Question

The large intestine of humans is populated by a complex community of benign microorganisms (not harmful) which compete for nutrients and may prevent pathogenic (harmful) microorganisms from becoming established. Which term would best describe this? a. competitive exclusion b. selective pressure c. succession d. environmental resistance

Short answer

a. competitive exclusion

Step-by-step solution

Understand the Scenario

The scenario describes a community of benign microorganisms in the human large intestine that compete for nutrients and prevent harmful microorganisms from establishing.

Define Each Term

a. Competitive exclusion: A principle that states when two species compete for the same resources, one will outcompete the other.b. Selective pressure: Environmental factors that favor certain traits over others, guiding evolution.c. Succession: A process by which the structure of a biological community evolves over time.d. Environmental resistance: Factors that limit the growth of populations and keep them in check.

Identify the Most Appropriate Term

The best term to describe the microorganisms competing for nutrients and preventing harmful ones from establishing is 'competitive exclusion'.

Key concepts

large intestine microbiome

The large intestine, also known as the colon, is home to an intricate and diverse community of microorganisms. This community is known as the large intestine microbiome. These microorganisms play a crucial role in our digestion and overall health. Within this microbiome, billions of bacteria, fungi, and viruses coexist.
One key function of the large intestine microbiome is to break down complex carbohydrates that our body cannot digest on its own. This results in the production of essential vitamins, such as vitamin K and some B vitamins. Moreover, the microbiome helps maintain the health of the intestine by producing substances that inhibit the growth of harmful microorganisms. This contributes to the body's immune defense system.
Another important role of the microbiome is regulating the immune system. The interaction between the microbiome and the immune cells helps in training the immune system to distinguish between harmless and harmful entities. This careful balance ensures that the body does not overreact to benign microorganisms while still being able to fend off pathogens.
In summary, the large intestine microbiome is a vital component of our digestive and immune systems, fostering a balanced environment that supports health and well-being.

benign microorganisms

Benign microorganisms are those that do not cause harm to their host. In the context of the large intestine, these microorganisms include various bacteria that are beneficial or neutral to human health. An example of benign microorganisms in the large intestine is the Bifidobacterium species.
These microorganisms compete for nutrients in the gut, a process known as competitive exclusion. By thriving in the large intestine, they create an environment less favorable for pathogenic microorganisms. This natural competition helps to prevent infections and maintain gut health.
Benign microorganisms also contribute to the synthesis of essential nutrients. For example, they help produce short-chain fatty acids through the fermentation of dietary fibers. These fatty acids serve as an energy source for colon cells and aid in keeping the gut lining healthy.
Therefore, benign microorganisms support the digestive process, enhance immune defense, and protect against diseases by outcompeting harmful pathogens.

pathogenic microorganisms

Pathogenic microorganisms are those that can cause disease in their host. In the human large intestine, these can include bacteria such as Salmonella, Escherichia coli (certain strains), and Clostridium difficile.
These pathogens can disrupt the normal functioning of the gut and lead to illnesses ranging from mild gastrointestinal discomfort to severe, life-threatening conditions. Pathogenic microorganisms achieve this by producing toxins, invading host tissues, or eliciting strong immune responses that damage host cells.
The presence of a healthy population of benign microorganisms in the large intestine helps to prevent the establishment of pathogenic microbes through competitive exclusion. The benign microorganisms occupy available niches and resources, depriving pathogens of the opportunity to thrive.
In addition to competition, the benign microorganisms can produce substances, such as bacteriocins, that specifically inhibit the growth of pathogens. This protective mechanism further strengthens the body's defense line within the gut.
By understanding the balance between benign and pathogenic microorganisms, we can appreciate how maintaining a healthy microbiome is essential for preventing infections and supporting overall health.