Evidence for Evolution: Fossils Fossils are the?preserved remains?of organisms, or the traces left by organisms, such as footprints, burrows and faeces These remains can be?preserved,?e.g. in?rocks...
Evolution Defined Species?do not stay the same over time; the species that we see around us today have developed over millions of years This process of species change is known as?evolution Evolutio...
Drawing the Carbon Cycle The many processes by which carbon is transferred from one store to another are collectively known as the?carbon cycle During the carbon cycle, carbon is present in both?or...
Industrialisation & Increased Carbon Dioxide Atmospheric carbon dioxide levels have?fluctuated throughout Earth's history?due to events such as volcanic eruptions and the weathering of limeston...
Greenhouse Gases & Climate Patterns Greenhouse gases?absorb infrared radiation emitted by the earth, causing the atmosphere to warm Without greenhouse gases, the earth would be much colder The?...
The Main Greenhouse Gases When?radiation from the sun?hits the earth, it is?radiated back?from the earth's surface as?long-wave radiation A?greenhouse gas?is a gas that?absorbs?this re-radiated rad...
Formation of Peat Under normal conditions the tissues of dead organisms are completely broken down by decomposers known as?saprotrophs?and?detritivores These decomposers require specific conditions...
Methanogenesis Methane?(CH4) is a simple?hydrocarbon It is present as a?gas?in the atmosphere, and underground, and is the main component of?natural gas?fossil fuel Methane can be produced by the?n...
Respiration & Carbon Dioxide All living cells carry out some form of cellular?respiration, from bacteria, to plants, to animals Many organisms carry out?aerobic respiration Aerobic respiration ...
