A body is said to live only if they can show the characteristics of life are: need for nutrition, move, breathe, grow and develop, conduct of excretion / metabolism remains expenditures, breed, are sensitive to stimuli (iritabilita), coordination, and adaptation.
Origin of Life
How did the first living creature was born remains a mystery yet to be revealed by scientists. In general theory of the origin of life there are two, that is abiogenesis (origin of living things from inanimate objects) and biogenesis (brasal living things from living things, too.)
1. Abiogenesis theory
Leaders understand this is a nation of Greece, which Aristotle (394-322 BC). His theory says that the first living creatures that inhabit this earth is derived from inanimate objects. The first emergence of living things that happen spontaneously because of the lifestyle. Therefore referred to also understand understand abiogenesis spontaneous generatio. It lasted long enough to understand, that ever since ancient Greece (hundreds of years BC) until the mid 17th century.
In the mid 17th century understood this as if strengthened by Antonie van Leeuweunhoek, a Dutch national. He found a simple microscope that can be used to view the larva (living things) a very small drop of water depth in the straw. This has seemed to strengthen understanding abiogenesis.
2. Theory of Biogenesis
After last long enough, the notion began to doubt abiogenesis. Some experts later revealed understand biogenesis. Some experts who understand the biogenesis revealed, among others:
a. Francesco Redi (Italian, 1626-1697)
Redi against abiogenesis theory by conducting an experiment using a jar and meat. 1 jar filled with meat that is closed tightly. 2 jars filled with meat and covered with cloth netting. 3 diiisi meat and jar is opened. The third jar was left a few days. From the results of these experiments he concluded as follows: The larvae (the life) did not come from rotting flesh but derived from flies that can enter into the tube and lay eggs on meat keratin.
b. Lazzaro Spallanzani (Italian, 1729-1799)
Spallanzani oppose John Needham (adherents understand abiogenesis), thinks that life happens to the water caused by a warming broth that is not perfect. Conclusion spallanzani experiment is: there is life on the open tube from the air, in a closed tube there is no life, it proves that life is not from the broth.
c. Louis Pasteur (French, 1822-1895)
Louis Pasteur performed experiments that refine Spalanzani experiment. Mlakukan Pasteur experiments using goose neck gourd cap, intended to prove that there are microorganisms in the air along with dust. Experiments are as follows:
- Microorganisms that grew not from an inanimate object (liquid), but from microorganisms contained in air
- The body of microorganisms found in the air along with dust
From this experiment, the theory of abiogenesis are servants.
Pasteur's famous motto "vivum Omne ex ovo, ova Omne ex vivo", which comprises: life comes from eggs and eggs produced living creatures, living things are now derived from previously living things, living things come from living things as well.
In addition to the above two theories, there is again a few theories about the origins of life. Some scientists developed the theory, among others:
A. theory of special creations, which claims that life was created by a supernatural agent (unseen) at a special time
B. Kosmozoan theory, which states that life on this planet come from anywhere
C. Biochemical evolution theory, which states that life comes under the laws of physics, chemistry and biology
D. Steady state theory, stating that life does not come proposals.
Some scientists who proved the theory of chemical evolution, among others, Harold Urey, Stanley Miller, and Alexander Oparin
- Harold Urey's theory, according to the first living substance has a structure resembling a virus today. Substance life experience of the development to become various kinds of living beings. Urey believes that life occurs first in the air (atmosphere). At a certain moment in the history of the rich atmosphere formed molecules CH4, NH3, H2, H2O. because of the jump due to lightning and power cosmic rays occurs that enables the amino acid occurs life.
- Experiment Stanley Miller, Stanley Miller was a student of Harold Urey was also attracted to the problem of the origin of life. He performed an experiment to test the hypothesis Harold Urey. From the results of Miller's experiments may provide clues that the units in the complex system of life such as lipids, carbohydrates, amino acids, proteins, nucleotides and others can be formed in abiotic conditions.
- Theory of Evolution Biology Oparin, he believes that the first life occurred in the coastal basin with embankment materials and organic compounds from the ocean. Heaps of organic compounds is called the primordial soup or primordial soup.
Although many of the instructions given, the origin of life remains a mystery. If this mystery is revealed, is it possible that humans will become creators can even create life?
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