Unit 1: The Living World Ecosystems - Practice Flashcards

Flashcards covering TOC, overfishing, terrestrial/aquatic biomes, community interactions, partitioning strategies, cycles (C, N, P, H2O), energy flow (GPP/NPP, 10% rule), thermodynamics in ecosystems, and trophic categories.

What is the Tragedy of the Commons (TOC)?

A situation where individuals acting in their own self-interest deplete a shared resource, harming the group or society.

Give an example of a TOC in practice.

Overfishing depleting fish stocks due to each fisher catching as much as possible, reducing catch for others and disrupting the ecosystem.

Name fishing methods that have contributed to fishery collapse.

Bottom trawling, drift nets, and longlining (often with high bycatch and habitat damage).

How can overfishing affect ecosystems and commerce?

It can disrupt food webs, reduce biodiversity, threaten livelihoods, and cause economic losses in fisheries and related industries.

What primary climatic factors determine terrestrial biomes?

Mean annual temperature and precipitation patterns (climate).

List some major factors that influence aquatic biomes.

Temperature, light availability with depth, nutrients, salinity, oxygen levels, and turbulence.

What are the limnetic and profundal zones?

Limnetic: open water away from shore; Profundal: deep-water zone below the limnetic, often aphotic.

What does oligotrophic mean in lakes?

Nutrient-poor and typically oxygen-rich; clear, deep lakes with low productivity.

What does eutrophic mean in lakes?

Nutrient-rich conditions often leading to algal blooms and potential oxygen depletion in deeper waters.

Explain thermal stratification in lakes.

Layering of water by temperature (epilimnion on top, hypolimnion on bottom) separating temps and chemistry.

What is fall turnover?

Autumn mixing of lake layers that redistributes nutrients and oxygen.

Define Littoral zone.

Nearshore area of a lake or sea where light reaches the bottom and vegetation grows.

Define Intertidal zone.

Area between high and low tide that is exposed during part of the day and submerged at other times.

Differentiate swamp, marsh, and wetland.

Swamp: wooded wetland; Marsh: non-woody wetland with grasses; Wetland: any saturated land with specialized vegetation.

What is a biome?

A large ecological area characterized by distinct climate, flora, and fauna (e.g., tundra, deserts, forests, oceans).

Define producer in a food web.

Autotrophs that produce organic matter from inorganic sources (primarily via photosynthesis).

Define primary, secondary, and tertiary consumers.

Primary: herbivores that eat producers; Secondary: eat primary consumers; Tertiary: eat secondary consumers.

What is an apex predator?

A top-level predator with no natural enemies within the ecosystem.

What is a detritivore?

An organism that feeds on detritus, decomposing organic matter and contributing to nutrient cycling.

State the 10% rule in energy transfer.

About 10% of energy is transferred from one trophic level to the next; the rest is lost as heat or used for life processes.

What does the direction of arrows in a food web indicate?

The direction of energy flow from lower to higher trophic levels (producer to consumer).

Define primary productivity.

The rate at which producers convert light energy into biomass (photosynthesis).

What is Net Primary Productivity (NPP)?

NPP = GPP − respiration (R); the amount of biomass available to higher trophic levels.

What is Gross Primary Productivity (GPP)?

Total amount of carbon fixed by photosynthesis in a given area and time.

Name key sources of dissolved oxygen in aquatic biomes.

Photosynthesis by aquatic plants and phytoplankton, diffusion from the atmosphere, and turbulence/aeration.

Outline the Carbon Cycle (sinks, reservoirs, sources).

Carbon moves among atmosphere, oceans, soils, vegetation, and sediments; sinks include forests and oceans; sources include respiration, decomposition, and fossil fuel combustion.

Outline the Nitrogen Cycle processes that make N2 available.

Nitrogen fixation, assimilation, nitrification, and denitrification; these processes convert N2 into usable forms for plants and animals.

Outline the Phosphorus Cycle basics and why phosphorus is limiting.

Phosphorus cycles through rocks, soils, water, and organisms; it has no atmospheric component and is often a limiting nutrient for ecosystems; both natural and synthetic (e.g., fertilizers) sources exist; excess causes eutrophication and algal blooms.

What are natural and synthetic sources of phosphorus?

Natural: weathering of rocks; Synthetic: agricultural fertilizers and industrial runoff.

What are unintended consequences of excess phosphorus and nitrogen in water bodies?

Eutrophication, algal blooms, hypoxia, and loss of aquatic biodiversity.

How does impervious surface affect the Hydrologic Cycle?

Increases runoff, decreases infiltration, reduces groundwater recharge, and disrupts natural water balance.

State the two laws of thermodynamics and their ecological relevance.

1) Energy cannot be created or destroyed; 2) Entropy increases; in ecosystems, energy is lost as heat at each transfer, limiting energy available to higher trophic levels.

How do the laws of thermodynamics appear in a food pyramid/web?

Energy input declines at higher trophic levels; arrows/links show energy flow and loss as heat and metabolic use.

How is the 2nd law of thermodynamics reflected in trophic transfers?

Only a fraction of energy is transferred to the next level; much is lost as heat and used for metabolism.