Tag: Homo habilis

Introduction 

The origin and advancement in the physical features of human ancestors have been termed human evolution.  According to this theory, early humans went through a number of stages which converted them from prehistoric man to modern humans. Gradually the development in their brain size permitted them to use their physical attributes more skillfully. Early humans underwent many changes during the Neolithic period. They changed from hunters and gatherers to food producers, from living in trees or caves to becoming settlers, and from nomads to properly established people. Through this evolutionary process, humans developed the skill of managing resources efficiently and learnt the ability to remain in social work with other unknown individuals.

Evolution

Evolution is the gradual change in the inherited traits of  populations over many generations. These traits are the expressions of genes, which are passed down through from parent to offspring during sexual reproduction. This is the process by which a living organism changes and develops from their ancestors. Natural selection, mutation, gene flow, and genetic drift are a few of the methods which bring about evolution in a species. As a result of these processes, species emerge, grow, and adapt to their physical and social environments.

Evolution of Humans

Evolution of humans occurred from apes. Most scientists believe that humans and apes must have developed from the same creature because they share so many characteristics, such as long arms and a large brain. These  ape like creatures were called hominids.

Australopithecus Afarensis and Lucy

• The name Australopithecus refers to the earliest hominid. Australopithecus africanus, Australopithecus robustus Boisie, and afarensis are some of the different types of Australopithecus that have been identified through fossils.
• Australopithecus afarensis fossils have been discovered from Etopia.
• Experts have seen the last phase of bipedal movement in this species.
• Despite being able to stand upright, these humans still had certain ape-like characteristics.
• The most well-known Australopith is “Lucy“. It is a skeleton of Australopithecus afarensis which 3 million years ago was discovered in 1974 
• It was found by Donald C. Jhonson and his student Tom Gray at the site of Hardar in Ethiopia.
• While looking for animal bones, Johnson and Gray unintentionally discovered a little arm bone fragment and recognized that it belonged to hominids.

Homo Habilis

• The earliest known fossils of Homo are known as “homo Habilis,” and they were found in Kenya.
• The genus homo is different from Australopithecus, as its brain was bigger in size.
• Two million years ago, Homo Habilis possessed a larger brain that was nearly 800 cc in size.
• It was believed that Homo Habilis made various tools.
• They were first classified as members of the australopithecine family, but an in-depth research, later demonstrated that they should actually be considered early human specimens.

Homo Erectus

• A new species known as Homo Erectus emerged after the origin of Homo Habilis.
• It had a larger brain, that was 1000cc in size.
• They were considerably bigger and taller than Homo Habilis and now they could stand straight.
• Their grip improved as their fingers developed and this enabled them to firmly grasp objects.
• They began to travel enormous distances and build tools with great proficiency.

Homo sapiens Neanderthalensis

• Gradually Homo erectus perished nearly around 400,000 years ago.
• Around 125,000 years ago, a new species of Homo appeared on the human evolutionary process the Homo Neanderthals or Homo sapiens Neanderthals.
• In the 20th century, their fossils were discovered in Germany.
• Neanderthal brain continued to grow in size, and  evidence of ‘culture’ began to emerge
• However, Neanderthal skulls were very distinct from those of modern humans.

 Homo Sapiens Sapiens

• Then emerged the Homo sapiens sapiens, also known as the “thinking man” or “wise man,” from which modern humans evolved.
• They had a 1350cc brain, which allowed them to create more sophisticated tools.
• The homo sapiens sapiens began to interact with their social surroundings and live in groups.
• To dwell longer in a place, they started constructing proper and strong  shelters.
• They were likely the first living things to speak what we now refer to as language, and it proved to be helpful for them.

The Neolithic Revolution

• The beginning of the Neolithic period can not be traced to a particular date as it was emerging at different times in different places.
• It is one of the third stages of development and it saw a evolution in the early humans’ way of existence.
• The invention of agriculture was the most significant aspect of this period. Now, they no longer need to go around in quest of food because they have learned to cultivate their own food.
• Permanent settlements were eventually established as a result.
• Along with this, they now started to domesticate animals for their own purposes; this was also the time when the wheel was invented.

Summary

Human evolution is a long process and it took millions of years to transform primitive humans into present-day humans. As per numerous scientific investigations, it is thought that humans have developed from ape-like species. They could not even walk straight and they used to live like animals. As the brain grew in size over time, the evolution of the homo sapiens began. Their social conduct also evolved gradually. Additionally, they developed excellent toolmaking skills. Humans could also store knowledge due to their more advanced brains. This enhanced the speed of cultural adjustment and now modern humans were no more dependent on biological advancements.

Frequently Asked Question

1. What color was the original human being on earth?
Ans: Early humans had a pale skin, similar to the chimpanzee(closest relative of humans), . Dark skin was first a feature of early Homo sapiens which developed between 1.2-1.8 million years ago.

2. How come people have two legs?
Ans: One of the factors, that allowed humans to evolve from their prehistoric ape-like forebears was the ability to walk on two legs. Being able to move around on two legs saved energy and freed up the arms for tasks like hunting, making simple tools, and interacting with objects.

3. Are there still Neanderthals existing?
Ans: Around 430,000 years ago, fossils resembling Neanderthals were first discovered. The earliest Neanderthals are thought to have existed between 130,000 and 40,000 years ago, beyond which no physical proof of them can be found.

Introduction

The widely recognized nebular theory postulated that a massive cloud of dust including hydrogen and other gases created the solar system, including the planet earth. Small earthly particles like iron and nickel were created as a result of the earth’s contraction, rotation, and lowering of temperatures. The planet was created approximately 4.5 billion years ago after millions of years of precipitation and accumulation. Since then, the earth’s temperature has decreased, causing the crust to become more fragile. However, the earth’s interior core is still hot and igneous.

