4/5/24 - Lecture 4: Resource Acquisition

Question 1

Trade-offs

Answer 1

The relationship between the benefits of a trait in one context and its costs in another context

Question 2

Principle of allocation

Answer 2

Each organism has a limited amount of time or energy that can be used for different life processes such as obtaining food, escaping predators, etc.

Question 3

What resources do all organisms need?

Answer 3

Carbon, oxygen, and hydrogen (make up bulk of biomass)

Nitrogen, phosphorus, micro/macronutrients (make up most of an organism’s metabolic machinery)

Energy and water

Question 4

Organisms are classified into two general types based on the method they obtain energy. What are these?

Answer 4

Autotrophs and heterotrophs

Question 5

Autotrophs

Answer 5

Obtain energy from abiotic sources like inorganic carbon, nitrogen, and other essential nutrients

Question 6

Heterotrophs

Answer 6

Eat pre-formed organic molecules as food

Question 7

How can you measure the rate of photosynthesis?

Answer 7

Net photosynthesis = photosynthesis - respiration
(change in O2 in light) - (change in O2 in dark)

Basically, you take the amount of oxygen produced during photosynthesis and subtract the loss of oxygen when no photosynthesis is being performed. This is because plants respire while they photosynthesize, so you must take that into account

Question 8

Primary productivity

Answer 8

Total carbon fixed by plants per unit time

Question 9

Global net primary productivity (NPP)

Answer 9

Primary production - respiration = (rate of new biomass appearance)

Question 10

Rhizobia symbiotic relationship with legumes

Answer 10

Rhizobia provide legumes with usable nitrogen and receive amino acids in return

Question 11

Liebig’s law of the minimum

Answer 11

Production only occurs at the rate permitted by the most limiting factor (e.g. sunlight, nutrients, water)

Question 12

Why specialize?

Answer 12

Efficient at eating one of a few foods. However, the disadvantage comes if that food is in low supply

Question 13

Why generalize?

Answer 13

Can obtain energy from many sources, but may not be particularly efficient at processing them into energy

Question 14

How does prey availability affect eating patterns?

Answer 14

When there is a lot of prey available, predators prefer the prey the can get the most energy from (largest or most nutritious).

If prey availability is low, they don’t have much preference

It is important to note that there are many other factors which affect eating patterns

Question 15

Functional group

Answer 15

Sets of species showing either similar responses to the environment or similar effects on major ecosystem processes