Stellar Evolution, Earth Systems, and Ecology Lecture Notes

Vocabulary-style flashcards covering stellar evolution, geological processes, soil science, and ecological principles based on lecture transcripts.

Star

A glowing ball of gas held together by its own gravity and powered by nuclear fusion in its core.

Protostar

An early stage of a star that develops as a nebula contracts, flattens, spins faster, and heats up before nuclear fusion occurs.

Nebula

A large cloud of gas and dust formed by the clumping and gravitational attraction of matter in space.

Nuclear Fusion

The merging of elements to form a new element or substance, initiated by gravitational attraction at a high density core.

Triple Alpha Process

The fusion of three alpha particles ($He^4$ nuclei) to form a carbon nucleus ($^{12}C$).

Supernova (Type I)

An explosion occurring when a white dwarf in a binary system either collides with another white dwarf or pulls too much matter from its nearby star.

Supernova (Type II)

An explosion caused when the outward pressure from nuclear fuel burning can no longer resist the inward squeeze of gravity in a star.

Kilonova

A blast occurring when two neutron stars merge, creating an event 1,000 times brighter than a classical nova.

Differentiation

A process where a mixture of materials separates out into constituent parts, such as the separation of Earth into crust, mantle, and core.

Iron Catastrophe

The event where Earth became molten and heavy materials like iron and nickel sank toward the center after reaching iron's melting temperature.

Inner Core

A dense sphere of solid iron and nickel at the center of the Earth.

Outer Core

A layer of molten iron and nickel that surrounds the inner core of the Earth.

Mantle

The mostly solid bulk of Earth's interior located between the core and the thin outer crust.

Asthenosphere

The soft, slowly flowing layer of the upper mantle beneath the lithosphere that allows tectonic plates to move.

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Rock Cycle

A series of processes on the surface and inside Earth that slowly changes rocks from one kind to another.

Endogenic Processes

Forces originating within Earth that affect its surface, such as plate tectonics and volcanic eruptions.

Exogenic Processes

Forces generally originating in the atmosphere that shape Earth's surface, such as erosion by water, wind, or glaciers.

Plate Tectonics

A theory describing how Earth's lithosphere is divided into rigid plates whose movements produce geological events and landforms.

Convergent Boundary

A plate boundary where two plates move toward each other.

Trench

A deep, steep-sided canyon in the ocean floor associated with subduction at a convergent boundary.

Subduction

The process where an oceanic plate slides beneath another plate into the mantle and begins to melt.

Divergent Boundary

A plate boundary where two plates move away from each other.

Mid-Ocean Ridge

An underwater mountain chain where new ocean floor is formed at a divergent boundary.

Transform Boundary

A plate boundary where two plates move past each other in opposite directions.

Orogenesis

The collective processes that result in the formation of mountains.

Partial Melting

The process where only some minerals in a rock melt to form magma while others remain solid due to different melting temperatures.

Renewable Resource

A resource that can be replenished over a fairly short time span such as months, years, or decades.

Nonrenewable Resource

A resource that takes millions of years to form and accumulate, such as fossil fuels and certain metals.

Hydrothermal Solutions

Hot waters in the Earth's crust that move through rock to dissolve and precipitate minerals in fractures and cavities.

Ore

A naturally occurring solid material from which a metal or valuable mineral can be profitably extracted.

Percent Yield

The measure of the amount of ore as compared to the amount of rock removed, calculated as $(\text{Mass of Ore} / \text{Mass of Rock}) \times 100$.

Placer Deposit

A deposit formed when heavy minerals settle where a river current slows down.

Acid Mine Drainage

Pollution caused when sulfuric acid and dissolved materials like lead or arsenic wash from mines into water systems.

Reclamation

The process of restoring mined land to a natural or economically usable state.

Geothermal Energy

Energy derived from steam or hot water produced from hot or molten underground rocks.

Biomass Energy

Renewable energy derived from burning organic materials such as wood and alcohol.

Tragedy of the Commons

A situation where individuals acting in their own self-interest deplete a shared resource, eventually causing everyone to suffer.

Weathering

The breaking down and changing of rocks at or near the Earth's surface.

Frost Wedging

A type of mechanical weathering where water freezes and expands in rock cracks, enlarging them over time.

Exfoliation

Mechanical weathering caused by upward expansion where outer slabs of rock separate and break loose.

Hydrolysis

Chemical weathering that occurs when water reacts with minerals like feldspar to produce clay and salts.

Regolith

A layer of rock and mineral fragments produced by weathering that supports plant growth.

Soil Texture

The proportions of different particle sizes (clay, silt, and sand) in soil.

Primary Macronutrients

The three nutrients needed by plants in the highest concentrations: Nitrogen (N), Phosphorus (P), and Potassium (K).

Humus

The organic matter in soil composed of living and dead things in various states of decomposition.

Loam

The best soil texture for plant growth, providing a balance of water retention and nutrient storage.

Soil Horizon

A specific zone or layer of soil divided based on variations in composition, texture, structure, and color.

Topsoil (A Horizon)

The soil layer containing a mixture of mineral matter and organic matter; the lower limit for most plant roots.

Eluviation

The removal of dissolved or suspended material from soil layers by water movement, typically forming the E Horizon.

Soil Salinization

The excessive accumulation of water-soluble salts in soil resulting from evaporation.

Ecology

The scientific study of how living things interact with each other and their environment.

Community

All the populations of different species that live and interact with each other in a particular place.

Biome

A region of Earth characterized by a particular climate and specific types of plant life.

Abiotic Factor

A nonliving physical or chemical part of an ecosystem, such as humidity, salinity, or pH.

Saprotroph

A decomposer that feeds on non-living organic matter by secreting digestive enzymes and absorbing the products.

10% Rule

The principle that only about 10 percent of energy is passed upward from one trophic level to the next.

Biomagnification

The increasing concentration of toxins in organisms as they ingest other plants or animals in which the toxins are dispersed.

Competitive Exclusion Principle

States that two species cannot occupy the same niche in a habitat if they are competing for all the same resources.

Carrying Capacity

The maximum sustainable size a population can reach in a given ecosystem.

Density-Dependent Limiting Factor

A limiting factor that occurs when a population reaches a certain size, such as competition, predation, or disease.

r-selected Species

Species characterized by numerous small offspring, short life spans, and rapid maturation, often thriving in disturbed habitats.

K-selected Species

Species with relatively stable populations that produce few but large offspring and provide extended parental care.

Primary Succession

Ecological succession that begins in an area where no soil is present, such as bare rock.

Keystone Species

A species that has a disproportionately large impact on its ecosystem relative to its abundance.

Invasive Species

Non-native species that spread and cause environmental, ecosystem, or economic damage often due to a lack of predators.