A short note on Prehistoric Earth’s Origin of Life

There were numerous theories about the origins of life on Earth. 

• According to the Panspermia theory, some scientists thought life originated from spores that came from outer space, while others hypothesized that it originated from decomposing materials like dirt, straw, etc (Spontaneous generation theory). Different experiments were carried out by various scientists, and they all disproved the hypothesis of spontaneous generation. 
• Later in 1953, Oparin and Haldane advanced the theory that life emerged from pre-existing non-living organic molecules like RNA, DNA, and other similar molecules because of abiotic chemical reactions.
• Numerous studies have suggested that RNA came before DNA, even though it is still unclear what replicating molecule was the earliest. Because RNA molecules can self-replicate and are simpler than DNA, they are considered autocatalytic.

Precambrian Life

The Precambrian period includes the Archean and the Proterozoic eons from 4.6 billion years to 542 million years. Most of the life that existed during the Precambrian period were prokaryotic organisms. Microfossils that looked like stromatolites and cyanobacteria from the Precambrian epoch first revealed the presence of life about 3.8 billion years ago (layered mounds). Additionally, the absence of oxygen in the early atmosphere rendered primitive organisms anaerobic. However, when cyanobacteria developed photosynthesis, it added oxygen to the atmosphere.

Eukaryotes, which have a nucleus, cytoskeleton, organelles, and mitotic spindle, first evolved around two billion years ago. It was once thought that endosymbionts like mitochondria and chloroplasts descended from bacteria. The evolution of eukaryotes benefited greatly from these endosymbiotic relationships.

Cambrian Explosion- Origin of Animal Diversity

The surge in the diversity of multicellular organisms during the early Cambrian epoch, which began 540 million years ago, is known as the Cambrian explosion. Tens of millions of years before the early Cambrian epoch, the first multicellular living forms began to appear as fossils. These ancient animals have diverse body designs from those of living creatures today. They vanished and were replaced by modern-day animal body types in the Cambrian fauna.

Evolution of Land Plants

The evolution of land plants from a green algal ancestor is a significant event in the history of life since it caused profound changes in the earth’s environment and the formation of the entire terrestrial ecosystem. The formation of land plants and the divergence of the four main surviving clades (liverworts, hornworts, mosses, and vascular plants) may have taken place during the late Ordovician and Silurian periods, according to evidence from fossil spores found in the mid-Ordovician.

Formation 

The majority of researchers concluded that the earliest life form and subsequent other life forms on earth appeared as a result of chemical evolution, or the production of molecules. The Nebular theory, developed by Immanuel Kant and Pierre Laplace, postulates that planets are formed by a cloud of hydrogen and helium. Clouds were created by tiny particle collisions, and the planet itself was created through accretion.

Evolutionary Milestones

• Life’s history is represented by several milestones. For instance, unicellular organisms first appeared on Earth, and ever since then, diversification has led to the emergence of complex living forms. These living forms will eventually go extinct and be replaced by other creatures. 
• Complex living forms evolve as a result of this evolution. According to some fossil research, numerous species began to independently become multicellular around 1 billion years ago, and animals started to grow hard portions in their bodies to survive on the earth. 
• Dinosaurs were the most prevalent class of creatures on the planet for millions of years. For a considerable amount of time, they dominated the prehistoric landscape before a disaster led to the extinction of dinosaurs.
• The Great Apes, from which humans emerged, was the next significant event. Human evolution is still clearly visible, although it has not yet reached its conclusion.

Presence of Humans

• The most well-known species, Homo sapiens, is a descendant of hominids, the first creatures that resembled humans. 
• According to several fossil records, archaeological findings, and embryological research hominids are thought to have diverged from other primate species in the southern and eastern African areas 2.5–4 million years ago. 
• As a result, they have bipedalism in common (the ability to walk on two legs).
• Additionally, as hominids evolved and adapted to their habitats, their brain sizes grew. Around 2.3 million years ago, Homo habilis, the earliest human-like hominid, had a brain size of 650–800 cc and started using stone tools.
• Fossils discovered in Java in 1891 revealed the existence of Homo erectus, the next stage of human evolution, some 1.5 million years ago. They have a 900cc larger brain due to evolution. Then they began to migrate from Africa to Eurasia, where they started to learn how to make fire and develop defenses.

Summary

The widely recognized Nebular Theory postulated that a massive cloud of dust, including hydrogen and other gases, created the solar system, including the planet Earth. The majority of scholars concluded that the earliest life form and subsequent other life forms on earth appeared as a result of chemical evolution, or the production of molecules. Dinosaurs were the most prevalent class of creatures on the planet for millions of years. The most well-known species, Homo sapiens, is a descendant of hominids, the first creatures that resembled humans.

Frequently Asked Questions  

1.What is Coal’s Formation Process? List the Types of Coal.
Ans. The layers of dead plants and animals underwent physical and chemical changes as a result of pressure and heat. Deposits rich in carbon were created as a result of this. Different forms of coal include lignite, bituminous coal, and anthracite.

2.Explain Index Fossils?

Ans. Index fossils are fossils that are used to identify geologic formations with broad regional distributions and short time scales. These fossils are numerous, dispersed, limited in geological time, and unique.

3.What Factors led to the Earth’s Changes?
Ans. Physical changes such as mountain development, tectonic movements, volcanic eruptions, climate changes, and biological changes on the planet resulted from the evolution of new life forms.

4.What are the Necessary conditions for Life to Sustain on Earth?
Ans. The necessary conditions for life to sustain on earth are as follows,

• Proper distance from the sun
• Presence of water and the atmosphere
• Existence of the lithosphere and biosphere
• Ideal temperature ranges (around 17 degrees Celsius).