science

Passerae

Passerae is a science 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 Passerae rather than just read about it. In short: The "Passerae" were a proposed "parvclass" of birds in the Sibley–Ahlquist taxonomy. This taxon is a variation on the theme of "near passerines", birds that were – and often still are – believed to be close relatives of the passerines (perching birds, which include the songbirds).

Key takeaways

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

Reference excerpt

The "Passerae" were a proposed "parvclass" of birds in the Sibley–Ahlquist taxonomy. This taxon is a variation on the theme of "near passerines", birds that were – and often still are – believed to be close relatives of the passerines (perching birds, which include the songbirds). This proposed taxon was roundly rejected by subsequent cladistic analyses. According to Sibley and Ahlquist, they include the following superorders and orders:

Superorder Cuculimorphae Order Cuculiformes Superorder Psittacimorphae Order Psittaciformes Superorder Apodimorphae Order Apodiformes Order Trochiliformes Superorder Strigimorphae Order Musophagiformes Order Strigiformes Superorder Passerimorphae Order Columbiformes Order Gruiformes Order Ciconiiformes Order Passeriformes Notable orders traditionally considered "near passerines" but not placed in the Passerae of the Sibley–Ahlquist taxonomy are Coliiformes, Coraciiformes, Piciformes and Trogoniformes (see below for why this is significant). While the Sibley–Ahlquist taxonomy certainly represents a monumental endeavour and has some strong points (namely the recognition of the Galloanserae), basically everything about this "parvclass" is today regarded as utter fiction, brought about by the methodological and analytical problems of the phenetic DNA–DNA hybridization analysis. The "Passerae" are one of the most seriously flawed systematic proposals in modern ornithology, perhaps rivalled only by the suggestion (based as it was on early cladistic analyses) that Hesperornithes, Gaviiformes and Podicipediformes form a monophyletic group. In sheer scope of their falseness, however, the "Passerae" are in post-Linnean ornithology matched only by the ecomorphology-based "taxa" of Charles Lucien Jules Laurent Bonaparte's mid-19th century Conspectus Generum Avium.

Refutation Subsequent studies consider none of the orders contained in the "Passerae" particularly close to the passerines. And with the possible exception of the Columbiformes, about whose evolutionary history next to nothing is known as of 2007, all the "Passerimorphae" are universally considered to be about as far from the Passeriformes as a neoavian can possibly be. The all-encompassing "Ciconiiformes" are rejected by modern science, as is the grouping of owls and nightjars to the exclusion of swifts and hummingbirds, which moreover are not so distantly related to justify treatment as distinct orders. The close relationship of Musophagiformes and owls, while neither of the two groups is firmly placed in avian systematics, is also highly suspect. At present, the closest living relatives of passerines are held to be the Piciformes, followed by the Coraciiformes. Neither of these two was included in the "Passerae". The Coliiformes and Trogoniformes, while of unclear relationships among the "higher landbirds", are also candidates for inclusion in a "near passerine" superorder. Insofar, it is actually hard to be less correct regarding the relationships of the perching birds than the Sibley–Ahlquist taxonomy. Parvclasses are generally not used at all in modern ornithological systematics, as the understanding of neoavian relationship has not progressed to a point where use of such a taxonomic rank would seem sensible.

Footnotes

References Cracraft, Joel (1982): Phylogenetic relationships and monophyly of loons, grebes, and hesperornithiform birds, with comments on the early history of birds. Systematic Zoology 31: 35–56. doi:10.2307/2413412 (HTML abstract) Mindell, David P.; Brown, Joseph W. & Harshman, John (2005): The Tree of Life Web Project - Neoaves. Version of 2005-DEC-14. Retrieved 2008-JAN-08.

Worked examples

Example 1 — a first encounter with Passerae

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

In research: Passerae appears in science 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 Passerae 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: Passerae is common in secondary-school and first-year university syllabi. It links to neighbouring topics Obsolete bird taxa, so understanding it makes those chapters shorter.
In everyday life: Look for Passerae 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 Passerae in 20 minutes

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

Frequently asked questions

What is Passerae in simple terms?

Why does Passerae matter?

Because it connects several science 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 Passerae?

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 Passerae.