Unit 1 & Unit 5 Ecosystems and Human Impact Study Guide

Vocabulary flashcards covering ecosystem interactions, biomes, biogeochemical cycles, primary productivity, and human resource impacts.

Parasitoid

An organism that lays its eggs inside or on a host organism, eventually leading to the host's death.

Invasive species

An exotic species that spreads rapidly and takes hold across an environment, causing harm to the native ecosystem.

Mutualism

An interaction between species that benefits both parties and increases their chances of survival.

Commensalism

A symbiotic relationship in which one organism benefits while the other is neither helped nor harmed.

Competitive exclusion principle

The principle stating that two species competing for the exact same limiting resource cannot coexist, causing one species to eventually prevail evolutionarily.

Resource partitioning

An evolutionary strategy where species divide shared resources by using different locations, times, or evolved physical traits to eliminate competition overlap.

Littoral zone

The shallow region of soil and water in lakes and ponds near the shore where emergent plants grow and the highest rate of photosynthesis occurs.

Limnetic zone

The open water layer in lakes and ponds extending as deep as sunlight can penetrate.

Profundal zone

The deep region of water in lakes beneath the limnetic zone where sunlight cannot reach.

Oligotrophic

Describes a lake with low primary productivity and low levels of phytoplankton resulting from low nutrient amounts in the water.

Eutrophic

Describes a lake with a high level of fertility and plant growth due to abundant nutrients.

Estuary

A coastal area where the fresh water of rivers mixes with salt water from the ocean.

Mangrove swamp

A swamp occurring along tropical and subtropical coastlines that contains salt-tolerant trees with submerged roots.

Coral bleaching

The death of beneficial algae living inside corals, which causes the corals to turn completely white.

Photic zone

The upper layer of ocean water that receives sufficient sunlight for photosynthesis to occur.

Chemosynthesis

A process used by deep-sea bacteria to generate chemical energy from compounds like methane and hydrogen sulfide in the absence of sunlight.

Nitrogen fixation

The process of converting unusable atmospheric nitrogen gas ($\text{N}_2$) into usable ammonia ($\text{NH}_3$) by biotic organisms.

Ammonification

The process by which decomposers break down organic nitrogen from dead organisms or waste into inorganic ammonium ($\text{NH}_4^+$).

Nitrification

The biological process converting ammonium ($\text{NH}_4^+$) into nitrites ($\text{NO}_2^-$) and then into nitrates ($\text{NO}_3^-$).

Denitrification

The conversion of nitrates ($\text{NO}_3^-$) back into nitrogen gas ($\text{N}_2$) which is re-released into the atmosphere.

Gross primary productivity (GPP)

The total amount of solar energy captured by producers in an ecosystem via photosynthesis over a given amount of time.

Net primary productivity (NPP)

The energy captured by producers minus the energy lost through cellular respiration, defined by the formula $\text{NPP} = \text{GPP} - R$.

Standing crop

The total amount of biomass present in an ecosystem at a specific point in time.

10% rule

The principle stating that only about $10\%$ of the biomass/energy available at one trophic level can be converted into usable energy at the next trophic level.

Detritivore

An organism that specializes in breaking down dead tissues and waste products into smaller organic particles.

Trophic cascade

An ecological phenomenon where the addition or removal of a top predator produces dramatic ripple effects down lower trophic levels.

Tragedy of the Commons

The degradation of shared or public resources caused by individual users acting independently according to self-interest without rules or ownership boundaries.

Externality

A benefit or cost resulting from the creation or consumption of a good or service that is not reflected in its financial purchase price.

Fishery collapse

The decline of a commercially harvestable fish population within an ecological region by $90\%$ or more.

Bycatch

The unintentional capture of non-target marine species, such as sea turtles and sharks, during commercial fishing.

Sustainable Fisheries Act of 1996

US legislation passed to protect critical marine habitats and restore overfished populations by establishing total allowable catch limits and fishing season restrictions.