The evolution of cuticle presented plants with a challenge that threatened their ability to live on land. Describe this challenge, and explain why stomata represent a solution. Compare and contrast stomata with the pores found in liverworts.

Verified step by step guidance

1. Identify the challenge: The evolution of the cuticle, a waxy layer on the surface of plants, helped prevent water loss but also restricted gas exchange, which is essential for photosynthesis and respiration.
2. Explain the solution: Stomata are specialized structures that can open and close to regulate gas exchange. When open, they allow carbon dioxide to enter for photosynthesis and oxygen and water vapor to exit.
3. Describe stomata structure: Stomata are composed of two guard cells that change shape to open or close the pore. This regulation helps maintain water balance while allowing necessary gas exchange.
4. Compare with liverwort pores: Liverworts, which are non-vascular plants, have simple pores that are always open, providing no control over water loss, unlike the regulated openings of stomata in more advanced plants.
5. Contrast effectiveness: Stomata provide an evolutionary advantage by allowing plants to inhabit a wider range of environments due to their ability to control water loss and still facilitate gas exchange, unlike the constant open state of liverwort pores.

Key Concepts

Cuticle and Water Retention

The cuticle is a waxy layer that covers the surfaces of terrestrial plants, preventing water loss. While it is essential for reducing desiccation, it also poses a challenge for gas exchange, as it limits the diffusion of carbon dioxide and oxygen necessary for photosynthesis and respiration.

Stomata Functionality

Stomata are specialized pores found on the surfaces of leaves that facilitate gas exchange. They can open and close in response to environmental conditions, allowing plants to balance water retention with the intake of carbon dioxide, thus providing an effective solution to the challenges posed by the cuticle.

Comparison with Liverwort Pores

Liverworts, which are non-vascular plants, have simpler pores that do not function like stomata. These pores remain open and lack the ability to regulate gas exchange actively, making liverworts more susceptible to water loss compared to vascular plants with stomata, which can control their internal environment more effectively.