Ecology, Ecosystem Dynamics, and Biogeochemical Cycles

Comprehensive vocabulary flashcards covering ecological organization, trophic relationships, energy flow, human impacts, and the nitrogen, carbon, and water cycles.

Ecology

The scientific study of the interactions between living organisms and their environment, including both living (biotic) and non-living (abiotic) components.

Habitat

The place or specific environment where an organism naturally lives and grows, providing its three survival essentials: food, shelter, and a breeding site.

Biotic Factors

The living components of an ecosystem that affect other organisms, such as predators, prey, competitors, diseases, and food sources.

Abiotic Factors

The non-living, physical or chemical components of an ecosystem that affect living organisms, such as temperature, light intensity, pH, moisture, and oxygen levels.

Terrestrial Ecosystem

A land-based community of organisms interacting with their physical environment, such as tropical rainforests, deserts, tundras, and grasslands.

Aquatic Ecosystem

A water-based community of organisms interacting with their environment, categorized into freshwater (rivers, lakes, ponds) and marine (oceans, coral reefs, estuaries).

Man-Made Ecosystem (Artificial Ecosystem)

An ecosystem created, managed, and maintained by humans to meet specific needs, often requiring human intervention to survive (such as farmlands, fish farms, urban parks, and aquariums).

Deforestation

The permanent removal or clearing of forests and woodlands to make land available for other uses, such as agriculture, urban expansion, or mining.

Individual

A single, separate, distinct living organism belonging to a particular species.

Population

All the members of the same species living and interacting in a particular area at the same time.

Community

All of the populations of different living organisms interacting together in a specific area, forming the biotic environment.

Ecosystem

A self-contained unit consisting of all the living organisms (community) and the non-living (abiotic) factors interacting together in a particular part of the environment.

Biome

A group of similar ecosystems sharing a comparable climate and vegetation type globally.

Biosphere

All the regions of the Earth where living organisms and life exist, consisting of all ecosystems connected to each other across the entire planet.

Nested Hierarchy

The organization of the biological world into levels that range from the smallest, most specific unit to the largest, broadest system.

Competition

A community relationship where organisms of different species struggle for the same limited resources (such as food, water, light, or space) in the same area, resulting in neither species benefiting.

Predation

A community relationship in which organisms of one species (the predator) kill and consume tissues of organisms of another species (the prey) to stay alive.

Symbiosis

A close relationship between two organisms of different species in which at least one of the organisms benefits.

Mutualism

A symbiotic relationship in which individuals from both interacting species benefit from each other.

Commensalism

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

Parasitism

A symbiotic relationship in which one species benefits while the other species suffers or is harmed.

Autotrophs

Organisms that make their own organic molecules (food) from inorganic sources by directly using energy from the Sun or from chemical bonds.

Photoautotrophs

Autotrophs that use energy from sunlight to synthesize organic compounds via photosynthesis, such as plants, algae, and some bacteria.

Chemoautotrophs

Autotrophs that use energy derived from chemical bonds to synthesize organic compounds via chemosynthesis.

Heterotrophs

Organisms that cannot produce their own food and must obtain energy and nutrients by consuming other living things.

Herbivores

Heterotrophs that act as primary consumers by directly feeding on producers such as plants or algae.

Carnivores

Heterotrophs that obtain energy and nutrients exclusively by feeding on other animals through hunting or scavenging, functioning as secondary or tertiary consumers.

Omnivores

Consumers with a varied diet that feed on both plant and animal matter, enabling them to occupy multiple trophic levels depending on available food sources.

Decomposers

Heterotrophic organisms (such as fungi and bacteria) that break down and feed on the remains of dead organisms and waste like feces, releasing simple organic molecules back into the environment.

Detritivores

A category of decomposers composed of animals (such as earthworms and crabs) that ingest dead organic matter and break it down internally.

Saprotrophs

A category of decomposers that break down dead matter externally by secreting digestive juices outside the body and subsequently absorbing nutrients.

Food Chain

A linear sequence of organisms through which nutrients and energy pass as one organism eats another.

Food Web

A network of interconnected food chains that displays all feeding relationships and energy pathways between organisms across multiple trophic levels in an ecosystem.

Food Pyramid

An ecological model that illustrates the quantitative loss of energy as it transfers from one trophic level to the next.

Photosynthesis

The biological process in chloroplasts converting light energy from the sun into chemical energy: $6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$.

Cellular Respiration

The metabolic process in mitochondria by which cells break down glucose and other organic molecules in the presence of oxygen to release usable chemical energy: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}$.

Trophic Energy Transfer Efficiency

The principle that $80\%$ to $90\%$ of energy stored in a food organism is used for chemical reactions, cellular respiration, reproduction, waste, movement, and lost as heat, leaving only a fraction available to the next trophic level.

One-Way Energy Flow

The thermodynamic flow where energy enters an ecosystem from the Sun, passes through organisms, and is permanently converted into heat that escapes into the atmosphere and cannot be reused.

Matter Recycling

The conservation and movement of physical atoms in a closed loop between living organisms and the physical environment, ensuring resources like carbon, nitrogen, and water are not destroyed or lost.

Nitrogen Fixation

The conversion of atmospheric nitrogen gas ($N_2$) into usable forms like ammonia or nitrates by nitrogen-fixing bacteria (in soil and legume root nodules) or lightning.

Nitrification

The two-step aerobic process where soil nitrifying bacteria convert ammonia and ammonium ions into nitrites, and then into nitrates ($NO_3^-$) that plants can absorb.

Assimilation (Nitrogen Cycle)

The process by which plants absorb nitrates through their roots to synthesize proteins, DNA, and vitamins, which are subsequently passed to animals through feeding.

Ammonification

The process where decomposers break down nitrogenous waste and dead organic material, returning nitrogen to the soil in the form of ammonia.

Denitrification

The anaerobic process where denitrifying bacteria in waterlogged, low-oxygen soils obtain energy by converting soil nitrates ($NO_3^-$) back into atmospheric nitrogen gas ($N_2$).

Fossilization (Carbon Cycle)

The process occurring over millions of years where dead plants and animals subject to significant pressure in the absence of decomposers are converted into fossil fuels (coal and oil).

Combustion (Carbon Cycle)

The burning of fossil fuels (coal, oil, gas) that rapidly combines stored carbon with oxygen and releases carbon dioxide ($CO_2$) back into the atmosphere.

Water Cycle

A closed system driven by the Sun's energy and gravity where a constant amount of water circulates via evaporation, transpiration, condensation, precipitation, and runoff.

Greenhouse Effect

The trapping of infrared radiation by increasing concentrations of atmospheric gases like carbon dioxide ($CO_2$) and methane ($CH_4$), intensifying global warming and extreme weather events.

Acid Rain Precursors

Sulfur dioxide and nitrogen oxides released during fossil fuel combustion that directly react in the atmosphere to produce acid rain.

Poaching

The illegal hunting and killing of animal species that harms vital populations, disrupts food chains and feeding mechanisms, and degrades ecosystem stability.

Protected Areas

Designated geographical zones that provide secure habitats free from hunting and disturbance, protecting endangered species and supporting biodiversity.