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The earliest megafossils of land plants were thalloid organisms, which dwelt in fluvial wetlands and are found to have covered most of an early Silurian flood plain. They could only survive when the land was waterlogged. [22] There were also microbial mats. [23] Once plants had reached the land, there were two approaches to dealing with ...
Cycads were also common, as were ginkgos and tree ferns in the forest. Smaller ferns were probably the dominant undergrowth. Caytoniaceous seed ferns were another group of important plants during this time and are thought to have been shrub to small-tree sized. [16] Ginkgo-like plants were particularly common in the mid- to high northern latitudes.
[64] [65] Meanwhile, in Switzerland, from 1554, Conrad Gessner (1516 – 1565) made regular explorations of the Swiss Alps from his native Zurich and discovered many new plants. He proposed that there were groups or genera of plants. He said that each genus was composed of many species and that these were defined by similar flowers and fruits.
They were photosynthetic and multicellular, indicating that plants evolved much earlier than originally thought. [53] 750 Ma Beginning of animal evolution. [54] [55] 720–630 Ma Possible global glaciation [56] [57] which increased the atmospheric oxygen and decreased carbon dioxide, and was either caused by land plant evolution [58] or ...
The Ebers Papyrus – one of the most important medical papyri of ancient Egypt – was written around 1550 BCE, and covers more than 700 drugs, mainly of plant origin. [7] The first references to pills were found on papyri in ancient Egypt, and contained bread dough
C 3 plants preferentially use the lighter of two isotopes of carbon in the atmosphere, 12 C, which is more readily involved in the chemical pathways involved in its fixation. Because C 4 metabolism involves a further chemical step, this effect is accentuated. Plant material can be analysed to deduce the ratio of the heavier 13 C to 12 C.
Ornamental horticulture became highly developed during the development of Roman civilization. The administrators of the Roman Empire (c.100 BC–500 AD) actively exchanged information on agriculture, horticulture, animal husbandry, hydraulics, and botany. Seeds and plants were widely shared.
At the beginning of the 18th century, about twenty thousand plant species were known, versus forty thousand at the beginning of the 19th century, and about 300,000 today. These expeditions were joined by many scientists, including botanists, such as the German explorer Alexander von Humboldt. Humboldt is often considered as father of ecology.