earlier humans may have left behind, such as footprints, indications of hearths, or butchering markings on animal bones. The remains were typically buried and preserved organically. Then, they are discovered either by digging in the subsurface or on the surface (exposed by rain, rivers, and wind erosion). Scientists can learn about the physical characteristics of ancient humans and how they changed by examining preserved bones. 

Bone size, shape, and muscle marks provide information about how those ancestors moved, wielded tools, and experienced long-term changes in brain size. The items manufactured by earlier humans and the locations where they were discovered are referred to as archeological evidence. Archaeologists can learn how early humans manufactured and used tools and lived in their environments by examining this kind of evidence.

The Process of Evolution

The process of evolution involves a number of unavoidable changes that lead to the emergence of new species (populations of various creatures), their environmental adaptation, and eventual extinction. Every species or organism has its roots in the biological evolution process. The term "species" refers to a group whose adult members routinely interbreed, generating viable offspring—that is, offspring capable of reproducing—in sexually reproducing animals, including humans. Each species is assigned a distinctive, two-part scientific name by scientists. Modern humans are categorized as Homo sapiens under this concept.

The genetic material—the chemical molecule, DNA—that is inherited from the parents changes throughout time, and this is especially true of the ratios of various genes in a population. Genes are the sections of DNA that contain the chemical instructions needed to make proteins. Mutation is the process by which the DNA's information can alter. Particular genes' expression, or how they affect an organism's structure or behavior, can also alter. Genetically inherited traits can affect the likelihood of an organism's survival and reproduction because genes determine how an organism's physiology and behavior evolve over its existence.

Evolution does not affect just one individual. Instead, it modifies the hereditary growth and development mechanisms that characterize a population (a collection of members of the same species living in a single habitat). Parents impart adaptive mutations to their children, which eventually spread throughout the entire population. As a result, the offspring acquire those genetic traits that increase their likelihood of surviving and capacity for reproduction, which may be effective up to a change in the environment. A species' general manner of life, including what it eats, how it grows, and where it may live, might change throughout time as a result of genetic change.

Reference:

 Introduction to human evolution. (2022, July 11). The Smithsonian Institution’s Human Origins Program. https://humanorigins.si.edu/education/introduction-human-evolution