Evolution by Stages

Evolution involves gradual changes from simple to more complex forms. Humans are believed to have developed from simpler forms. Evolution is hypothesized to have begun in the oceans billions of years ago. Darwin gave the theory of evolution. In his book -The Origin of Species, Darwin has stated that evolution has come through a series of natural selection. The theory emphasized the following points:

• Natural Selection
• Variation
• Struggle To Exist
• Survival of the Fittest

Evolution is the outcome of the interaction amongst the following five processes:

• Mutation
• Genetic Recombination
• Chromosomal Abnormalities
• Reproductive isolation
• Natural Selection

Stages in Human Evolution

The following are the stages of human evolution:

1. Dryopithecus

These are deemed to be the ancestors of both man and apes. They lived in China, Africa, Europe and India. The genus Dryopithecus refers to the oak wood apes. When Dryopithecus was alive, the tropical lowlands which it inhabited were densely forested, so the members could have predominantly been herbivores.

2. Ramapithecus

Their first remains were discovered from the Shivalik range in Punjab and later in Africa and Saudi Arabia. They lived in open grasslands. Two pieces of evidence confirm their Hominid status:

1. Thickened tooth enamel, robust jaws and shorter canines.
2. Usage of hands for food and defence and extrapolations of upright posture.

3. Australopithecus

The fossil of this genus was first discovered in 1924 in South Africa. They lived on the ground, used stones as weapons and walked erect. They were 4 feet tall and weighed 60-80 pounds.

4. Homo Erectus

The first fossil of Homo Erectus was found in Java in 1891. These were named as Pithecanthropus Erectus. These were considered as the missing link between the man and apes. Another discovery made in China was the Peking man. This specimen had large cranial capacities and is believed to have lived in communities. Homo erectus used tools comprising quartz. Tools made of bones and wood were also discovered. There is evidence of collective huntings. There is also evidence of the use of fire. The Homo Erectus is believed to dwell in caves.

5. Homo Sapiens Neanderthalensis

The Homo Erectus evolved into Homo Sapiens. During evolution, two sub-species of Homo Sapiens were identified- Homo sapien Neanderthal and Homo sapiens sapiens. The cranial capacity of Neanderthal grew from 1200 to 1600 cc. Some small hand axes had also been discovered. This species of hominids could hunt big names such as mammoths.

6. Homo Sapiens Sapiens

The remains of Homo Sapiens were first discovered in Europe and were named Cro-Magnon. In these, the jaws are quite reduced, the modern man’s chin appeared, and the skull was rounded. Their cranial capacity was about 1350 cc. They gathered food through hunting. Art first appeared during this time.

This is how evolution took place.

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