biology

Stemec

Stemec 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 Stemec rather than just read about it. In short: Stemec is an extinct genus of Plotopteridae, a family of flightless seabird similar in biology with penguins, but more closely related to modern cormorants. The genus is known from terrains dated from the Late Oligocene Sooke Formation of British Columbia History and etymology Although the fossil remains of large marine birds like the Pelagornithid Cyphornis are known from the Sooke Formation of the Oligocene of Van…

Key takeaways

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

Reference excerpt

Stemec is an extinct genus of Plotopteridae, a family of flightless seabird similar in biology with penguins, but more closely related to modern cormorants. The genus is known from terrains dated from the Late Oligocene Sooke Formation of British Columbia

History and etymology Although the fossil remains of large marine birds like the Pelagornithid Cyphornis are known from the Sooke Formation of the Oligocene of Vancouver Island since 1894, the first remains of plotopterids from the formation were only discovered in 2013 in the vicinity of Sooke by Leah and Graham Suntok. In 2015, those remains were described by Gary Kaiser, Junya Watanabe and Marji Johns as the new genus and species Stemec suntokum, using as holotype the specimen RBCM.EH2014.032.0001.001, a nearly complete coracoid.

Etymology The genus name, Stemec, designate an indefinite long-necked black waterbird in the Coast Salish language native of the area in which the holotype was discovered. The type species name, suntokum, honours the family name of Leah and Graham Suntok, the discoverers of the holotype.

Description Stemec was a relatively small plotopterid, comparable in size with its Miocene relative Plotopterum. It is only known from a single right coracoid belonging to an adult bird, as proven by the smooth surface of the shaft, although two fragmentary tibiotarsi found in the same locality and similar to those of modern cormorants might have belonged to the genus, or to another small-sized plotopterid. The holotype coracoid is 74.8 mm long, 12.8 mm wide, and fairly complete, although erosion had damaged part of its surface. It shared more similarities with the known coracoid of Plotopterum than with those of the larger Tonsalinae plotopterids like Copepteryx and Tonsala. It was although mostly differenced from Plotopterum by several osteological specificities, including the raised and flat platform formed by the facies articularis humeralis, and the absence of a prominent groove formed by the sulcus supracoracoideus typical of the later genus.

Palaeobiology During the Oligocene of Vancouver Island, Stemec lived alongside the Desmostylian Cornwallius, the Aetiocetid Chonecetus and the Pelagornithid Cyphornis in a shallow marine environment rich in sessile fauna. The discovery of Stemec and its close relative Plotopterum in coastal deposits indicate that the latest and smallest plotopterids had costal habits, when the larger and older tonsalin plotopterids where pelagic feeders. Elements of their osteology indicates that they were not proficient swimmer like their larger, open sea specialist relatives, which may explain both the apparent lack of competition between larger and smaller plotopterids and the later survival of the latter form.

References

Worked examples

Example 1 — a first encounter with Stemec

Start with the simplest possible case. Write down what Stemec 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 Stemec 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 Stemec 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 Stemec

In research: Stemec 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 Stemec 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: Stemec is common in secondary-school and first-year university syllabi. It links to neighbouring topics Extinct flightless birds, Fossil taxa described in 2015, Monotypic prehistoric bird genera, so understanding it makes those chapters shorter.
In everyday life: Look for Stemec 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 Stemec in 20 minutes

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

Frequently asked questions

What is Stemec in simple terms?

Why does Stemec 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 Stemec?

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 Stemec.