biology

Plakortis

Plakortis is a biology 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 Plakortis rather than just read about it. In short: Plakortis is a genus of marine sponges in the order Homosclerophorida, first described by Franz Eilhard Schulze in 1880. Description Plakortis sponges are characterised by having: inorganic (spicular) skeletal complement Skeleton composed mainly of diods, triods, and/or calthrops in one size class Lophose diods, triods, or calthrops complement the main skeleton of non-lophose spicules no lophose spicules diactinal "…

Key takeaways

Plakortis belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Plakortis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Plakortis from memory before moving on to harder problems.

Reference excerpt

Plakortis is a genus of marine sponges in the order Homosclerophorida, first described by Franz Eilhard Schulze in 1880.

Description Plakortis sponges are characterised by having:

inorganic (spicular) skeletal complement Skeleton composed mainly of diods, triods, and/or calthrops in one size class Lophose diods, triods, or calthrops complement the main skeleton of non-lophose spicules no lophose spicules diactinal "microscleres" (microrhabs) in some species

Species List of accepted species:

Plakortis albicans Cruz-Barraza & Carballo, 2005 Plakortis angulospiculatus (Carter, 1879) Plakortis badabaluensis Ubare & Mohan, 2016 Plakortis bergquistae Muricy, 2011 Plakortis clarionensis Cruz-Barraza, Vega & Carballo, 2014 Plakortis communis Muricy, 2011 Plakortis copiosa Pulitzer-Finali, 1993 Plakortis dariae Ereskovsky, Lavrov & Willenz, 2014 Plakortis deweerdtaephila Vicente, Zea & Hill, 2016 Plakortis edwardsi Ereskovsky, Lavrov & Willenz, 2014 Plakortis erythraena Lévi, 1958 Plakortis fromontae Muricy, 2011 Plakortis galapagensis Desqueyroux-Faúndez & van Soest, 1997 Plakortis halichondrioides (Wilson, 1902) Plakortis hooperi Muricy, 2011 Plakortis insularis Moraes & Muricy, 2003 Plakortis japonica (Hoshino, 1977) Plakortis kenyensis Pulitzer-Finali, 1993 Plakortis lita de Laubenfels, 1954 Plakortis mesophotica Idan, Shefer, Feldstein & Ilan, 2021 Plakortis microrhabdifera Moraes & Muricy, 2003 Plakortis myrae Ereskovsky, Lavrov & Willenz, 2014 Plakortis nigra Lévi, 1953 Plakortis petrupaulensis Domingos, Moraes & Muricy, 2013 Plakortis potiguarensis Domingos, Moraes & Muricy, 2013 Plakortis pulvillus Samaai, Pillay & Janson, 2019 Plakortis quasiamphiaster Díaz & van Soest, 1994 Plakortis ruetzleri Lage, Muricy, Ruiz & Pérez, 2018 Plakortis simplex Schulze, 1880 Plakortis spinalis Domingos, Moraes & Muricy, 2013 Plakortis symbiotica Vicente, Zea & Hill, 2016 Plakortis zyggompha (de Laubenfels, 1934)

Literature

Chemical and medecinal properties Paul Ralifo; Laura Sanchez; Nadine C Gassner; Karen Tenney; R Scott Lokey; Theodore R Holman; Frederick A Valeriote; Phillip Crews (1 January 2007). "Pyrroloacridine alkaloids from Plakortis quasiamphiaster: structures and bioactivity". Journal of Natural Products. 70 (1): 95–99. doi:10.1021/np060585w. ISSN 0163-3864. PMC 1839848. PMID 17253856. Wikidata Q42875300. Sridevi Ankisetty; Deborah J. Gochfeld; M. Cristina Diaz; Shabana I. Khan; Marc Slattery (25 August 2010). "Chemical constituents of the deep reef caribbean sponges Plakortis angulospiculatus and Plakortis halichondrioides and their anti-inflammatory activities". Journal of Natural Products. 73 (9): 1494–1498. doi:10.1021/np100233d. ISSN 0163-3864. PMID 20738102. Wikidata Q84803121. Florecita S. De Guzman; Francis J. Schmitz (July 1990). "Peroxy Aliphatic Esters from the Sponge Plakortis lita". Journal of Natural Products. 53 (4): 926–931. doi:10.1021/np50070a021. ISSN 0163-3864. Wikidata Q104397018. J. C. Braekman; D. Daloze; S. De Groote; J. B. Fernandes; R. W. Van Soest (3 July 1998). "New polyketides from the sponge Plakortis sp". Journal of Natural Products. 61 (8): 1038–1042. doi:10.1021/np980096z. ISSN 0163-3864. PMID 9722495. Wikidata Q77171802. A Rudi; Y Kashman (October 1993). "Three new cytotoxic metabolites from the marine sponge Plakortis halichondrioides". Journal of Natural Products. 56 (10): 1827–1830. doi:10.1021/np50100a027. ISSN 0163-3864. PMID 8277322. Wikidata Q72696133.

References

Illustrations

Worked examples

Example 1 — a first encounter with Plakortis

Start with the simplest possible case. Write down what Plakortis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Plakortis 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 Plakortis 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 Plakortis

In research: Plakortis appears in biology 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 Plakortis 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: Plakortis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Homoscleromorpha, Sponge genera, Sponge stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Plakortis 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 Plakortis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Plakortis 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.
Explain Plakortis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Plakortis in simple terms?

Plakortis is a genus of marine sponges in the order Homosclerophorida, first described by Franz Eilhard Schulze in 1880. Description Plakortis sponges are characterised by having: inorganic (spicular) skeletal complement Skeleton composed mainly of diods, triods, and/or calthrops in one size class…

Why does Plakortis matter?

Because it connects several biology 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 Plakortis?

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 Plakortis.