chemistry

Miacidae

Miacidae is a chemistry 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 Miacidae rather than just read about it. In short: Miacidae ("small points") is a former paraphyletic family of extinct primitive placental mammals that lived in North America, Europe and Asia during the Paleocene and Eocene epochs, about 65–33.9 million years ago. These mammals were basal to order Carnivora, the crown-group within the Carnivoraformes.

Key takeaways

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

Reference excerpt

Miacidae ("small points") is a former paraphyletic family of extinct primitive placental mammals that lived in North America, Europe and Asia during the Paleocene and Eocene epochs, about 65–33.9 million years ago. These mammals were basal to order Carnivora, the crown-group within the Carnivoraformes. Miacids are thought to have evolved into the modern carnivorous mammals of the order Carnivora. They were small carnivores, superficially weasel-like or ferret-like with long, lithe bodies and long tails. Some species were arboreal, while others lived on the ground. They probably fed on invertebrates, lizards, birds, and smaller mammals like shrews and opossums. Their teeth and skulls show that the miacids were less developed than modern carnivorans. They had carnivoran-type carnassials, but lacked fully ossified auditory bullae (rounded protrusions).

Classification

History of classification Miacidae as traditionally conceived is not a monophyletic group; it is a paraphyletic array of stem taxa. Traditionally, Miacidae and Viverravidae had been classified in a superfamily, Miacoidea. Today, Carnivora and Miacoidea are grouped together in the crown-clade Carnivoramorpha, and the Miacoidea are regarded as basal carnivoramorphs. Some species of the genus Miacis are closely related to the order Carnivora, but only the species Miacis australis and Miacis cognitus are true carnivorans, as they are classified in the family Amphicyonidae within Caniformia. The divergence of carnivorans from miacids is now inferred to have occurred in the middle Eocene (c. 42 million years ago). Traditionally, the Viverravidae (viverravids) had been thought to be the earliest carnivorans, with fossil records first appearing in the Paleocene of North America about 66 million years ago, but recent cranial morphology evidence now places them outside the order Carnivora. Later authorities disagreed, and propose that the viverravids arose in North America 66-60 million years ago, spread to Asia then later to Europe, and were the first carnivorans and possessed the first true pair of carnassial teeth. It has been proposed that miacids arose in North America and Europe 60-50 million years ago then later spread to Asia. Like the earlier viverravids, they possessed a true pair of carnassial teeth and therefore are related to order Carnivora. They also possessed a full set of cheek teeth, were weasel-to-small-fox-sized, and lived in forests. All modern carnivorans arose from them.

Taxonomy Family: †Miacidae (Cope, 1880) Genus: †Chailicyon (Chow, 1975) Genus: †Eogale (Beard & Dawson, 2009) Genus: †Gracilocyon (Smith & Smith, 2010) Genus: †Harpalodon (Marsh, 1872) Genus: †Lycarion (Matthew, 1909) Genus: †Messelogale (Springhorn, 2000) Genus: †Miacis (Cope, 1872) Genus: †Miocyon (Matthew, 1909) Genus: †Neovulpavus (Wortman, 1901) Genus: †Oodectes (Wortman, 1901) Genus: †Palaearctonyx (Matthew, 1909) Genus: †Paramiacis (Mathis, 1985) Genus: †Paroodectes (Springhorn, 1980) Genus: †Procynodictis (Wortman & Matthew, 1899) Genus: †Prodaphaenus (Wortman & Matthew, 1899) Genus: †Quercygale (Kretzoi, 1945) Genus: †Simamphicyon (Viret, 1942) Genus: †Tapocyon (Stock, 1934) Genus: †Uintacyon (Leidy, 1872) Genus: †Vassacyon (Matthew, 1909) Genus: †Vulpavus (Marsh, 1871) Genus: †Xinyuictis (Zheng, 1975) Genus: †Zodiocyon (Tong & Wang, 2006)

Phylogeny

References

Illustrations

Worked examples

Example 1 — a first encounter with Miacidae

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

In research: Miacidae appears in chemistry 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 Miacidae 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: Miacidae is common in secondary-school and first-year university syllabi. It links to neighbouring topics Obsolete mammal taxa, Taxa named by Edward Drinker Cope, so understanding it makes those chapters shorter.
In everyday life: Look for Miacidae 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 Miacidae in 20 minutes

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

Frequently asked questions

What is Miacidae in simple terms?

Why does Miacidae matter?

Because it connects several chemistry 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 Miacidae?

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 Miacidae.