Nutrient Cycling in Terrestrial Ecosystems - Biology 20

Flashcards covering key concepts from the 'Nutrient Cycling in Terrestrial Ecosystems' lecture, including definitions, processes, and components of various nutrient cycles and ecosystem structures.

What are terrestrial ecosystems founded upon?

The productivity of primary producers.

How is energy transferred in terrestrial ecosystems?

Energy transfer comes from the amount of light energy photoautotrophs convert into organic matter, which then passes up the food chain as consumers eat producers.

What is the literal foundation of terrestrial ecosystems?

Soil.

Besides rooting substrate, what other crucial role does soil play?

It acts as a storage reservoir for nutrients plants need.

What is the top layer of soil, made of organic matter like dead leaves and feces, called?

Litter.

Which soil layer contains small rocks with partially decomposed organic matter known as humus?

Topsoil.

Which soil layer is typically dark and rich in nutrients?

Topsoil.

What is the solid rock layer that marks the end of the soil layer, often impermeable to water?

Bedrock.

How does soil quality influence an ecosystem?

It influences the diversity of the plant community and the productivity of an ecosystem.

How does a diverse plant community affect the animal community?

It dictates the diversity of the animal community by providing organic molecules for heterotrophs, creating micro-habitats, and offering more niches.

What is the coolest, moistest layer of a forest, adapted to low light conditions?

The Forest Floor.

Which forest layer contains the trunks of taller trees, shrubs, and partially shade-tolerant plants, free of wind?

Understory.

What is the forest layer where the bulk of the leaves are located, offering lots of fruit and light but potentially challenging water access?

Canopy.

How do nutrients move through ecosystems?

Through absorption in producers, consumption and assimilation in consumers, and abiotic processes.

What are some abiotic processes that help move nutrients?

The hydrologic cycle.

What term describes water moving through soil?

Percolation.

What is the land area that supplies water for a river or body of water?

Watershed.

What is runoff/overland flow?

When soil is saturated and water flows over the top and into bodies of water.

Why is nitrogen one of the most critical nutrients for plant growth?

It is an essential component of chlorophyll and required for making amino acids and proteins.

What is the largest reservoir of nitrogen, and in what form is it stored?

N2 gas in the atmosphere.

What is converting N2 gas into biologically available nitrogen called?

Nitrogen Fixation.

What is the formation of nitrites (NO2-) and nitrates (NO3-) from other nitrogen sources called?

Nitrification.

Which anaerobic process converts nitrates back into N2 gas, making it unavailable to organisms?

Denitrification.

What is the formation of ammonia (NH4+) from other nitrogen sources like urine, feces, or decomposing organic matter?

Ammonification.

What is the process called when plants and animals take in a biologically available form of nitrogen to make use of it?

Assimilation.

What is the main reservoir for phosphorus?

Sedimentary rock (no P4 is stored in the atmosphere).

What is the biologically available form of phosphorus?

Phosphate (PO43-).

Where is phosphate found in biological organisms?

In cell membranes, nucleic acids, and calcium phosphate (in bones and shells).

What is the term for when phosphorous settles out of an ecosystem and becomes stored long-term in rock formations?

Sedimentation.

What geologic process can push compacted sediments with stored phosphorus up to expose them?

Uplift or Upwelling.

What is the process where erosion or lichen releases stored phosphorus from exposed rock so that it can be absorbed by plants?

Weathering.

What concept states that the nutrient in the least supply is the one that limits an ecosystem's productivity?

Law of the Minimum.

What is the most limiting nutrient in aquatic environments?

Phosphorus.

What is eutrophication?

The contamination of water bodies with phosphorus, often leading to increased productivity and ecological changes.