Examkin

Question

Difficulty: HardGaseous Exchange and Cellular Respiration

Match each organism and its physiological state with the corresponding primary structure and mechanism utilized for gaseous exchange.

  • Adult African toad (*Sclerophrys regularis*) dormant during estivationCutaneous diffusion across moist, highly vascularized skin while pulmonary ventilation is minimized
  • Freshwater bony fish (*Tilapia zillii*) actively swimmingCountercurrent exchange of water across gill lamellae and blood within capillaries
  • Grasshopper (*Locusta migratoria*) during vigorous flightRhythmic abdominal muscle contractions forcing air through spiracles into fluid-tipped tracheoles
  • Dicotyledonous leaf (*Hibiscus*) during peak daylight photosynthesisInward diffusion of carbon dioxide through pores regulated by the turgidity of surrounding guard cells

Answer

The correct pairings are: Adult African toad during estivation matches cutaneous diffusion across moist vascularized skin; Freshwater bony fish matches countercurrent exchange across gill lamellae; Grasshopper during flight matches abdominal contractions forcing air into spiracles and tracheoles; and Dicotyledonous leaf during daylight matches inward CO2 diffusion through guard cell-regulated stomata.
Each organism utilizes specialized respiratory surfaces matched to its environment and metabolic activity: dormant adult amphibians rely on cutaneous skin diffusion; bony fish employ countercurrent flow across gill lamellae; terrestrial insects use abdominal pumping into tracheoles; and green leaves regulate stomatal diffusion via guard cell turgidity.

Step-by-Step Solution

1
Analyze the metabolic demands and structural adaptations of the estivating adult toad.
Estivation lowers metabolism and suppresses lung expansion, making cutaneous respiration across moist skin the main mode of exchange.
Amphibians switch respiratory surface reliance depending on environment and metabolic state.
2
Determine the gaseous exchange mechanism of active bony fish.
Water flowing over gill lamellae opposite to blood flow creates a countercurrent gradient ensuring efficient oxygen uptake.
Water has lower dissolved oxygen content than air, requiring a countercurrent mechanism to maximize uptake.
3
Evaluate gaseous transport in flying insects.
Insects lack hemoglobin for gas transport; active flight relies on abdominal ventilation pushing air directly through spiracles into tracheoles.
The tracheal system delivers gases directly to tissue cells without involving the circulatory fluid.
4
Identify leaf gas exchange dynamics during daylight.
High photosynthetic rate creates a CO2 concentration gradient, causing net CO2 entry through open stomata governed by guard cell turgor pressure.
Stomatal aperture changes based on osmotic water uptake by guard cells.

Key Concept

Respiratory Surface Adaptations across Diverse Taxa
Estimated Time:2m 0s
Rate this question

Topics

Gaseous Exchange and Cellular Respiration

More questions from this topic