Life and its Origin
This note contains different theories of life in detail.They performed an experiment to conclude unicellular organism could not originate from nonliving things.
Summary
This note contains different theories of life in detail.They performed an experiment to conclude unicellular organism could not originate from nonliving things.
Things to Remember
- Life is the power that organisms possess to maintain their existence and reproduce themselves.
- Francesco Redi(1684) demonstrated to show maggots could not be formed from the flesh of meat, but the smell of meat attracted the flies which lay eggs.
- Louis parleus(1862) disproved the concept given by abiogenesis and performed the experiment with swan neck flask supporting biogenesis.
- They performed an experiment to conclude unicellular organism could not originate from nonliving things.
MCQs
No MCQs found.
Subjective Questions
Q1:
Define housing
Type: Very_short Difficulty: Easy
<p>The housing covers not only the meaning of Physical structure providing shelter but also the immediate surrounding and related community facilities and services. It is also known as a human settlement where people reside and pursue their family goals. Good and safe housing plays a vital role in the total welfare of the individual, family in the community.</p>
Q2:
Explain goal and criteria for housing
Type: Short Difficulty: Easy
<ol>
<li>Shelter</li>
<li>Family life</li>
<li>Access to community facilities</li>
<li>Family participation in community life</li>
<li>Economic stability</li>
</ol>
<p><strong>Criteria for Healthful Housing</strong></p>
<ol>
<li>Healthful housing provides physical protection and shelter</li>
<li>Provides adequate space for cooking , eating ,washing and excretory functions</li>
<li>It should be constructed in such a way that it could prevent the spread of communicable diseases</li>
<li>Protection from hazards of exposure to noise and pollution</li>
<li>Should be free from toxic or harmful material</li>
<li>Encourage personal and community development ,promotes social relationships, reflects a regard for ecological principles by these means promotes mental health.</li>
</ol>
Videos
No videos found.
Life and its Origin
Life is the power that organisms possess to maintain their existence and reproduce themselves. Various scientists proposed different theories regarding the origin of life. Some popular theories are discussed below;
Special Creation Theory
According to this theory, all plants and animals existing on the earth today are created by the supernatural power of a god.
Spontaneous generation theory(Abiogenesis or autogenesis)
Ancient Chinese, Greek and Egyptian believed in spontaneous generation of life. According to this, "Life is originated from nonliving things or abiotic factors gradually or automatically." Eg; frog, fish, snail were formed by clay.
Biogenesis
According to this theory, "the new organism is originated from pre-existing ones."
Redi's experiment
source: www.welchclass.com
Francesco Redi(1684) demonstrated to show maggots could not be formed from the flesh of meat, but the smell of meat attracted the flies which lay eggs. When eggs hatch, maggots appeared on meat. For that, he has taken 8 jars in which he kept a piece of boiled meat in all of them. 4 jars are made sealed whereas remainings are opened. He found the maggots in opened jars rather than sealed jars.
Lazzaro and spanllanzenil(1969)
They performed an experiment to conclude unicellular organism could not originate from nonliving things. For that 8 bottles are taken with heg influsion. 4 of them are corked and remaining are made air-tight. After few days, they found microorganisms in corked bottles not in air-tight bottles.
Louis experiment
Louis parleus(1862) disproved the concept given by abiogenesis and performed the experiment with swan neck flask supporting biogenesis.
Experiment;
- Pour the nutrient solution in swan neck flask.
- Bend the neck of the flask into S-shaped on heating.
- Boil the solution to kill and derive out bacteria.
- Cool, the solution and the dust particles trap in bending part solution becomes solute.
- Break the bending part. Dust particles come in contact with the solution. After few days, bacterial colony appears on the solution.
Cosmozoic theory
Ritcher(1864) believed that life on earth originated from spores came from other planets called panspermia.
Lesson
Origin of Life
Subject
Biology
Grade
Grade 11
Recent Notes
No recent notes.
Related Notes
No related notes.