biology

Isurus planus

Isurus planus 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 Isurus planus rather than just read about it. In short: Isurus planus is an extinct shark belonging to the Lamnidae family of the Miocene epoch. It has curved teeth without lateral protrusions, and aside from this, it is similar to mako shark.

Key takeaways

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

Reference excerpt

Isurus planus is an extinct shark belonging to the Lamnidae family of the Miocene epoch. It has curved teeth without lateral protrusions, and aside from this, it is similar to mako shark. The tooth length of I. planus reaches up to 4.8 cm (1.9 in). This suggests that I. planus was a large predatory shark similar to the modern mako shark.

Description I. planus lived throughout the entire Miocene epoch, from the earliest to the latest stage. It reached a maximum body length of about 3.2–3.6 m (10–12 ft). Its tooth roots are uneven in thickness and shape, with narrow builds and rounder lobes. The crowns of the lower teeth of this species are described to be more straight and identical to the lower teeth of C. hastalis.The hooked teeth, which probably would be efficient for gripping prey, would suggest a diet of smaller and medium-sized animals.

Paleobiology I. planus is presumed to have preferred a diet similar to that of extant mako shark. The shape of its teeth is small, fast, and structured to catch slippery prey. This suggests that it primarily fed on small to medium-sized fish. It is also possible that it preyed on dolphins or pinnipeds smaller than itself.

Illustrations

Worked examples

Example 1 — a first encounter with Isurus planus

Start with the simplest possible case. Write down what Isurus planus 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 Isurus planus 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 Isurus planus 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 Isurus planus

In research: Isurus planus 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 Isurus planus 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: Isurus planus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chondrichthyes stubs, Fossil taxa described in 1839, Fossils of Argentina, so understanding it makes those chapters shorter.
In everyday life: Look for Isurus planus 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 Isurus planus in 20 minutes

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

Frequently asked questions

What is Isurus planus in simple terms?

Isurus planus is an extinct shark belonging to the Lamnidae family of the Miocene epoch. It has curved teeth without lateral protrusions, and aside from this, it is similar to mako shark.

Why does Isurus planus 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 Isurus planus?

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 Isurus planus.