Interesting Facts About Evolution

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Define Evolution

First theory of evolution was proposed by Jean Baptiste de Lamarck(1744-1829) in the book Philosophie Zoologique. Term biology was also given by Lamark and treviranus. As per this theory evolution is a slow and gradual process, which explains and makes us understand the living world around us. This process takes time as it depends upon various factors. 


Factors Causing Evolution as per Lamarckism Theory

There are various factors which leads to evolution in an organism, some of these are given below:

  1. Internal Vital Forces: Some internal forces are present in all organisms. By the presence of these forces, organisms have a tendency to increase the size of their organs or entire body.

  2. Effect of environment and New Needs: Environment influences all types of organisms. Changing environment gives rise to new needs. New needs or desires produce new structure and change habits of the organism.

  3. Use and Disuse of Organs: If an organ is constantly used, it would be better developed whereas disuse of the organ results in degeneration.

  4. Inheritance of Acquired Character: During life time of an organism new characters develop due to internal vital forces, effect of environment, new needs and use and disuse of organs.

These acquired characters are inherited from one generation to another. By continuous inheritance from one generation to the next generation tends to make the next generation quite different from its ancestor resulting in the formation of new species.


Example in Support of Lamarckism

  1. Long neck and high fore limb of Giraffe.

  2. Aquatic birds stretched their toes and developed a web.

  3. Snake lost its legs.

  4. Deers became good runners by the development of strong limbs and streamlined bodies.

  5. Retractile claws of coronavirus animals.


Charles Darwin Theory of Evolution

According to Charles Darwin, the main concept behind evolution is natural selection. This theory was later explained by Darwin in his book ‘On the origin of species by the means of natural selection’(1859).

Main Features of the Theory of Natural selection are as follows:

  1. Overproduction: All organisms have capability to produce enormous numbers of offsprings, organisms multiply in geometric ratio. Example: Plants produce thousands of seeds, Insects lay hundreds of eggs, etc. 

  2. Struggle for Existence: Every individual competes with others of the same and other species for basic necessities like space, shelter and food. It is called the struggle for existence and it continues for the whole life from zygote stage to its natural death.

  3. Variation and Heredity: Except the identical twins no two individuals are similar and their requirements are also not same. It means there are differences among individuals. This difference is called variation.

  4. Survival of Fitness or Natural Selection: Most suitable and fit individuals are successful in the struggle for survival.

  5. Origin of New Species: Darwin explained the variations appearing due to the environmental changes are transmitted to the next generation. So offspring become different from ancestors. In the next generation the process of natural selection repeats so after many generations new species are formed.


Facts Regarding Evolution

  1. Huxley explained the origin of man in his book ‘ The man’s place in nature’.

  2. Humans are a member of order primates of class mammalia.

  3. Primates originated 80-100 million years ago in the Pliocene epoch of the Cenozoic era.

  4. Primates originated from elephant shrews but they were not real primates. 

  5. Apes have 48 number of chromosomes whereas 46 number of chromosomes.

  6. DNA content and DNA matching is the same in both apes and humans.

  7. Homo habilis were the first human- like species as their fossils were discovered by Dr. Leakey from two million years old rocks in Africa. Their cranial capacity is about 650-800 c.c.

  8. Homo erectus were direct ancestors of homo sapiens. They are also called java man and their cranial capacity is 800-1000 c.c. They were the first man who used fire for hunting, protecting and cooking. Their origin and evolution, 1.5-2 million year ago.

  9. Homosapiens origin and evolution before 40,000- 1 lakh year ago.

  10. Fossils of homosapiens were discovered by C.fulhrott from the Neanderthal valley of germany.

  11. Old world monkeys are more closer to humans as compared to new world monkeys.

  12. Chimpanzees are the closest ape to humans.

  13. Every living entity has evolved from a bacterium which lived billions of years ago. It is said that biological evolution started around 3.7 billion years ago.

  14. Darwin finches are also an example of adaptive radiation(different shape of beak and claws due to their habitat). 

  15. Darwin finches are an example of allopatric speciation.

  16. Study of fossils is known as paleontology.

  17. Geological time scale divides into 6 eras: Azoic, Archaeozoic, proterozoic, Palaeozoic, Mesozoic, Coenozoic.

FAQ (Frequently Asked Questions)

1. Explain the term Evolution?

Ans. First theory of evolution was proposed by Jean Baptiste de Lamarck(1744-1829) in the book Philosophie Zoologique. Term biology was also given by Lamark and treviranus. As per this theory evolution is a slow and gradual process, which explains and makes us understand the living world around us. This process takes time as it depends upon various factors.

2. Write Classification of Man?

Ans.

Phylum: Chordata

Class: Vertebrata

Order: Mammalia

Subclass: Eutheria

Order: Primates

Suborder: Anthropoidea

Super family: Hominidae

Family: Hominidae

Genus: Homo

Species: sapiens

3. Write few facts regarding Evolution of Humans?

Ans. 

  1. Huxley explained the origin of man in his book ‘ The man’s place in nature’.

  2. Humans are a member of order primates of class mammalia.

  3. Primates originated 80-100 million years ago in the Pliocene epoch of the Cenozoic era.

  4. Primates originated from elephant shrews but they were not real primates. 

  5. Apes have 48 number of chromosomes whereas 46 number of chromosomes.

  6. DNA content and DNA matching is the same in both apes and humans.

  7. Homo habilis were the first human- like species as their fossils were discovered by Dr. Leakey from two million years old rocks in Africa. Their cranial capacity is about 650-800 c.c.

  8. Homo erectus were direct ancestors of homo sapiens. They are also called java man and their cranial capacity is 800-1000 c.c. They were the first man who used fire for hunting, protecting and cooking. Their origin and evolution, 1.5-2 million year ago.

  9. Homosapiens origin and evolution before 40,000- 1 lakh year ago.

  10. Fossils of homosapiens were discovered by C.fuhlrott from the Neanderthal valley of germany.