The composition and evolution of the Earth's atmosphere key terms

photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll, removing carbon dioxide from the atmosphere.

carbon dioxide removal

The process by which carbon dioxide is taken out of the atmosphere, primarily through photosynthesis by plants and algae.

photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll, producing oxygen as a byproduct.

oxygen levels

The concentration of oxygen in the atmosphere, which increased gradually due to the activity of photosynthetic organisms.

atmospheric oxygen

The oxygen present in the Earth's atmosphere, which increased due to photosynthesis and is essential for the development of complex life.

photosynthesis

The process by which algae and plants convert carbon dioxide and water into glucose and oxygen using sunlight, contributing to the increase of atmospheric oxygen.

atmospheric oxygen

The amount of oxygen present in the Earth's atmosphere, which has changed over geological time.

photosynthesis

The process by which algae and plants convert carbon dioxide and sunlight into oxygen and glucose.

carbon dioxide

A colorless gas that is a significant component of Earth's atmosphere and is produced by respiration and combustion.

oceans

Large bodies of saltwater that cover about 71% of the Earth's surface and play a crucial role in the carbon cycle.

carbonate precipitates

Solid compounds formed when dissolved carbon dioxide reacts with minerals in water.

dissolved carbon dioxide

Carbon dioxide that is mixed in water, contributing to the formation of carbonate precipitates.

carbonate precipitates

Solid compounds formed when dissolved carbon dioxide reacts with minerals in water.

sedimentary rocks

Rocks formed from the accumulation and compaction of mineral and organic particles over time.

carbonates

Compounds containing the carbonate ion (CO3^2-) that marine organisms use to form shells and skeletons.

marine organisms

Living organisms that inhabit the ocean and utilize carbonates to create structures such as shells and skeletons.

fossil fuels

In How carbon dioxide decreased, fossil fuels means natural substances formed from the remains of dead organisms, which trap carbon. This matters in The composition and evolution of the Earth's atmosphere because it supports the learning objective to explain that some carbon was trapped in fossil fuels formed from dead organisms. Use fossil fuels only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

carbon trapping

The process by which carbon is stored in fossil fuels, reducing atmospheric carbon dioxide levels.

limestone

A sedimentary rock primarily composed of calcium carbonate, formed from the remains of marine organisms and acts as a long-term carbon store.

fossil fuels

Natural substances such as coal, crude oil, and natural gas formed from the remains of dead organisms, serving as long-term carbon stores.

carbon dioxide

A colorless gas that is a significant greenhouse gas and was abundant in the Earth's early atmosphere.

geological time

A time scale used by geologists and other Earth scientists to describe the timing and relationships of events in Earth's history.

carbon cycle

The continuous process by which carbon is exchanged between the Earth's atmosphere, land, water, and living organisms.

carbon dioxide removal

The process of reducing the concentration of carbon dioxide in the atmosphere, often linked to natural processes or human activities.