free booknotes online
PinkMonkey Online Study Guide-Biology

12.1 Palaeontological Evidences -Our Ancestors

Fossil records of human evolution is quite incomplete and we have much to learn yet. In 1863, T.A. Huxley explained human evolution in his book Manís Place in Nature. In 1871, Charles Darwin published his ideas of human evolution in the book The Descent of Man. Later on many attempts have been made to find the missing link between man and ape in the form of an original creature or its fossil. Eugene Dubo unearthed the first fossil record of an ancestor of man in the form of a small part of skull and jaw bone. Between 1920 to 1930 many human-like fossils were found in China called "Peking Man" or Sinanthropus. But these fossil evidences do not form a neat chain of links leading from ancient ape to the modern human.


It appears from the fossil evidence, that human and apes have both descended from a common ancestor, called Dryopithecus, that lived over 20 million years ago. At about the same time the first human-like fossils were found in India and Africa in the form of such primate genera as Ramapithecus and Sivapithecus. The arrangement of teeth was like our own, indicating that Ramapithecus was one of our ancestors. The next known genus Australopithecus africanus (1.5 to 3 millions years ago) appeared in Africa. It had a rounded skull with a brain capacity of 450 to 700 cm3 (compared to 1000 to 2000 cm3 for humans), apparently walked upright, and was about 5 feet tall.

Some controversy still exists about these human ancestors and the gaps in evolutionary sequence, because the relevant fossils are rare, the remains did not survive until now, or have not yet been found.

There is less controversy over the more recent stages of human evolution. The fossils are more abundant and there are fewer gaps. They show that Homo erectus, the first known member of our genus, followed Australpithecus. Some 2 to 3 million years ago Homo erectus emerged as an erect, bipedal creature, with a receding forehead and human-like skeleton. Remains of H. erectus have been found in Africa, South East Asia and China.

The first fossil that belongs to our own species, Homo sapiens, appeared as recently as 100,000 to 40,000 years ago, and resembles us so closely that we call it human (Fig. 12.2). Homo sapiens survived as a result of erect bipedal posture, increased manual dexterity, feet suited for walking and running, and better developed creative brains.

Archeological records of human evolution indicate that early humans started out as small bands of hunters who killed animals for food and supplemented this with foraged and gathered items. The hunt-gatherer cultures allowed humans to exploit agriculture, about 10,000 years ago. Humans began to farm seriously around 8,000 BC and there was full fledged agriculture in many places just after 4000 BC. The agriculture allowed establishment of stable populations, and the development of technology permitted the survival and growth of human population.

 

Table of Contents

12.0 Introduction
12.1 Palaeontological Evidences - Our Ancestors
12.2 Ancestral Forms of Homo Sapiens

Chapter 13





Google
  Web PinkMonkey.com   

All Contents Copyright © PinkMonkey.com
All rights reserved. Further Distribution Is Strictly Prohibited.


About Us
 | Advertising | Contact Us | Privacy Policy | Home Page
This page was last updated: 5/9/2017 9:55:30 AM