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In ecology, stratification refers to the vertical layering of a habitat; the arrangement of vegetation in layers. [1][2] It classifies the layers (sing. stratum, pl. strata) of vegetation largely according to the different heights to which their plants grow. The individual layers are inhabited by different animal [3] and plant communities ...
The term stratification can be traced back to at least 1664 in John Evelyn's Sylva, or A Discourse of Forest-Trees and the Propagation of Timber, [2] where seeds were layered (stratified) between layers of moist soil and the strata were exposed to winter conditions. Thus, stratification became the process by which seeds were artificially ...
Seventeen countries grew a total of 55.2 million hectares of genetically modified maize and fifteen grew 23.9 hectares of genetically modified cotton. Nine million hectares of genetically modified canola was grown with 8 million of those in Canada. Other GM crops grown in 2014 include Alfalfa (862 000 ha), sugar beet (494 000 ha) and papaya (7 ...
Description. Pinus sylvestris is an evergreen coniferous tree growing up to 35 metres (115 feet) in height [4] and 1 m (3 ft 3 in) in trunk diameter when mature, [5] exceptionally over 45 m (148 ft) tall and 1.7 m (51⁄2 ft) in trunk diameter on very productive sites. The tallest on record is a tree over 210 years old growing in Estonia which ...
Many plants are well known for natural cloning ability, including blueberry plants, Hazel trees, the Pando trees, [10] [11] the Kentucky coffeetree, Myrica, and the American sweetgum. It also occurs accidentally in the case of identical twins, which are formed when a fertilized egg splits, creating two or more embryos that carry identical DNA.
Secondary succession is the secondary ecological succession of a plant's life. As opposed to the first, primary succession, secondary succession is a process started by an event (e.g. forest fire, harvesting, hurricane, etc.) that reduces an already established ecosystem (e.g. a forest or a wheat field) to a smaller population of species, and as such secondary succession occurs on preexisting ...
Assisted migration is a specific type of species introduction. Species introduction is any act of establishing a species in a habitat it does not currently occupy. It often refers to a long-distance relocation, such as the accidental introduction of an invasive species from one continent to another, or the intentional relocation of a species in decline to a habitat where it can persist.
Stratified sampling example. In statistical surveys, when subpopulations within an overall population vary, it could be advantageous to sample each subpopulation (stratum) independently. Stratification is the process of dividing members of the population into homogeneous subgroups before sampling. The strata should define a partition of the ...