astronomy

Johan Petter Norrlin

Johan Petter Norrlin is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Johan Petter Norrlin rather than just read about it. In short: Johan Petter Norrlin (6 September 1842 – 7 January 1917) was a Finnish botanist and a professor of botany at the University of Helsinki from 1879 to 1903. He was a pioneer of plant geography in Finland, and is also well known for his work on lichens and on the taxonomy of the apomictic taxa of the plant genera Hieracium and Pilosella.

Key takeaways

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Reference excerpt

Johan Petter Norrlin (6 September 1842 – 7 January 1917) was a Finnish botanist and a professor of botany at the University of Helsinki from 1879 to 1903. He was a pioneer of plant geography in Finland, and is also well known for his work on lichens and on the taxonomy of the apomictic taxa of the plant genera Hieracium and Pilosella.

Life and education Johan Petter Norrlin was born on 6 September 1842 in Hollola, Finland. Norrlin's parents were Nils Nathanael Norrlin and Fredrika Charlotta Lang. He became a student in 1862 at Porvoo high school, and graduated in 1866 as a forester from Evo Forestry College. Norrlin then studied at the University of Helsinki. It was around this time that he met Edvard August Vainio (then named Edvard Lang), the neighbour's son, who was nearly 11 years younger. Young Edvard Lang often accompanied Norrlin on his botanical excursions around Lake Vesijärvi in the summers of 1868 and 1869, helping him collect samples of plants and cryptogams (mosses and lichens). Due to Norrlin's influence, Vainio chose to study botany at university, and his first publications were about plant geography and floristics; Vainio would later become a world-renowned lichenologist. In 1873, Norrlin married Lang's sister.

Norrlin graduated with a bachelor's and master's degree in philosophy in 1869 and a licentiate and doctorate in philosophy in 1879. This gave him the qualifications to become a docent. Norrlin was an associate professor at the University of Helsinki from 1879 to 1903. Norrlin was William Nylander's foremost student, and he became the first expert on Finnish lichens. He was primarily active as a lichen collector, plant geographer and Hieracium researcher. While travelling in different parts of Finland and Lapland, he discovered a large number of interesting or new species that would be formally described by Nylander. Together with Nylander, he published the exsiccata Herbarium lichenum Fenniae (1875–1882). Later on he published two exsiccatae with Hieracium and Pilosella species. The works Bidrag till sydöstra Tavastlands Flora and Flora Kareliae Onegensis I (1871) are examples of Finnish plant geography research in terms of plant topography. Norrlin was instrumental in developing the biogeographic divisions of East Fennoscandia. He showed that Aunus, Karelia and the Kola Peninsula belong to the Finnish natural science area (even though they are geographically in Russia), a conclusion that was later verified with geological surveys. He was named honorary member of the Societas pro Fauna et Flora Fennica in 1912. Norrlin died at the age of 74 in Helsinki in 1917.

Legacy Norrlin developed a system called the Norrlin Scale to classify plant prevalence. In this ten-grade scale, the first seven grades (1, 2 = sparse; 3, 4 = scattered; 5, 6, 7 = abundant/plenty) are based on distances (=density) between the individuals of each species, while the upper three grades (8–10) relate to the admixture of other species, overall between 7.5 species (=grade 8) and one species (=grade 10). According to Finnish conservationist and teacher Reino Kalliola, Norrlin's work laid the foundation for future studies of Finnish phytogeography. His ideas were used in the later work of Aimo Kaarlo Cajander, and by phytogeographers of future generations. The International Plant Names Index lists 638 species that were named by Norrlin. The botanical periodical Norrlinia is named after Norrlin. It is a publication series of the Botanical Museum of the Finnish Museum of Natural History at the University of Helsinki. Norrlin is also honoured in the lichen genus name Norrlinia Theiss. & Syd. (1918), the lichen species Physcia norrlinii Vain. (1921), Porina norrlinii Vain. (1921), Roesleria norrlinii Vain. (1927), Verrucaria norrlinii Pykälä & Myllys (2024), and the plant Hieracium norrlinii Nägeli & Peter.

Selected publications 1870. Bidrag till Sydöstra Tavastlands flora (Contribuciones a la flora del sudeste Häme). 123 pp. 1875. Flora Kareliae onegensis: Lichenes. 46 pp. 1891. Minnesord öfver Sextus Otto Lindberg. Acta Societatis scientiarum Fennicae. Ed. Societas scientiarum Fennicae. 36 pp. 1895. Pilosellæ boreales: præcipue floræ fennicæ novæ. Volumen 12 y 14 de Acta Societatis pro fauna et flora Fennica. 83 pp. 1906. Suomen keltanot. 154 pp. (Finnish language) 1912. Nya nordiska Hieracia beskrifna af J. P. Norrlin 1923. Lectio praecursoria. Volumen 23 de Acta forestalia Fennica. 1913. Minnesord öfver professor William Nylander, af J. P. Norrlin. Volumen 44 de Acta Societatis Scientiarum Fennicae. Ed. Finska litteratursällskapets tryckeri. 43 pp.

References

Illustrations

Worked examples

Example 1 — a first encounter with Johan Petter Norrlin

Start with the simplest possible case. Write down what Johan Petter Norrlin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Johan Petter Norrlin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Johan Petter Norrlin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Johan Petter Norrlin

In research: Johan Petter Norrlin appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Johan Petter Norrlin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Johan Petter Norrlin is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1842 births, 1917 deaths, 19th-century Finnish botanists, so understanding it makes those chapters shorter.
In everyday life: Look for Johan Petter Norrlin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Johan Petter Norrlin in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Johan Petter Norrlin means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
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Frequently asked questions

What is Johan Petter Norrlin in simple terms?

Why does Johan Petter Norrlin matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Johan Petter Norrlin?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Johan Petter Norrlin.