biology

Ontogenetic depth

Ontogenetic depth 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 Ontogenetic depth rather than just read about it. In short: Ontogenetic depth is a pseudoscientific idea proposed in February 2003 by Paul Nelson, an American philosopher of science, young Earth creationist and intelligent design advocate; he is employed by the Discovery Institute. Basically, Nelson concludes in his 'hypothesis' that developmental complexity is unbreakable, and that if he shows Cambrian organisms to be complex, then it is therefore impossible for them to hav…

Key takeaways

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

Reference excerpt

Ontogenetic depth is a pseudoscientific idea proposed in February 2003 by Paul Nelson, an American philosopher of science, young Earth creationist and intelligent design advocate; he is employed by the Discovery Institute. Basically, Nelson concludes in his 'hypothesis' that developmental complexity is unbreakable, and that if he shows Cambrian organisms to be complex, then it is therefore impossible for them to have evolved. Nelson proposes 'ontogenetic depth' as evidence of specified complexity, and a reliable marker of design by an intelligent agent, in opposition to modern evolutionary theory. Nelson subsequently stated that ontogenetic depth is "Currently Impossible to Measure".

Criticism Biologist PZ Myers, who works in the field of evolutionary developmental biology, dismissed the concept, stating in 2010 that "Nelson is a creationist who made up this wacky claim of "ontogenetic depth", saying he had a way of objectively measuring the complexity of the developmental process in organisms with a number that described the distance from egg to adult. Unfortunately, he forgot to tell us how one calculated this number, or how it actually accounted for the complexity of a network, or even how we'd get a number that was different for a sponge and a cat. But he did say he'd get back to us with the details tomorrow...six years ago." Myers concludes that "ontogenetic depth is a sloppily-defined concept with no theoretical support for its validity and no apparent operational utility." The concept of 'ontogenetic depth' has not been published in any peer-reviewed journal, there are no methods described that would allow to measure this value in any organisms, nobody other than Nelson and his collaborator, Marcus Ross, do anything with the idea.

References

External links Nelson, Paul (April 6, 2011). "Understanding Ontogenetic Depth, Part I: Naming Versus Measuring". Evolution News. Retrieved 23 February 2024. Nelson, Paul (April 7, 2011). "Understanding Ontogenetic Depth, Part II: Natural Selection Is a Harsh Mistress". Evolution News. Retrieved 23 February 2024.

Worked examples

Example 1 — a first encounter with Ontogenetic depth

Start with the simplest possible case. Write down what Ontogenetic depth 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 Ontogenetic depth 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 Ontogenetic depth 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 Ontogenetic depth

In research: Ontogenetic depth 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 Ontogenetic depth 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: Ontogenetic depth is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arguments for the existence of God, Creationism stubs, Creationist objections to evolution, so understanding it makes those chapters shorter.
In everyday life: Look for Ontogenetic depth 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 Ontogenetic depth in 20 minutes

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

Frequently asked questions

What is Ontogenetic depth in simple terms?

Why does Ontogenetic depth 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 Ontogenetic depth?

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 Ontogenetic depth.