biology

Physetocaris

Physetocaris 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 Physetocaris rather than just read about it. In short: Physetocaris is a monotypic genus of caridean shrimp, containing a single species, Physetocaris microphthalma. Systematics Physetocaris microphthalma was previously placed in its own family (Physetocarididae) and superfamily (Physetocaridoidea).

Key takeaways

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

Reference excerpt

Physetocaris is a monotypic genus of caridean shrimp, containing a single species, Physetocaris microphthalma.

Systematics Physetocaris microphthalma was previously placed in its own family (Physetocarididae) and superfamily (Physetocaridoidea). Molecular phylogenetic analysis has revealed that the species actually belongs within the family (Pandalidae) and superfamily (Pandaloidea). The genus and species were described in 1940 by Fenner A. Chace Jr.

Description Adults have no eyes, and are missing the last segment of the first pereiopod, which is therefore unable to form a claw. They also have reduced gills and mouthparts, and no exopods on the pereiopods. The carapace is enlarged, and forms a tall rostrum.

Distribution P. microphthalma is rare, with only 35 specimens counted in a 1985 review. Although very poorly known, the distribution of Physetocaris appears to be very wide. In addition to specimens from both western and eastern parts of the Atlantic Ocean, it has been found in the southern Pacific Ocean.

References

Worked examples

Example 1 — a first encounter with Physetocaris

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

In research: Physetocaris 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 Physetocaris 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: Physetocaris is common in secondary-school and first-year university syllabi. It links to neighbouring topics Caridea, Monotypic decapod genera, so understanding it makes those chapters shorter.
In everyday life: Look for Physetocaris 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 Physetocaris in 20 minutes

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

Frequently asked questions

What is Physetocaris in simple terms?

Physetocaris is a monotypic genus of caridean shrimp, containing a single species, Physetocaris microphthalma. Systematics Physetocaris microphthalma was previously placed in its own family (Physetocarididae) and superfamily (Physetocaridoidea).

Why does Physetocaris 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 Physetocaris?

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 Physetocaris.