Problem 22 - Objective Biology for NEET

Question

Following are present in gut of cows and buffaloes and is responsible for the production of methane from the dung of these animals (a) Methanogen (b) Thermoacidophiles (c) Halophils (d) All of these

Step-by-Step Solution

Answer

The microbes responsible for the production of methane from the dung of cows and buffaloes is (a) Methanogen.

Step 1: Identify the Roles of the Microbes

Methanogenes are microbes that produce methane by decomposing organic matter, in this case, dung. Thermoacidophiles are microbes that live in hot and acidic environments, not related to this process. Halophiles are microbes that thrive in very salty environments, also unrelated to this process.

Step 2: Choose the Correct Answer

Among the given options, Methanogens are the only class of microbes associated with the production of methane from the dung of cows and buffaloes. Thus, the correct answer is (a) Methanogen.

Key Concepts

Microbes in Ruminant Gut

Ruminants like cows and buffaloes have a unique digestive system that relies heavily on a diverse microbial population within their gut, specifically in the rumen, which is the largest of the four compartments of their stomach. Here, a symbiotic relationship exists between the ruminant and the microorganisms, including bacteria, protozoa, fungi, and archaea.

Methanogens, a type of archaea, are particularly significant as they are responsible for a key process known as enteric fermentation. During this process, methanogens decompose complex organic substances like cellulose and other carbohydrates that animals cannot digest on their own. They convert these substances into simpler compounds, releasing methane as a byproduct. This digestive capability allows ruminants to eat a variety of plant materials. Without these microbes, ruminants wouldn't be able to access the nutrients locked in fibrous plant matter.

While methanogens are critical for the breakdown of feed, they are not the only inhabitants of the gut. Other microbes contribute to the breakdown of different food components, synthesizing essential vitamins and nutrients, and preventing harmful bacteria from establishing within the gut environment. This intricate microbial ecosystem is finely balanced and crucial for the health and nutrition of ruminant animals.

Methane Production in Animals

Methane production in animals, particularly ruminants, occurs through the activity of methanogens during digestion. These microorganisms are part of the microbiome in the rumen and play a fundamental role in converting hydrogen and carbon dioxide into methane in an anaerobic process called methanogenesis. This is part of a larger cycle where the removal of hydrogen allows other microbes to continue fermenting the ingested plant material.

The methane produced is mostly belched out by the animal; a smaller portion is emitted through flatulence or in manure. Although methane is a natural byproduct of digestion for these animals, it has significant implications for the environment, notably as a potent greenhouse gas. Understanding the biological processes that lead to methane creation in animals can inform strategies to reduce emissions, such as dietary adjustments, feed supplements, and selective breeding practices.

Researchers are actively studying ways to alter the microbial composition or activity within the ruminant gut to decrease methane production. These methods could maintain animal health and productivity while mitigating the environmental impact of livestock farming.

Biological Decomposition

Biological decomposition is a process carried out by decomposers, organisms that break down dead or decaying organic matter. This matter includes plant residues, dead animals, and waste products such as dung. In the context of ruminant digestion, biological decomposition is performed by the gut microbiome, transforming complex organic feed into simpler, absorbable nutrients.

Methanogens are a key group involved in this decomposition process. They specialize in breaking down organic molecules under anaerobic (oxygen-free) conditions, which predominantly occur in environments like the guts of ruminants or anaerobic sludge digesters. The end product of their metabolic activity is methane, which is then released into the atmosphere when the animal belches.

The process of biological decomposition not only recycles nutrients to be used by plants and other organisms but also contributes to soil fertility by creating substances like humus. While this process is critical for ecosystem health and nutrient cycling, it also has the side effect of releasing methane, a greenhouse gas, highlighting the importance of finding ways to balance agricultural productivity with environmental sustainability.