Introduction of biology || Every Neet - 2021 Aspirants Must be Know

 Introduction of biology

Biology is the study of life or living organism. It is the story of life on the earth. Historically biological knowledge was ancillary knowledge of the human body and its function. The origin and growth of biodiversity the evolution of flora and fauna of different habitats etc.
The subject matter Got artificially divide into the sub-disciplines of botany and zoology and later into ever microbiology.
Meanwhile, physical science made heavy inroads into biology and established biochemistry and biophysics as new sub-disciplines of biology. Mendel,s work and its rediscovery in the early 20th century led to the promotion of the study of genetics. the discovery of the double-helical structure of DNA and the disappearance of the three-dimensional structure of many macromolecules led to the establishment of phenomenal growth in the dominating area of molecular biology.
At first, life comes in the water.


Father of biology-Aristotle




13 branches of biology

Biology - the study of life or living organism.


Physiology - the study of how organ work and organ systems function.


Evolutionary biology-study of the evolutionary process that produces the diversity of life on the earth how modern species have descended from their extreme ancestor.

Taxonomy-the naming and classification of the organism.

Cytology -the study of cell.

Ecology-study of how organisms interact with each other and their environment.

Genetics-study of heredity (how traits are passed down from parents to offspring)

Anatomy-study of the structure of organ and organ system.

Morphology-study of external features such as size shape color etc.

Palynology-study of the structure of pollen grain.

Virology-study of virus in all their aspects

 Bacteriology -the study of bacteria.

Biotechnology-utilisation of the living organisms in industrial process.

Origin of life

The universe is very old almost 20 billion years ago. the universe comprises the fuse cluster of galaxies and galaxies contain stars gas dust clouds.

Big Bang theory 

The Big Bang theory explains the origin of the universe. It talks about at a time a singular huge explosion and universe expand and temperature come down. After some time helium and hydrogen also come. The gases condense under gravitation and form the galaxies and Earth formed about 4.5 billion years back. And no atmosphere on the earth. the molten mass release the methane water vapor carbon dioxide and ammonia. And the UV rays which come from the sun on the earth broken water into hydrogen and oxygen and light H2 escape.oxygen combined with ammonia and methane to form water carbon dioxide and others. When ozone is formed the water vapor fell as rain. and to fill all the depression and form ocean and life appear almost four billion years back.


Origin of life 










Theory of special creation


The great supporter of this theory was father Suarez. Which based on conventional religious literature. This theory says that life was created by supernatural power. According to Bible the first man Adam and the first women eve were created by God
. Hindu mythology says that the world was created by God Brahma. Special creation theory lacks scientific evidence and an account of which it is not accepted.

Theory of spontaneous generation/ abiogenesis / autogenesis

This theory is given by Epicurus Aristotle and von helmet. According to this theory, life arises spontaneously out of nonliving matter. 
Examples: housefly arise from dung, frog developed 
from rainwater.
 Von helmont says that in 21 days rats produced from wheat grain kept in the earthen pot along whit a shirt drenched in sweat.
But this theory was disproved by many scientists 
They prove that life comes from only pre-existing life.
The scientist who experimentally challenged the theory was Francesco Redi, Lazzaro Spallanzani, Louis Pasteur. this theory is disproved because they can scan not that how the first life form come on earth.
  

Louis Pasteur


Francesco Redi


Lazzaro Spallanzani








Theory of panspermia/ cosmozok theory


This theory was given by Greek thinkers.
The thought unit of life called spores was transferred to the different planets including earth. it was also believed that come out decaying and rotting matter like straw and mud etc.
Certain scientists criticize this theory by saying that spores of life can't survive in the outer atmosphere because of extreme dryness high-temperature UV rays.

'Operation and Haldane's theory of the origin


Oprin from Russia and Haldane from England both say that life could have come from pre-existing Life non-living organic molecules such as ( RNA, protein), etc.

It is also called the chemical theory of the origin of life aur theory of artificial synthesis or materialistic theory (oprin).Oprin was a Russian biochemist who wrote the book 'origin of life.
Haldane was an English physiologist who settled in India in Bhubaneswar. He wrote the book ' the enzyme'.


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