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Matthias Jakob Schleiden (German: [maˈtiːas ˈjaːkɔp ˈʃlaɪdn̩]; [1] [2] 5 April 1804 – 23 June 1881) was a German botanist and co-founder of cell theory, along with Theodor Schwann and Rudolf Virchow.
From these conclusions about plants and animals, two of the three tenets of cell theory were postulated. 1. All living organisms are composed of one or more cells 2. The cell is the most basic unit of life. Schleiden's theory of free cell formation through crystallization was refuted in the 1850s by Robert Remak, Rudolf Virchow, and Albert ...
The book has been called "a conspicuous milestone in nineteenth century biology" by Karl Sudhoff and "epoch making" By Francis Münzer. [3] The book, originally published in German, was translated to English in 1847 by Henry Spencer Smith in an edition that also contained the treatise Phytogenesis, by Matthias Schleiden. [4]
In his 1838 publication on phytogenesis, Schleiden declared the cell as the fundamental unit of all plants and identified the cell nucleus, which was discovered in 1831, as an essential factor in plant growth. [6] The cellular theory of plant organism structure brought about a reorientation in botany. Before this, botany was primarily focused ...
Crucial to this doctrine are the ideas that life comes from non-life and that no causal agent, such as a parent, is needed. Supposed examples included the seasonal generation of mice and other animals from the mud of the Nile , the emergence of fleas from inanimate matter such as dust, or the appearance of maggots in dead flesh.
Biologists can study life at multiple levels of organization, [1] from the molecular biology of a cell to the anatomy and physiology of plants and animals, and the evolution of populations. [1] [6] Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use.
Panspermia did not get much scientific support because it was largely used to deflect the need of an answer instead of explaining observable phenomena. Although the interest in panspermia grew when the study of meteorites found traces of organic materials in them, it is currently accepted that life started locally on Earth.
The Rare Earth hypothesis argues that planets with complex life, like Earth, are exceptionally rare.. In planetary astronomy and astrobiology, the Rare Earth hypothesis argues that the origin of life and the evolution of biological complexity, such as sexually reproducing, multicellular organisms on Earth, and subsequently human intelligence, required an improbable combination of astrophysical ...