Earth and Environmental Science: Development of the Biosphere, Natural Hazards, Climate Change, and Resource Management

Vocabulary practice flashcards covering Module 5 to Module 8 topics including the development of the biosphere, geological processes, natural hazards, past climate evidence, global climate change, and sustainable resource and waste management.

Chemical Evolution Hypothesis

The hypothesis proposing that life originated on Earth through a sequence of natural chemical processes, transforming simple chemicals into organic molecules and eventually into primitive cells.

Panspermia

The hypothesis that life or its organic building blocks originated in outer space and were transported to Earth via comets or meteorites.

Urey-Miller Experiment

A laboratory experiment simulating primitive Earth conditions (water, atmospheric gases, and electrical discharge) that produced organic chemicals, including amino acids.

Chemosynthesis

A process carried out by ancient, anaerobic single-celled Archaea at deep-ocean hydrothermal vents, using energy from inorganic chemical compounds like hydrogen sulfide ($H_2S$) rather than sunlight.

Stromatolites

Layered biological structures built by photosynthetic cyanobacteria (blue-green bacteria) that played a primary role in releasing oxygen ($O_2$) into Earth's atmosphere around $2.5\,\text{Ga}$.

Endosymbiotic Hypothesis

The evolutionary theory stating that eukaryotic cell organelles, such as mitochondria, originated from mutually beneficial symbiotic relationships between distinct prokaryotic organisms.

Ediacaran Organisms

An ancient assemblage of soft-bodied multicellular animals that existed prior to the Cambrian explosion.

Cambrian Explosion

A rapid appearance and diversification of complex animal life in the fossil record characterized by hard body parts, evolutionary predation, and enhanced fossil preservation.

Banded Iron Formations (BIFs)

Sedimentary rock units formed mainly during the Archaean and early Proterozoic eons, consisting of alternating layers of iron-rich minerals (e.g., hematite, magnetite) and silica created when ocean iron oxidised and precipitated out as oxygen increased.

Ozone Layer

A stratospheric region composed of ozone ($O_3$) formed from atmospheric oxygen ($O_2$) reacting with solar UV radiation, which absorbs harmful UV-B and UV-C rays and reduces DNA damage for terrestrial and shallow-water life.

Snowball Earth Hypothesis

A hypothesis proposing episodes of global glaciation during the Proterozoic Eon, driven by decreased atmospheric greenhouse gases ($CO_2$) and high solar reflection (albedo) from extensive surface ice cover.

Plate Tectonic Supercycle

A cyclical geological process taking approximately $300-500\text{ million years}$, during which Earth's continental landmasses repeatedly join into supercontinents and subsequently rift apart.

Cratons

Ancient, stable sections of continental crust that survive successive plate tectonic supercycles, providing preserved geological evidence of early continental configurations.

Uniformitarianism

The foundational geological axiom assuming that the same natural physical processes and scientific laws operating in the present operated throughout deep geological time.

Law of Superposition

A core principle of stratigraphy stating that in undisturbed sedimentary rock layers, older strata remain below, while younger strata lie higher up.

Index Fossils

Fossils of widespread organisms that flourished for a relatively short time span (such as microscopic plankton with silica skeletons), used to identify specific time periods and correlate rock layers across geographical distances.

Mass Extinction

A catastrophic event resulting in the loss of $30\%$ or more of all global species within a period of $2\text{ million years}$ or less.

End-Permian Extinction

The largest recorded mass extinction event in Earth's history, eliminating around $95\%$ of species, linked to massive flood basalt volcanism in Siberia and China over approximately $600{,}000\text{ years}$.

K-Pg Extinction Event

A major mass extinction event around $66\text{ million years}$ ago that wiped out approximately $60\%$ of species (including non-avian dinosaurs), caused by a asteroid impact crater in Mexico combined with massive Indian volcanism.

Effusive Eruption

A non-explosive volcanic eruption involving mafic magma with low silica content and low viscosity, resulting in fluid lava flows typical of divergent boundaries and hotspots.

Explosive Eruption

A highly violent volcanic eruption driven by felsic magma with high silica content, high viscosity, and gas accumulation, producing pyroclastic flows, ash clouds, and lahars at subduction zone boundaries.

Pyroclastic Flow

A destructive, fast-moving, and extremely hot current of gas, ash, and rock fragments expelled during an explosive volcanic eruption.

Lahar

A fast-moving mudflow or debris flow composed of pyroclastic material, rocky debris, and water flowing down the slope of a volcano.

East Coast Low (ECL)

An intense low-pressure storm system forming off the east coast of Australia that can produce severe weather, intense rainfall, and coastal flooding.

Natural Greenhouse Effect

The absorption and re-radiation of infrared radiation by atmospheric greenhouse gases ($H_2O$, $CO_2$, $CH_4$, $N_2O$), keeping Earth about $32\,^\circ\text{C}$ warmer on average ($14\,^\circ\text{C}$ vs $-18\,^\circ\text{C}$ without an atmosphere).

Deccan & Siberian Traps

Immense continental flood basalt eruptions in Russia ($\sim 252\text{ Ma}$) and India ($\sim 66\text{ Ma}$) that released massive amounts of $CO_2$, $SO_2$, and ash, inducing severe climate changes and ocean acidification.

Milankovitch Cycles

Cyclical changes in Earth's orbital eccentricity ($\sim 100{,}000\text{ years}$), axial tilt ($\sim 41{,}000\text{ years}$), and precession ($\sim 26{,}000\text{ years}$) that alter the distribution of solar energy on Earth and trigger ice ages.

Climate Proxies

Measurable physical, chemical, or biological structures (such as oxygen isotope ratios, microfossils, tree rings, and coral growth bands) that substitute for direct past climate measurements.

Dendrochronology

The study of annual growth rings in trees to reconstruct historical temperature, rainfall, and fire activity over the last $\sim 5{,}000\text{ years}$.

Anthropogenic Greenhouse Effect

The enhanced global warming resulting from human activities—such as burning fossil fuels, agriculture, and land clearing—that increase atmospheric concentrations of $CO_2$, $CH_4$, and $N_2O$.

Ocean Acidification

The sustained reduction in ocean pH caused by seawater absorbing elevated levels of atmospheric $CO_2$, impairing shell and reef building in marine organisms like corals.

Geo-engineering

Large-scale technological interventions proposed to cool Earth or capture carbon dioxide ($CO_2$) from the atmosphere, such as stratospheric aerosol spraying, marine cloud brightening, and carbon capture and storage (CCS).

Mining Reclamation

The practice of restoring land altered by mining through terrain reshaping, topsoil replacement, and re-establishing native vegetation to achieve a safe, stable, and productive state.

Leachate

A contaminated liquid generated as rainwater dissolves soluble chemicals and pollutants from rotting waste, posing severe risks to surrounding soils, streams, and groundwater.

Bioreactor Landfill

An engineered waste facility using synthetic/clay membranes, liquid recirculation, and methane gas capture for power generation to speed up waste decomposition and minimize ecological harm.

5 R's Waste Hierarchy

A framework ranking solid waste management strategies from most preferred to least preferred: Reduce, Re-use, Recycle, Recover, and Residual (landfill).

E-Waste

Discarded electronic products (e.g., computers, cell phones, televisions) that contain both toxic heavy metals and valuable recyclable resources.

Sustainability

The practice of using natural resources at a rate that allows them to replenish, meeting current human needs without compromising the ability of future generations to meet their own needs.

Overharvesting

The extraction or harvesting of biological resources (e.g., fish, timber, soil, groundwater) at rates faster than populations or natural cycles can naturally regenerate.