plant adaptation to environment

Question 1

In what environments would you expect C4 plants to be rare or absent?

Answer 1

Cold environments with low temperatures during the growing season

C4 plants thrive in warm conditions and are less competitive in cooler climates.

Question 2

What is the most typical habitat for CAM plants?

Answer 2

Drier areas, like deserts where water is scarce

CAM plants adapt to arid conditions by opening their stomata at night.

Question 3

What morphological feature is associated with CAM photosynthesis?

Answer 3

Fleshy (succulent) leaves and/or stems with large vacuoles

These adaptations help CAM plants store water and malate.

Question 4

Give an example of the tradeoff between traits that enhance fast resource uptake and tolerance to low resource levels for light.

Answer 4

Sun-adapted leaves are thicker with higher stomatal density; shade-adapted leaves are thinner with higher chlorophyll per biomass

This demonstrates the balance between fast growth in high light and efficiency in low light.

Question 5

Give an example of the tradeoff between traits that enhance fast resource uptake and tolerance to low resource levels for water.

Answer 5

CAM plants exhibit high water-use efficiency by opening stomata at night; this comes with slower growth due to limited storage capacity for malate

The tradeoff reflects the balance between water conservation and growth rate.

Question 6

What are the two principal strategies that land plants follow to deal with water scarcity?

Answer 6

• Water conservation - minimizing water loss
• Water access - accessing water at greater depth

These strategies help plants survive in arid conditions.

Question 7

How does the ratio of C3:C4 plants change from North to South in the American Prairie?

Answer 7

The proportion of C4 plants increases, peaking in summer; C4 photosynthesis is favored by higher temperatures

This shift indicates the adaptability of plant types to climatic conditions.

Question 8

What does the Beer-Lambert law say?

Answer 8

For every unit of LAI traversed, a fixed fraction of light is intercepted

This law is fundamental in understanding light absorption in plant canopies.

Question 9

What are the differences between shade and sun adapted leaves?

Answer 9

• Shade-adapted leaves tend to be larger with thinner structures
• Sun-adapted leaves are typically smaller, thicker, and have more waxy cuticles

These differences reflect adaptations to light availability.

Question 10

In what way do these adaptations help leaves function in high and low light environments?

Answer 10

• Shade-adapted leaves efficiently capture light in low-light environments
• Sun-adapted leaves maximize photosynthesis in high-light environments

This illustrates the ecological strategies of different plant types.

Question 11

What is an example of phenotypic plasticity mediated by the phytochrome system?

Answer 11

Shade avoidance through etiolation in response to low red:far-red light ratios

This mechanism allows plants to adapt to competition for light.