Pre-Mendelian or each region’s requirements

 

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Premendal theory of heredity

introduction

The transfer of details, such as the variation and variation of characters from one person to his or her offspring or the next generation, is mainly known as a direct descendant of the gene, Inheritance.

Pre-Mendelian or each region’s requirements

Several theories about heredity were put forward before Gregor Mendel. These theories explained what physical form passed from parents to their children. These theories suggest that children’s characters are a mixture of parental characters. So, they are known as the principle of mixed inheritance.

VapourTheory

  • Proposed by the Greek philosopher, Pythagoras
  • Proposed in 500 BC
  • It states that each organ of an animal emits vapor and new offspring are formed by combining vapor from different organs.

Fluid theory

  • Proposed by the Greek philosopher and scientist, Aristotle
  • There were mainly four principles

(i) Man’s semen is pure form of blood

(ii) A woman’s menstrual fluid is not a more pure form of blood in the form of semen or female semen.

(iii) Two liquids combine during sexual intercourse

(iv) Male semen provided form and vitality to the fetus and female semen provided inert substance to form the fetus.

Reform principles

1. Boy Anton von Leuvenhoek

Observed human sperm and saw them wrinkle in semen and called them animalcules.

He proposed that each sperm is a potential human and develops into a new person when it is brought into a woman’s womb.

Since the lineage could not explain the inheritance of the characters

2. Principles of sperm and ovaries

Swamardam, Malpighi (1673), Hartsoyker (1694), Dalmpitius (1694), and Roux (1888) and it was therefore proposed that miniature animals were present in gametes and development was in front of miniatures. This short form was called a Midget.

Spermist theory

Some believed that homunculus was present in the spermatozoa. They were called spermists.

Ellipse theory

Some believed that homoculus was present in eggs. They were called ovists.

Particulate Theory

Proposed by French biologist Maupertius

It states that each animal produced minute particles for reproduction, and the union of these two parental particles produced a new individual.

Theory of pangensis

Proposed in 1868 by the famous English naturalist, Charles Darwin

He assumed a representative character Maddened Each part of the body is formed and transferred to the reproductive cells or gametes through the blood, and is therefore given to the child to guide the formation of the respective part. Young gets a mixture of penguins, so characters from both parents get a mix.

Rejected by Weisman in 1892.

Theory of continuity of germplasm

Germplasm Is immortal and is only passed from one generation to another. He tells somatoplasm When the organism dies and has no role.

The conclusion

Several theories were proposed before Gregor Mendel’s theories. But none of them prevailed due to insufficient physical and chemical details


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