Emission spectrumThe emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an electron making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum.
HeterotrophA heterotroph (ˈhɛtərəˌtroʊf,_-ˌtrɒf; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but not producers. Living organisms that are heterotrophic include all animals and fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition.
TundraIn physical geography, tundra (ˈtʌndrə,_ˈtʊn-) is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term tundra comes through Russian тундра (tundra) from the Kildin Sámi word тӯндар (tūndâr) meaning "uplands", "treeless mountain tract". There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra. Tundra vegetation is composed of dwarf shrubs, sedges, grasses, mosses, and lichens. Scattered trees grow in some tundra regions.
SwampA swamp is a forested wetland. Swamps are considered to be transition zones because both land and water play a role in creating this environment. Swamps vary in size and are located all around the world. The water of a swamp may be fresh water, brackish water, or seawater. Freshwater swamps form along large rivers or lakes where they are critically dependent upon rainwater and seasonal flooding to maintain natural water level fluctuations. Saltwater swamps are found along tropical and subtropical coastlines.
Holdridge life zonesThe Holdridge life zones system is a global bioclimatic scheme for the classification of land areas. It was first published by Leslie Holdridge in 1947, and updated in 1967. It is a relatively simple system based on few empirical data, giving objective criteria. A basic assumption of the system is that both soil and the climax vegetation can be mapped once the climate is known. While it was first designed for tropical and subtropical areas, the system now applies globally.
