science

Mrs. Ples

Mrs. Ples 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 Mrs. Ples rather than just read about it. In short: Mrs. Ples is the popular nickname for the most complete skull of an Australopithecus africanus ever found in South Africa.

Key takeaways

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

Reference excerpt

Mrs. Ples is the popular nickname for the most complete skull of an Australopithecus africanus ever found in South Africa. Many Australopithecus fossils have been found near Sterkfontein, about 40 kilometres (25 mi) northwest of Johannesburg, in a region of Gauteng (part of the old Transvaal) now designated as the Cradle of Humankind World Heritage Site. Mrs. Ples was discovered by Robert Broom and John T. Robinson on April 18, 1947. Because of Broom's use of dynamite and pickaxe while excavating, Mrs. Ples's skull was blown into pieces and some fragments are missing. Nonetheless, Mrs./Mr. Ples is one of the most "perfect" pre-human skulls ever found. The skull is currently held at the Ditsong National Museum of Natural History in Pretoria.

The nickname "Mrs. Ples" was coined by Broom's young co-workers. It derives from the scientific name Plesianthropus transvaalensis (near-man from the Transvaal), that Broom initially gave the skull, later subsumed (synonymized) into the species Australopithecus africanus. In scientific publications, the specimen is referred to by its catalogue number, STS 5. The genus Australopithecus, of which there are several species, is considered the likely precursor of the genus Homo. Though its cranium is comparable to a chimpanzee's, Australopithecus walked upright, as humans do. This was a surprise to anthropologists at the time, because it had been assumed that the big brain of Homo had preceded, or at least evolved in tandem with, our upright gait. Mrs. Ples, whose cranial capacity is only about 485 cubic centimetres (29.6 cubic inches), was one of the first fossils to reveal that upright walking had evolved well before any significant growth in brain size. The sex of the specimen is not completely certain and so Mrs. Ples may in fact be Mr. Ples. Moreover, X-ray analysis of the specimen's teeth (see below) has suggested it was an adolescent. Hence a designation of Miss Ples or Master Ples is also possible. The paleoanthropologist Prof. Frederick E. Grine has studied the dental morphology of Mrs./Mr. Ples with a view to finally establishing Mrs./Ms. Ples's sex. Using the Computed Tomography (CT) scans of STS 5 from the experiments of Weber et al., (2012) they compared them to CT scans of more recently discovered A. africanus skulls from Sterkfontein. These scans allowed Grine to reconstruct the roots of the teeth, in order to see how the molar and canine teeth developed. This study concluded that Mrs./Mr. Ples was indeed a middle-aged female. However, the question is not entirely settled, since other studies have come to the opposite conclusion. Some experts have suggested that a partial skeleton, known only by its catalogue number of STS 14, which was discovered in the same year, in the same geological deposit and in proximity to Mrs. Ples, may belong to this skull. If correct, this would make Mrs. Ples the South African counterpart to the famous Lucy fossil. This skull, along with others discovered at Taung, Sterkfontein, and Makapansgat offered compelling evidence in favour of Charles Darwin's hypothesis that humanity's origin lay in Africa. The fossil was originally dated by a combination of palaeomagnetism and uranium-lead techniques to 2.1-2.6 million years ago. A 2022 study dating surrounding rocks with a new methodology, stated their age as 3.4-3.7 million years old. In 2004, Mrs. Ples was voted 95th in the SABC 3's and e.tv's Great South Africans Top 100 list.

See also List of human evolution fossils Taung Child

References

Illustrations

Worked examples

Example 1 — a first encounter with Mrs. Ples

Start with the simplest possible case. Write down what Mrs. Ples 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 Mrs. Ples 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 Mrs. Ples 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 Mrs. Ples

In research: Mrs. Ples 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 Mrs. Ples 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: Mrs. Ples is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1947 in paleontology, Archaeology of South Africa, Australopithecus fossils, so understanding it makes those chapters shorter.
In everyday life: Look for Mrs. Ples 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 Mrs. Ples in 20 minutes

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

Frequently asked questions

What is Mrs. Ples in simple terms?

Mrs. Ples is the popular nickname for the most complete skull of an Australopithecus africanus ever found in South Africa.

Why does Mrs. Ples 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 Mrs. Ples?

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 Mrs. Ples.