Posted: February 1st, 2023

Human Evolution and Mitochondrial DNA Studies

The human lineage has evolved from apes nearly six million years ago. Based on the fossil evidence data, the evolution of humans occurred in Africa, but still, it is not clear that the genus Homo appeared was in Southern or Eastern Africa. Recently genetic studies showed that modern humans migrated from Africa and started to colonize different parts of the world around 60,000 years ago. The details of the fossil and the archeological evidence give us the important clue about the past. These include remains of bones and the tools used by the people in the past which were buried naturally. By studying the fossilized bones, scientists had an idea about the physical appearance of the bone and how it changed over time. Similarly, archaeologists studied the man-made tools used earlier and how did they survive. Another way of identifying the origin of modern humans is by studying the mitochondrial DNA all over the world. As we all know that mitochondrial DNA (mtDNA) is inherited from the mother and not the father, the resulting evidence suggest that mtDNA inherited from thecommon ancestor who believed to be lived in Africa around 160,000 years ago.

Hominins:
Hominins include our species Homo sapiens and now-extinct species of Homo. The important feature observed in all hominins is bipedalism, a habitual means of locomotion. Early hominins were ape-like above the neck, had smaller brains and large teeth and jaws, unlike modern humans.

a. Very early hominins: Three species were identified:

Sahelanthropus tchadensis: It has been evolved seven million years ago, the ancestor of modern humans. A single piece of this genus was identified in Chad and the fossil was called “Toumai”.

Orrorin tugenensis: It was recently discovered in the year 2000. The feature of this hominin is similar to modern humans than the Australopiths.

Ardipithecus: It is bipedal which was discovered in the year 1990. b. Genus Australopithecus (Early Hominins):This ape has evolved around four million years ago and was reported to be extinct around two million years ago. The characteristics features of Australopithecus were similar to modern humans. Males were 50% larger when compared to females and the size of the brain is relative to its body mass. They are bipedalism, but still, some were arboreal. The footprints of Australopithecus were found in Tanzania and Laetoli around 3.6 million years ago. Many species of Australopithecus have been identified, of which Australopithecus afarensis lived around 3.9 million years ago. The “Lucy”, the fossil name is considered to be significant because nearly 40% of the skeleton was recovered.

c. Genus Paranthropus: These hominids are big and have large grinding teeth. The molar teeth showed heavy wear that helps in grinding a vegetarian diet. The species of Paranthropus include P. robustus from South Africa and P. aethiopicus and P. boisei from East Africa. They are not considered as ancestors of modern humans and became extinct one million years ago.

d. Early Hominins: Genus Homo: The genus Homo is reported to have appeared between 3.0 million years ago. Recently in 2010, a new species H. gautengensis was identified, and before that H.habilis was the oldest fossil identified in this genus. The features of H.habilis was similar to that of humans, it had a jaw that was slightly abnormal than the Australopithecus. The size of the brain is larger 600-750 cubic centimeters and had long arms. They are called handyman, due to the identification of stone tools in these fossil remains.

i. Homo erectus: They evolved around 1.8 million years ago in East Africa. They were the first hominin on the earth to migrate from Africa and their fossils were identified in various places like China, India, Java, and Europe. The features of the Erectus were similar to modern humans than H.habilis. They weighed around 65kg similar to that of modern humans. The size of the brain was larger 775-1100 cubic centimeters which is smaller than modern humans. The nose was facing downward similar to that of modern humans which is required to warm the cold air before I reach the lungs. These hominins have lived until around 50,000years ago. ii. Homo sapiens: It is evolved from H.Erectus around 50,000 years ago. Some of the species included are H. rhodiensis, H. hiedelbergensis, and H.neanderthalensis. The size of the brain is 1200-1400 cubic centimeters, similar to that of modern humans. They had a thick skull, receding chin, and brow ridge, and these hominins have survived around 30,000-10,000 years ago. The modern humans evolved from H.Erectusin Africa, then migrated from Africa around 100,000 million years ago. The modern humans replaced H. Erectus migrated to Europe and Asia in the first process.

