Theory of biogenesis, PL-SQL Programming

THEORY OF BIOGENESIS -

  • This theory explains that the existing living organisms originated from pre-existing living beings not from non living entities.
  • This concept of origin of life was supported by various evolutionists on the basis of their experiments.
  • All such evolutionists have rejected the concept of autogenesis or abiogenesis.
  • F. Redi (1626-98) conducted an experiment in which he cooked some meat so that no organisms were left alive and placed them in three jars; one jar left uncovered, one jar was covered with muslin cloth and the third jar covered with parchment paper.
  • After a week, he observed that maggots appeared only in that jar which was uncovered not in those jars that were covered by either muslin cloth or parchment paper.
  • He concluded that flies arise from the eggs laid down by parent flies in the uncovered jar. On the basis of this experiment Redi had discarded the concept of spontaneous generation.

1543_theory of biogenesis.png

  • Lazzaro Spallanzani (1729-99) prepared a nutritive broth of vegetables and flesh and placed it in flasks and sealed the necks of the flasks just to check the entry of air. He boiled the broth for four hours and left these flasks as such for many days.
  • He observed that no living organisms appeared in broth of flasks and hence he concluded that microorganisms are formed not spontaneously, but from those already present in the air.
  • Louis Pasteur (1822-95) refused the concept of spontaneous generation on the basis of an experiment.
  • He has taken a mixture of sugar and yeast syrup and put this mixture into S-shaped flask.
  • The contents of the flask were boiled till steam passed out the tube and then they were cooled.
  • Pasteur did not found any change in the content of the flaks after a considerable longer period of time and no growth of organisms was observed.
  • He concluded his experiment with an inference that when the air entered the flask, all air-born particles got stuck at the bend of the tube and only the pure air reached the syrup that remained sterile.
  • He broke the neck of the flask.
  • This made a direct contact of syrup with the air and a thick growth of microorganisms appeared in the flask.
  • By this experiment and result, Pasteur conclusively disproved the idea of spontaneous generation.

1857_theory of biogenesis1.png

Posted Date: 10/8/2012 8:38:24 AM | Location : United States







Related Discussions:- Theory of biogenesis, Assignment Help, Ask Question on Theory of biogenesis, Get Answer, Expert's Help, Theory of biogenesis Discussions

Write discussion on Theory of biogenesis
Your posts are moderated
Related Questions
Example of COALESCE operator Example: Give the total of marks for each exam (simplified solution) SELECT CourseId, COALESCE ((SELECT SUM (Mark) FROM EXAM_MARK AS EM

Using the BULK COLLECT Clause The keywords BULK COLLECT specify the SQL engine to bulk-bind output collections before returning them to the PL/SQL engine. You can use these ke

Restriction and AND - SQL Restriction is available via the WHERE operator, and so it is in SQL. However, by Example showing how a certain simple restriction can be expressed u

Using Aggregation on Nested Tables Example is the most direct translation of its counterpart in the theory book that can be obtained in SQL but it is so over-elaborate that no

Data Types in SQL SQL's concept does not differ significantly from that defined in the theory book, apart from that business concerning NULL. However, the theory book equates

Opening a Cursor Opening the cursor executes the query & identifies the result set that consists of all rows that meet the query search criteria. For the cursors declared usin

Example of Null operator - NiNo Rule If we wanted to make HIGHER_OF adhere to "NULL in, NULL out"-let's call it the NiNo rule-we would have to write something like what is sho

Example of Shorthand for a row constraint Example: Shorthand for a row constraint ALTER TABLE EXAM_MARK ADD CONSTRAINT Mark_in_range CHECK (Mark BETWEEN 0 AND 100);

How Exceptions Are Raised By the run-time system, the internal exceptions are raised implicitly as are user-defined exceptions that you have related with an Oracle error number

Number Types The Number types permit you to store the numeric data (real numbers, integers, and floating-point numbers), show quantities, and do computations. BINARY_INTEG