Biology 1110 - Lecture 10: Biomes and Nutrients

Vocabulary practice flashcards covering ecological levels, terrestrial biomes, organic versus inorganic molecules, metabolic processes, biogeochemical cycles (carbon and nitrogen cycles), and anthropogenic environmental impacts from Biology 1110 Lecture 10.

Ecology

The scientific study of interactions between organisms and the biotic and abiotic components of their environments.

Community

An assemblage of the populations of all the species of living organisms inhabiting a common environment and interacting with one another.

Ecosystem

The community of all living organisms along with all of the non-living (abiotic) components of the environment present at a given place and time.

Biome

A major ecosystem type or life zone classified on the basis of dominant vegetation and regional climatic conditions.

Tundra

A high-latitude, polar biome characterized by extreme cold, low precipitation in the form of snow, permafrost, small shrubs, and lichens with an absence of trees.

Permafrost

A layer of ground that remains frozen year-round, characteristic of the arctic tundra.

Northern Coniferous Forest (Taiga)

A northern midlatitude, temperate-zone biome characterized by extreme cold winters, warm dry summers, and forests dominated by cone-bearing trees like pine, spruce, and fir.

Temperate Broadleaf Forest

A midlatitude, temperate-zone biome characterized by cool, rainy winters, hot, humid summers, and deciduous trees such as oak, maple, and beech.

Desert

A lower midlatitude, subtropical biome characterized by daytime heat, nighttime freezing temperatures, drought-tolerant vegetation, and precipitation of less than $30\,\text{cm}$ per year.

Organic Compounds

Chemical compounds that compose the bodies of living or dead organisms, such as proteins, carbohydrates, fats, and nucleic acids ($\text{DNA}$ and $\text{RNA}$).

Inorganic Compounds

Chemical compounds derived from non-living sources, such as carbon dioxide ($\text{CO}_2$), nitrate ($\text{NO}_3^-$), and atmospheric nitrogen gas ($\text{N}_2$).

Autotroph

An organism ("self-feeder") that synthesizes organic molecules from entirely abiotic, inorganic sources using light, carbon dioxide, and water.

Heterotroph

An organism ("other-feeder") that acquires organic molecules and building blocks by consuming and digesting other organisms.

Cellular Respiration

The metabolic process carried out by both autotrophs and heterotrophs to break down organic compounds to make $\text{ATP}$, releasing $\text{CO}_2$ into the environment.

Biogeochemical Cycle

A cyclical pathway tracking the circulation and transformation of organic and inorganic chemical compounds through ecosystems.

Nitrogen Gas ($\text{N}_2$)

An inorganic atmospheric gas composing approximately $70\%$ of Earth's atmosphere that cannot be utilized directly by eukaryotes because of its strong triple covalent bond.

Nitrogen Fixation

The biological process wherein specialized bacteria, often residing in plant root nodules, break the triple bond of $\text{N}_2$ gas to produce inorganic nitrogen compounds usable by plants.

Detritus

Non-living organic material containing bound organic compounds, including dead plants, dead plant parts, deceased animals, and fecal matter.

Decomposition

The breakdown of organic compounds in detritus by fungi, bacteria, and other decomposers, releasing inorganic nitrogen forms such as ammonia ($\text{NH}_3$) and ammonium ($\text{NH}_4^+$).

Nitrification

A two-step bacterial process where soil bacteria first convert ammonium ($\text{NH}_4^+$) into nitrite ($\text{NO}_2^-$), and a second group of soil bacteria converts nitrite into nitrate ($\text{NO}_3^-$).

Nitrite ($\text{NO}_2^-$)

An inorganic nitrogen compound produced by soil bacteria during Step 1 of nitrification that cannot be used by plants as a nitrogen source.

Nitrate ($\text{NO}_3^-$)

An inorganic nitrogen compound produced during Step 2 of nitrification that is readily absorbed and assimilated by plants to construct organic molecules.

Ammonium ($\text{NH}_4^+$)

An inorganic nitrogen ion released by decomposition and nitrogen fixation that can be directly absorbed by plants to synthesize proteins, $\text{DNA}$, and chlorophyll.

Denitrification

A biological process carried out by soil bacteria that consume nitrate ($\text{NO}_3^-$) and convert it back into atmospheric nitrogen gas ($\text{N}_2$).

Carbon Cycle

The global biogeochemical movement of carbon between biotic and abiotic reservoirs, primarily driven by the reciprocal processes of photosynthesis and cellular respiration.

Eutrophication

An environmental disturbance caused by excess agricultural nitrogen runoff that triggers an unsustainable algal bloom, subsequent microbial oxygen depletion, and mass aquatic mortality.

Fossil Fuels

Underground stores of organic carbon (such as coal, oil, and natural gas) formed under intense pressure over millions of years from undecomposed organic matter.

Greenhouse Gases

Atmospheric gases, including carbon dioxide ($\text{CO}_2$), nitrous oxide ($\text{N}_2\text{O}$), and methane ($\text{CH}_4$), that trap radiating heat, contributing to rising global temperatures.