Question

In which of the following ways can an animal acquire a microbiome? a. Certain insects coat the casings of their eggs with bacteria. b. Newborn bees get microbes from sibling worker bees. c. Mammals, including humans, transmit important microbes as the young transit the birth canal. d. Termites use specific behaviors to transfer among themselves microbes they need to break down plant materials into food. e. All of the above are ways that animals can acquire microbiomes.

Short answer

e. All of the above are ways that animals can acquire microbiomes.

Step-by-step solution

Understand the term microbiome

A microbiome is the collection of all the microbial life that inhabit an environment, creating a sort of mini-ecosystem. In this case, the environment is the animal body.

Evaluate Statement a

Certain insects do indeed coat the casings of their eggs with bacteria. This protects the eggs and also provides the hatched larvae with an initial microbiome - confirming that this way can be used by animals to acquire a microbiome. So, statement a is true.

Evaluate Statement b

Newborn bees acquire their microbiomes from adult worker bees. The worker bees disseminate microbes within the hive that the newborn bees come into contact with, making statement b also true.

Evaluate Statement c

Mammals, including humans, do transmit important microbes as the young transit through the birth canal. This is an established route through which newborns acquire their initial microbiome, so statement c is also true.

Evaluate Statement d

Termites cooperate to transfer microbes among themselves which they need to break down plant materials into food. Therefore, this statement is also true.

Definitive Conclusion

Since all of the given statements (a through d) are true, statement e, which is 'All of the above are ways that animals can acquire microbiomes', must also be true.

Key concepts

Microbiome in Animals

The concept of a microbiome can be fascinating and complex, yet essential for understanding how animals thrive. A microbiome consists of the myriad of microscopic organisms—bacteria, viruses, fungi, and other microbes—that live in and on organisms.

Animals, from the tiniest insects to the largest mammals, have adapted to harbor specific microbiomes that play critical roles in their health, digestion, and even behavior. For instance, gut bacteria in animals aid in digesting food that the animal's own enzymes cannot breakdown. This process is evident in the case of ruminants like cows, which rely on a specialized microbiome to help them digest cellulose from the plants they eat.

As another fascinating example, some carnivorous plants such as pitcher plants have a microbiome within their digestive fluids that helps break down captured insects. This partnership between the plants and their resident microbes highlights how diverse and pervasive these microscopic communities are across animal life.

Transmission of Microbes

The spread of microorganisms from one host to another is a critical event in the establishment of a microbiome. This transmission of microbes can occur through a variety of methods, each exemplifying the incredible strategies animals use to ensure their offspring and community members are colonized by beneficial microbes.

For instance, many mammal species, including humans, pass on crucial microbes during birth which then colonize the newborn's sterile gut environment. An interesting point to add is that methods of childbirth can have a lasting impact on an individual's microbiome composition. Similarly, social insects like bees exemplify another method of microbial transmission. Worker bees spread beneficial bacteria within the hive, which the newborns then encounter, picking up a microbe collection that will assist them throughout their lives.

In the animal kingdom, the transfer of microbes is not left to chance. It is a well-orchestrated process that is vital to survival. For example, the transmission can even occur through environmental surfaces or through social behaviors such as grooming, which is common in primates.

Symbiosis in Insects and Animals

Symbiosis is a cooperative, long-term interaction between different biological species, and in the case of insects and animals, it often involves their microbiome. This relationship can be mutually beneficial (mutualism), one-sided but not harmful to the host (commensalism), or beneficial to one while detrimental to the other (parasitism).

In examples of mutualism, we see insects like the famous bobtail squid, which houses bioluminescent bacteria within a specialized organ. These bacteria help the squid by providing camouflage via counter-illumination, making the squid less visible to predators from below. The squid, in return, offers the bacteria a safe habitat and nutrients.

But symbiosis is not only about defense or predation. It's also about nutrition and survival. Termites, as mentioned in the exercise, have a symbiotic relationship with microbes in their guts. They depend on these microbes to break down cellulose from wood into simpler compounds they can absorb. This is a perfect example of how symbiosis has allowed for the evolution of unique dietary habits in the animal kingdom.