biology

Puijila

Puijila 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 Puijila rather than just read about it. In short: Puijila darwini is an extinct species of stem-pinniped (seal) which lived during the Miocene about 21 to 24 million years ago. About a metre (3 feet) long, the animal had only minimal physical adaptations for swimming.

Key takeaways

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

Reference excerpt

Puijila darwini is an extinct species of stem-pinniped (seal) which lived during the Miocene about 21 to 24 million years ago. About a metre (3 feet) long, the animal had only minimal physical adaptations for swimming. Unlike modern pinnipeds, it did not have flippers and its shape was otter-like, albeit more specialized; its skull and teeth are the features that most clearly indicate that it is a seal. It is considered to be the most primitive pinnipedimorph yet found. The genus name is an Inuktitut word for a young seal; the species name honours Charles Darwin. The holotype and only known specimen is a nearly complete fossil skeleton found in the Haughton Formation on Devon Island in the high Canadian Arctic. It is housed at the Canadian Museum of Nature, Ottawa, Ontario.

Background Puijila darwini was a semi-aquatic carnivore which represents a morphological link in early pinniped evolution. Its fossil shows enlarged, probably webbed feet, robust forelimbs and an unspecialized tail. This suggests that Puijila swam quadrupedally using its webbed fore and hind feet for propulsion. Phylogenetic studies including molecular evidence suggest a sister relationship between seals, bears and musteloids (weasels and otters). It had been popularly assumed that land mammals at some point transitioned to being more marine, in essence "returning to the sea" in order to gain some sort of survival advantage. However, fossil evidence of this transition had been weak or contentious. The discovery of Puijila is important as it represents a morphological link in early seal evolution, and one that appears to morphologically precede the more familiarly structured genus Enaliarctos, despite apparently being a younger genus. In other words, Puijila is a transitional fossil that provides information about how the seals returned to the sea, similar to how Archaeopteryx illuminates the origin of birds.

Discovery This novel species was discovered in 2007 by Natalia Rybczynski and her team using surface collection and screening at an early Miocene lake deposit of the Haughton Formation of Devon Island, Nunavut, Canada. The paleobotanical record suggests that the paleoenvironment around the lake comprised a forest community transitional between a boreal and a conifer–hardwood forest, in a cool temperate, coastal climate with moderate winters. Puijila darwini is the first mammalian carnivore found in the Haughton lake deposits. This is also an indication that the entire pinniped clade may have originated in the Arctic. The initial find is credited to field assistant Elizabeth Ross, and was partly a matter of luck. Ross had been unexpectedly stranded with the team's ATV which had run out of fuel several kilometers from base camp. The brain case was discovered a year later on the first day of the 2008 field expedition by Martin Lipman, the team's photographer.

References

External links

Natalia Rybczynski at the Canadian Museum of Nature Brian Switek, Puijila darwini: A Significant Seal. Robert Boessenecker, Puijila, a very basal 'pinnipedimorph'. Ed Yong, Puijila, the walking seal — a beautiful transitional fossil. "Fossil seal had the feet of an otter" by Bob Holmes, New Scientist, 25 April 2009, p. 10.

Illustrations

Worked examples

Example 1 — a first encounter with Puijila

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

In research: Puijila 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 Puijila 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: Puijila is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aquitanian genus extinctions, Chattian genus first appearances, Fossil taxa described in 2009, so understanding it makes those chapters shorter.
In everyday life: Look for Puijila 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 Puijila in 20 minutes

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

Frequently asked questions

What is Puijila in simple terms?

Why does Puijila 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 Puijila?

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 Puijila.