Lecture 9: Autotrophy

Question 1

What is PAR stand for ?

Answer 1

Photosynthetically active radiation

Question 2

What are 5 factors that influence how much PAR plants receive?

Answer 2

clouds
latitude (the most at the equator, 90 degrees)
Landscape features
Position of plants relative to other plants
Depth in aquatic systems

Question 3

How is the top/middle/bottom layers of a forest environment adapted to the amount of PAR they receive?

Answer 3

Many trees are adapted to both high and low PAR, middle height trees are adapted to moderate PAR, and shrubs/small plants are adapted to low PAR

Question 4

How does the availability of PAR change in aquatic systems?

Answer 4

The quality and quantity changes as it passes through the water columns of aquatic systems.
Red light is absorbed by autotrophs at the surface of the water and green is reflected (NO RED LIGHT REACHES DEEP LAYERS), and then blue light reaches the deep layers, therefore autotrophs in deep layers must be adapted to using blue PAR, and they reflect red

Question 5

What are the three variations in photosynthesis?

Answer 5

C3, C4, CAM

Question 6

What is involved in photosynthesis by a C3 plant?