The organic matter in the atmosphere, in the ocean, and on the land is very diverse. Does all of this organic matter originate from organisms?

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    $\begingroup$ Your question is at the threshold of the greatest mystery in the universe. It sort of depends on how complex a molecule needs to be to be "organic." So is there a God that created organisms, or did organisms evolve from some natural process? $\endgroup$ – MaxW Apr 16 '16 at 3:58
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    $\begingroup$ @MaxW No need for philosophy or theology in this question. $\endgroup$ – Mithoron Apr 16 '16 at 10:28

The type of molecules you are asking about are called natural products. The Earth did not coalesce from the debris of our solar system's previous sun with life on it, so clearly some conditions must have been present on prebiotic-Earth for organic molecules to form from other molecules. The Miller-Urey experiment actually demonstrates this in a very eloquent way by simulating the conditions of prebiotic-Earth. From Wikipedia:

The experiment used water ($\ce{H2O}$), methane ($\ce{CH4}$), ammonia ($\ce{NH3}$), and hydrogen ($\ce{H2}$). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a $500\: \mathrm{mL}$ flask half-full of liquid water. The liquid water in the smaller flask was heated to induce evaporation, and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate lightning in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.

This would have effectively simulated the conditions you would find on prebiotic Earth. Vast, boiling seas in an atmosphere of low molecular weight gases. Constant lightning storms in the atmosphere ionized these gases and acted provided the energy needed for chemical reactions to take place.

After a day, the solution collected at the trap had turned pink in colour. At the end of one week of continuous operation, the boiling flask was removed, and mercuric chloride was added to prevent microbial contamination. The reaction was stopped by adding barium hydroxide and sulfuric acid, and evaporated to remove impurities. Using paper chromatography, Miller identified five amino acids present in the solution: glycine, α-alanine and β-alanine were positively identified, while aspartic acid and α-aminobutyric acid (AABA) were less certain, due to the spots being faint.

In a 1996 interview, Stanley Miller recollected his lifelong experiments following his original work and stated: "Just turning on the spark in a basic pre-biotic experiment will yield 11 out of 20 amino acids."

Sure many of the more complicated natural products were produced by living organisms, but they all originate from the molecules formed in prebiotic Earth's atmosphere. Petroleum & natural gas products are only the decomposed molecules of ancient algae and zooplankton, after all.

Additionally, there is $\ce{CH4}$ in Earth's mantle has been there since Earth first formed, meaning it is totally abiogenic.

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