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#chemoautotrophs

2 public questions tagged with this topic.

Chemogeny & biogeny

Chemoautotrophs evolved to overcome

Continued consumption of finite prebiotic organics by chemoheterotrophs would exhaust hot dilute soup, creating selective pressure for alternative carbon acquisition. Chemoautotrophs developed pathways to fix carbon dioxide using inorganic electron donors like H2S, Fe2+ or H2, independent of organic supply. This innovation allowed colonization of environments lacking organics and preceded photoautotrophy. The transition illustrates metabolic evolution driven by resource limitation. Hence Depletion of organic matter represents adaptive response to diminishing organic resources. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.

Ref: Alberts et al., Molecular Biology of the Cell, 6th ed., Chapter 1: Origin of Life.

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Ecosystem Ecology & PRODUCTIVITY

Chemoautotrophs are mainly responsible for primary productivity in:

At deep-sea hydrothermal vents sunlight is absent, but reduced chemicals such as hydrogen sulfide and hydrogen provide usable energy. Chemolithoautotrophic bacteria and archaea oxidize these compounds and use the released energy to fix inorganic carbon, supporting food webs independent of photosynthesis. Primary production supports heterotrophic food webs by converting external energy into chemical energy stored in organic matter. The fate of that energy depends on maintenance respiration, growth, consumption, death, and decomposition. Carbon can be tracked as gross fixation, producer biomass increment, or whole-system accumulation, and each quantity has a different equation. Because respiration irreversibly dissipates usable energy as heat, energy moves directionally through trophic levels even though nutrients released by decomposers may cycle repeatedly. In this context, the keyed term, Deep-sea vents, identifies the relevant mechanism or quantitative relationship and links the observed pattern to its underlying ecological cause. The distinction is testable by measuring changes in organisms, resources, or process rates through time rather than relying on the label alone.

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 17

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