Ecology - Primary Production & Energy Flow

A set of practice flashcards covering primary productivity, energy flow, and trophic dynamics based on the provided lecture notes.

What units are used to express primary productivity (PP)?

kcal per square meter per year (kcal/m^2/yr).

How can primary productivity be described in terms of photosynthesis?

The rate at which solar energy is converted into organic compounds via photosynthesis over a unit of time.

How else can PP be interpreted?

The amount of plant growth in an area over a given period of time.

What does GPP stand for and what does it represent?

Gross Primary Productivity; the total solar energy captured and converted to energy (glucose) through photosynthesis.

What does RL stand for and what does it represent?

Respiration loss; energy used by plants for respiration (movement, internal transport, etc.).

What does NPP stand for and how is it calculated?

Net Primary Productivity; energy left after respiration, available to consumers; NPP = GPP − RL.

In an analogy, what do GPP and NPP represent?

GPP is the total paycheck earned by a plant; NPP is the paycheck remaining after taxes (respiration).

What percent of solar energy striking producers is captured by photosynthesis (GPP)?

About 1%.

What percent of solar energy is reflected or passes through producers without absorption?

About 99%.

What percent of GPP is lost to respiration?

About 60%.

What percent of GPP supports growth and reproduction (NPP)?

About 40%.

What factors contribute to high NPP?

Water availability, higher temperature, and nutrient availability.

True or False: A more productive biome can support a wider diversity of animal life.

True.

Name three biomes mentioned as trends in productivity.

Desert, tundra, open ocean.

What does the First Law of Thermodynamics state?

Energy cannot be created or destroyed; it only changes form.

What do biogeochemical cycles demonstrate?

Conservation of matter (C, N, H2O, P).

Give an example of energy transfer in a food interaction.

When a rabbit eats a leaf, the energy from the leaf is transferred to the rabbit and stored as body tissue.

What does the Second Law of Thermodynamics imply for energy transformations?

They are never perfectly efficient; some energy is lost as heat, increasing entropy.

What is the 10% rule in trophic pyramids?

Approximately 10% of energy from one trophic level is transferred to the next; ~90% is used or lost as heat.

Does the 10% rule apply to biomass as well?

Yes; about 10% of biomass is transferred to the next trophic level.

If producer biomass is 1000 kg, what is the approximate biomass of the first consumer level?

About 100 kg (10%).

If the first consumer level has 100 kg of biomass, what is the approximate biomass of the next level?

About 10 kg.

If the second consumer level has 10 kg, what is the approximate biomass of the next level?

About 1 kg.