Posted: February 1st, 2023

Human Evolution and Mitochondrial DNA Studies

The human lineage has evolved from apes nearly six million years ago. Based on the fossil evidence data, the evolution of humans occurred in Africa, but still, it is not clear that the genus Homo appeared was in Southern or Eastern Africa. Recently genetic studies showed that modern humans migrated from Africa and started to colonize different parts of the world around 60,000 years ago. The details of the fossil and the archeological evidence give us the important clue about the past. These include remains of bones and the tools used by the people in the past which were buried naturally. By studying the fossilized bones, scientists had an idea about the physical appearance of the bone and how it changed over time. Similarly, archaeologists studied the man-made tools used earlier and how did they survive. Another way of identifying the origin of modern humans is by studying the mitochondrial DNA all over the world. As we all know that mitochondrial DNA (mtDNA) is inherited from the mother and not the father, the resulting evidence suggest that mtDNA inherited from thecommon ancestor who believed to be lived in Africa around 160,000 years ago.

Human evolution:
The evolution of humans occurred from ancestors like Australopithecus and Homo habilis that had shared ancestors with apes and chimpanzees six million years ago.

Based on the fossil data, it has been found that humans did not evolve from monkeys but a shared ancestor with monkeys that neither looks like human nor monkey.

The term hominin refers to modern humans, including all our immediate ancestors like Australopithecus, Ardipithecus, and Paranthropus.

It is difficult to identify the true lines of ancestors in hominins but recent findings show that many new fossils that are identified are hominin species that are died and were not ancestral to modern humans. The below discussed are the different hominins that existed millions of years ago.

Hominins:
Hominins include our species Homo sapiens and now-extinct species of Homo. The important feature observed in all hominins is bipedalism, a habitual means of locomotion. Early hominins were ape-like above the neck, had smaller brains and large teeth and jaws, unlike modern humans.

a. Very early hominins: Three species were identified:

Sahelanthropus tchadensis: It has been evolved seven million years ago, the ancestor of modern humans. A single piece of this genus was identified in Chad and the fossil was called “Toumai”.

Orrorin tugenensis: It was recently discovered in the year 2000. The feature of this hominin is similar to modern humans than the Australopiths.

Ardipithecus: It is bipedal which was discovered in the year 1990. b. Genus Australopithecus (Early Hominins):This ape has evolved around four million years ago and was reported to be extinct around two million years ago. The characteristics features of Australopithecus were similar to modern humans. Males were 50% larger when compared to females and the size of the brain is relative to its body mass. They are bipedalism, but still, some were arboreal. The footprints of Australopithecus were found in Tanzania and Laetoli around 3.6 million years ago. Many species of Australopithecus have been identified, of which Australopithecus afarensis lived around 3.9 million years ago. The “Lucy”, the fossil name is considered to be significant because nearly 40% of the skeleton was recovered.

c. Genus Paranthropus: These hominids are big and have large grinding teeth. The molar teeth showed heavy wear that helps in grinding a vegetarian diet. The species of Paranthropus include P. robustus from South Africa and P. aethiopicus and P. boisei from East Africa. They are not considered as ancestors of modern humans and became extinct one million years ago.

d. Early Hominins: Genus Homo: The genus Homo is reported to have appeared between 3.0 million years ago. Recently in 2010, a new species H. gautengensis was identified, and before that H.habilis was the oldest fossil identified in this genus. The features of H.habilis was similar to that of humans, it had a jaw that was slightly abnormal than the Australopithecus. The size of the brain is larger 600-750 cubic centimeters and had long arms. They are called handyman, due to the identification of stone tools in these fossil remains.

i. Homo erectus: They evolved around 1.8 million years ago in East Africa. They were the first hominin on the earth to migrate from Africa and their fossils were identified in various places like China, India, Java, and Europe. The features of the Erectus were similar to modern humans than H.habilis. They weighed around 65kg similar to that of modern humans. The size of the brain was larger 775-1100 cubic centimeters which is smaller than modern humans. The nose was facing downward similar to that of modern humans which is required to warm the cold air before I reach the lungs. These hominins have lived until around 50,000years ago. ii. Homo sapiens: It is evolved from H.Erectus around 50,000 years ago. Some of the species included are H. rhodiensis, H. hiedelbergensis, and H.neanderthalensis. The size of the brain is 1200-1400 cubic centimeters, similar to that of modern humans. They had a thick skull, receding chin, and brow ridge, and these hominins have survived around 30,000-10,000 years ago. The modern humans evolved from H.Erectusin Africa, then migrated from Africa around 100,000 million years ago. The modern humans replaced H. Erectus migrated to Europe and Asia in the first process.