Question

In both transpiration and evaporation, water is lost in the form of vapour yet they differ, because (a) Both transpiration and cvaporation are similar but the rate of water loss differs. (b) Frequency of water loss is different in both of them. (c) Transpiration is a physical process and evaporation is a physiological process. (d) Transpiration is a physiological process and cvaporation is a physical process.

Short answer

The correct answer is (d) Transpiration is a physiological process and evaporation is a physical process.

Step-by-step solution

Understand the nature of processes

First, let's define the two types of processes we're dealing with: Physical and physiological. Physical processes are natural phenomena or mechanisms that do not involve the living biological systems. They are guided by the laws of physics and chemistry. On the other hand, physiological processes are the processes and functions carried out within living organisms, including all bodily activities such as heartbeat, breathing, cell division, neural function etc. Basically, physiological processes pertain to organ systems and how they work together to make life possible.

Categorizing Transpiration & Evaporation

With that information, we can categorize transpiration and evaporation. Transpiration is a physiological process because it involves the functions of a living organism, in this case, a plant. The plant “chooses” to transpire (in a manner of speaking), and it is a process that aids in water and nutrient transport, cooling, and gas exchange. Whereas, evaporation is a physical process because it does not involve any biological mechanisms. It occurs on the surface of liquid and changes into the gas phase without becoming saturated.

Choose the correct statement

Based on the categorization, the correct option is (d) Transpiration is a physiological process and evaporation is a physical process. The other options do not correctly describe the difference between the processes of transpiration and evaporation.

Key concepts

Physiological Processes in Plants

Plants are not passive entities; they are complex organisms that engage in a myriad of physiological processes vital for their survival and growth. One of the core physiological activities is transpiration, the process of water movement through a plant and its evaporation from aerial parts, like leaves, stems and flowers. This is not a random occurrence, but a controlled activity that plays multiple roles, including cooling the plant surface, maintaining the flow of nutrients, and helping to draw water from the roots to the upper parts of the plant.

Physiological processes in plants are regulated by both internal and external stimuli. For example, the opening and closing of stomata, small pores found on the underside of leaves, control transpiration. These openings respond to environmental cues such as light intensity, humidity, and the concentration of carbon dioxide, reflecting how interconnected physiological processes are with the plant's immediate surroundings. Similarly, physiological responses can be observed in other processes like photosynthesis and cellular respiration, both imperative for plant energy management and metabolism.

Physical Processes in Nature

Differing from the deliberate activities of living organisms like plants, physical processes in nature encompass a wide variety of mechanisms that occur in the environment. Evaporation is a quintessential example of a physical process, which involves the transformation of water from liquid to gas. This process can happen on any open body of water such as lakes, oceans, and even puddles after a rainstorm. It is governed by factors including temperature, air pressure, and solar radiation, and doesn't require any biological input.

In contrast to the selective behavior of transpiration in plants, evaporation is indiscriminate and constant, as long as conditions are favorable. It's part of the water cycle, fundamental for weather patterns and climate systems, and doesn't distinguish between water molecules from a lake or sweat from a runner's brow. This non-biological process is essential to earth’s hydrology, ensuring that water continues to circulate through our environment.

Plant Water Transport

The movement of water within plant systems is an intriguing aspect of botany. Root systems absorb water from the soil, which is then transported throughout the plant via specialized tissues known as xylem. This process is propelled by capillary action, root pressure, and transpiration pull. Transpiration plays a pivotal role in this water transport system; the loss of water vapor from leaves creates a negative pressure (a suction force) in the xylem that pulls water upwards from the roots. This upward movement against gravity is a fascinating display of how plants manage their fluid dynamics.

Through this seamless integration of physiological processes, plants can efficiently distribute not just water but also dissolved minerals and nutrients critical for their physiological functions. Moreover, this process illustrates the delicacy of plant life, as water transport must be carefully balanced to avoid either dehydration or over-saturation, both of which can be detrimental to the plant's health.