Question

Read the given statements and select the correct option, Statement \(1:\) Mammals can eat while breathing. Statement \(2:\) Mammals have negative-pressure breathing. (a) Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1 . (b) Both statements 1 and 2 are correct but statement 2 is not the correct explanation of statement 1 . (c) Statement 1 is correct and statement 2 is incorrect. (d) Both statements 1 and 2 are incorrect.

Short answer

Both statements are correct, but statement 2 is not the correct explanation of statement 1. The correct option is (b).

Step-by-step solution

Understanding Statement 1

Analyze if mammals can eat while breathing. Mammals have a specialized structure called the secondary palate that separates the nasal passage from the oral cavity, allowing them to breathe while eating.

Understanding Statement 2

Consider if mammals have negative-pressure breathing. Mammals do have negative-pressure breathing; they expand their chest cavity through muscular action, decreasing pressure in the lungs, which causes air to flow in for respiration.

Correlating Both Statements

Determine whether statement 2 is a correct explanation of statement 1. Negative-pressure breathing is a mechanism of breathing and not directly responsible for the ability to eat while breathing; the secondary palate plays a key role in allowing concurrent eating and breathing.

Choosing the Correct Option

Based on the analysis, both statements 1 and 2 are correct, but statement 2 is not the correct explanation of statement 1, which leads us to option (b).

Key concepts

Negative-pressure Breathing

Negative-pressure breathing is a unique respiratory mechanism observed in mammals, including humans, which facilitates the intake of air into the lungs. Unlike fish with their buccal pumping or birds with their flow-through system, mammals use muscular expansion to create a lower pressure inside their lung cavities compared to the outside environment, effectively creating a vacuum.

When a mammal inhales, its diaphragm—the primary muscle involved in breathing—contracts and moves downward. Simultaneously, the muscles between the ribs, known as the intercostal muscles, expand the rib cage. This double action increases the volume of the thoracic cavity, where the lungs are housed. Since the pressure inside the thoracic cavity decreases, air rushes in through the nose or mouth to equalize the pressure.

This type of breathing is highly efficient and allows mammals to have a more controlled and deeper respiration, which is essential for high metabolism and endothermy—attributes that are characteristic of mammals. This process is reversed during exhalation, where the diaphragm and intercostal muscles relax, resulting in an increase in pressure that expels air out of the lungs.

Secondary Palate

The secondary palate is an anatomical feature that has significantly contributed to the adaptability and success of mammals. It is a bony or cartilaginous structure which effectively separates the nasal passages from the oral cavity. This separation serves a crucial purpose: it allows mammals to chew and process food while simultaneously breathing through their noses.

For non-mammals, the oral cavity is often involved in both eating and respiration, which can be limiting. Mammals, however, thanks to the secondary palate, can continue respiration without interruption, even when the mouth is full or engaged in food processing. This not only facilitates sustained physical activity but also supports the high energy demands by allowing for more consistent oxygen intake.

The development of the secondary palate is particularly evident during embryonic development and becomes a defining characteristic of mammals, setting them apart from their reptilian ancestors and other vertebrates. It is a key factor in enabling the behavior of concurrent eating and breathing and provides a competitive edge in the animal kingdom.

Concurrent Eating and Breathing in Mammals

The ability to eat and breathe concurrently is a distinctive characteristic of mammals that has considerable implications for their survival and efficiency. This capability is largely attributed to the evolutionary development of the secondary palate, which allows mammals to handle food in their mouths while maintaining a clear airway for respiration.

Such an anatomical adaptation permits mammals to feed their young with milk from mammary glands—another distinguishing feature of the group—without the need for the offspring to detach from the nipple to breathe. Moreover, adult mammals can graze or hunt more effectively since they do not need to stop breathing while manipulating and chewing food.

The concurrent eating and breathing adaptability provides mammals with the ability to maintain a steady supply of oxygen, which is crucial during prolonged periods of feeding. This adaptation underscores the synergistic evolution of various mammalian features, such as endothermy and active lifestyles, which require high oxygen levels and energy intake.

Exercise Improvement Advice

When interpreting the association between concurrent eating and breathing and negative-pressure breathing, it's crucial to understand that while they are both integral to mammalian survival, they are functionally independent mechanisms. The negative-pressure breathing facilitates air intake, while the secondary palate enables the dual-tasking ability of concurrent eating and breathing. Clarifying this distinction is key to a comprehensive understanding of mammalian physiology.