Ecosystems and Energy Flow

Flashcards covering ecosystem dynamics, energy flow, trophic levels, productivity, and biogeochemical cycles based on the lecture transcript.

Ecosystem

A community of living organisms and their interactions with their abiotic (nonliving) environment.

Abiotic

The nonliving components of an environment.

Equilibrium

A steady state of an ecosystem where organisms are in balance with their environment and each other.

Resistance

The ability of an ecosystem to remain at equilibrium in spite of disturbances.

Resilience

The speed at which an ecosystem recovers equilibrium after being disturbed.

Food chain

A linear sequence of organisms through which nutrients and energy pass, including primary producers, primary consumers, and higher-level consumers.

Trophic level

The specific position an organism occupies in a food chain or food web.

Primary producers

Organisms at the bottom of the food chain that acquire energy through photosynthesis or chemosynthesis.

Primary consumers

Herbivores that consume the primary producers.

Secondary consumers

Carnivores that eat the primary consumers.

Tertiary consumers

Carnivores that eat other carnivores.

Apex consumers

Organisms at the top of the food chain.

Photoautotrophs

Organisms such as plants, algae, and photosynthetic bacteria that harness solar energy and convert it to chemical energy in the form of $ATP$.

Chemoautotrophs

Primarily bacteria found in ecosystems without sunlight that use inorganic molecules like hydrogen sulfide ($H_2S$) as a source of chemical energy.

First Law of Thermodynamics

Energy is neither created nor destroyed; it just changes form.

Second Law of Thermodynamics

The state that energy conversions are not $100\%$ efficient, and some energy is lost as heat at each step.

Primary production

The synthesis of organic compounds from atmospheric or aqueous carbon dioxide ($CO_2$).

Biomass

The total mass of organisms in a given area.

Gross Primary Productivity (GPP)

The rate at which photosynthetic primary producers incorporate energy from the sun.

Net Primary Productivity (NPP)

The energy that remains in the primary producers after accounting for the organisms’ respiration and heat loss, calculated as $\text{NPP} = \text{GPP} - \text{Respiration}$.

Cellular Respiration

The conversion of glucose from photosynthesis to $ATP$.

Ecological Pyramids

Visualizations showing the relative amounts of parameters such as number of organisms, energy, and biomass across trophic levels.

Biomagnification

The build-up of toxins, such as $DDT$, mercury, or arsenic, in a food chain where concentration increases at higher trophic levels.

Silent Spring

A 1962 book by biologist Rachel Carson that described the detrimental effects of $DDT$ on birds and ecosystems.

Law of Conservation of Matter

Matter is neither created nor destroyed; it is moved around and transformed.

Biogeochemical cycle

The recycling of inorganic matter between living organisms and their environment, involving biological, geological, and chemical processes.

Hydrosphere

The area of the Earth where water movement and storage occurs, including rivers, lakes, oceans, groundwater, ice caps, and the atmosphere.

Sublimation

The process of water changing state directly from a solid (ice/snow) to a vapor.

Transpiration

The process where liquid water is absorbed by plant roots, moves through the vascular system, and evaporates off the leaves.

Non-renewable resource

A resource that is either regenerated very slowly or not at all, such as fossil fuels.

Eutrophication

A process where excess nutrients (nitrogen and phosphorus) cause algal blooms that deplete oxygen and kill aquatic life.

Dead zones

Coastal areas where phosphorus and nitrogen from fertilizers cause excessive microorganism growth, depleting oxygen and killing fauna.