Earth and Life Science

Steady State Theory

The theory that the universe is unchanging; new matter continuously forms to fill the space left by receding galaxies.

Pulsating Theory

The theory that the universe undergoes cycles of expansion and contraction, eventually collapsing and re-expanding.

Big Bang Theory

The theory that the universe originated from a primeval nucleus that exploded about 20 billion years ago, leading to expansion.

Nebular Hypothesis

The theory that the solar system formed from a spinning cloud of gas (nebula), collapsing to form the Sun and planets.

Accretion Theory

The theory that a protosun pulled interstellar material, forming planets through accretion.

Tidal Theory

The theory that a large body passing near the protosun pulled out gaseous materials, which condensed into planets.

Geosphere

The solid Earth, including rocks, mountains, and the core.

Hydrosphere

All water on Earth, including oceans, rivers, and groundwater.

Atmosphere

A layer of gases surrounding Earth, primarily composed of 78% nitrogen and 21% oxygen.

Biosphere

All living organisms interacting with other subsystems of the Earth.

Igneous Rocks

Rocks formed from cooled molten rock; can be intrusive (cools slowly) or extrusive (cools quickly).

Sedimentary Rocks

Rocks formed by the compaction of sediments; includes detrital and chemical types.

Metamorphic Rocks

Rocks formed by transforming existing rocks under heat and pressure.

Weathering

The breakdown of rocks at Earth's surface through physical or chemical processes.

Erosion

The removal and transport of weathered material by wind, water, or ice.

Deposition

The accumulation of sediments in a new location after they have been eroded.

Tectonic Movements

Movements of the Earth's crust driven by internal heat, including earthquakes and volcanic activity.

Crustal Deformation

Changes in the Earth's crust due to stress types such as tensional, compressional, and shear.

Earthquake

A sudden release of energy along faults that causes ground shaking.

Volcanic Eruptions

Explosive or quiet outbursts of magma, influenced by composition and gas content.

Tropical Cyclones

Large storms characterized by strong winds and heavy rain.

Photosynthesis

The process by which plants convert sunlight into chemical energy.

Cellular Respiration

The process by which organisms convert glucose into usable energy (ATP).

Reproduction

Essential biological process for the continuation of species.

Genetic engineering

The manipulation of genes to produce desirable traits in organisms.

Homeostasis

The maintenance of internal balance within organisms, such as body temperature stability.

Natural selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Ecosystems

Communities of living organisms and their interactions with the non-living environment.

Human impact

Effects of human activities, such as pollution, deforestation, and climate change, on natural ecosystems.