Human Reproduction: Male and female reproductive systems

Human evolution, the method with the aid of using which people evolved on Earth from now-extinct primates. Viewed zoologically, we human beings are Homo sapiens, a culture-bearing upright-taking walks species that live at the ground and possibly first developed in Africa approximately 315,000 years ago. We at the moment are the most effective dwelling participants of what many zoologists talk to because of the human tribe, Hominini. However, there may be considerable fossil proof to suggest that we had been preceded for tens of thousands and thousands of years with the aid of using different hominins, including Ardipithecus, Australopithecus, and different species of Homo, and that our species additionally lived for a time contemporaneously with as a minimum a different member of our genus, H. neanderthalensis (the Neanderthals).

Introduction

In its simplest sense, evolution means the slow process of change from a simple structure to a more complex one. Evolution assumes that all living things are interconnected. Humans are said to have evolved from some simpler forms. Most scientists today accept the basic principle of evolution but have different views on how evolution occurred or how far advanced it went.

The scientific establishment of the theory of evolution was mainly the work of Charles Darwin. In his book, ‘The Origin of Species 1859 Charles Darwin showed that human evolution or evolution of human beings has occurred through the process of natural selection.

1. 1.    Natural selection: It is the system of evolution of a species wherein characteristics which assist character organisms to live on and reproduce are surpassed directly to their offspring.
2. 2.    Struggle for the existence: Organisms multiply in geometric ratio, however the area and meals continue to be fixed leading to competition from the survival. Increase withinside the quantity of species results in an opposition referred to as conflict for existence.
3. 3.    Survival of fittest: According to Darwin, withinside the conflict for existence, the fittest people survive Andre product, even as the undeserving man or woman perish.
4. 4.    Variation: According to Darwin, beneficial versions seem in each generation and are inherited from one generation to another.

Stages in Human Evolution/ Human Evolution Timelines

The Human Evolution Timelines describes the most important events in the evolutionary line of modern human nature, Homo Sapiens, along with the history of life, from about 4 billion years to before recent evolution within H.sapiens during and since the last ice age.

Dryopithecus

It is the 1st  stage of human evolution or evolution of human beings. This genus lived in Africa, India, China, and Europe. The meaning of the genetic title Dryopithecus is oak wood apes. This is because it is believed that the environmental conditions at that time were densely forested tropical lowlands and the members were predominantly herbivorous.

Ramapithecus 

It is the 2nd stage of human evolution or evolution of human beings. The first remains of Ramapithecus were found from Shivalik hills in Punjab. Then it was discovered in Africa and Saudi Arabia. The region where Ramapithecines lived was not merely forest but open grassland. A hominid status for them is claimed on 2 grounds: Fossil evidence indicates the adaptation which includes robust jaws, shorter canines, and thickened tooth enamel. Extrapolation concerning upright posture and also the use of hands for food and defense.

Australopithecus 

It is the 3rd  stage of human evolution. This genus is the immediate forerunner of the genus Homo. The first Australopithecine was found in 1924 at Taung (a limestone quarry site in South Africa), by Raymond Dart. They walked erect and lived on the ground. Probably they use stones as weapons to hunt small animals. They weighed was around 60 to 90 pounds and height were about 4(four) feet tall.

Homo Erectus

It is the 4th stage of human evolution. The first evidence of the Homo species was discovered in Java in 1891 by Eugene Dubois. He named this Pithecanthropus Erectus which means the erect ape-man. Another evidence was found in China, South-West of Peking called Peking man. They had larger cranial capacity in comparison to the Australopithecus who lived in communal existence. They also used fire. The cranial capacity of Homo erectus includes Java man and Peking man are varied from about 775 to 1300 CC.

Homo Sapiens Neanderthalensis

It is the 5th stage of human evolution. The Homo Erectus were slowly evolved into the Homo Sapiens. In this transitional event, the two subspecies of the Homo Sapiens have been recognized.

1. The primitive man who has been labeled Homo Sapien Neanderthal. 
2. The modern man is termed Homo Sapiens sapiens.

Most of the evidence related to the primitive man that has been unearthed is almost 75,000 years old. The 1st  fossil that was found of the Neanderthal type was a skull cap which was found in Germany. The cranial capacity of Neanderthal exceeded that of the modern man. Its range is varied from 1200 to 1610 CC. Their culture is known as Mousterian culture.

Homo Sapiens Sapiens: 

The first skeletal remains of Homo sapiens were found in Europe and were named Cro-Magnon. within the Homo sapiens, there’s the final reduction of the jaws, the looks of contemporary man’s chin, and the rounded skull. Mean cranial capacity was about 1350 CC. Modern man is extremely close regarding Cro-magnon.  Their culture that dates back to 35,000 years is additionally referred to as the period culture.