biology

Sexual characteristics

Sexual characteristics 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 Sexual characteristics rather than just read about it. In short: Sexual characteristics are physical traits of an organism (typically of a sexually dimorphic organism) which are indicative of or resultant from biological sexual factors. These include both primary sex characteristics, such as gonads, and secondary sex characteristics.

Key takeaways

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

Reference excerpt

Sexual characteristics are physical traits of an organism (typically of a sexually dimorphic organism) which are indicative of or resultant from biological sexual factors. These include both primary sex characteristics, such as gonads, and secondary sex characteristics.

Humans

In humans, sex organs or primary sexual characteristics, which are those a person is born with, can be distinguished from secondary sex characteristics, which develop later in life, usually during puberty. The development of both is controlled by sex hormones produced by the body after the initial fetal stage where the presence or absence of the Y-chromosome and/or the SRY gene determine development. Male primary sex characteristics are the penis, the scrotum and the ability to ejaculate when matured. Female primary sex characteristics are the vulva, vagina, uterus, uterine tubes, cervix, and the ability to give birth and menstruate when matured. Hormones that express sexual differentiation in humans include:

estrogens such as estradiol progestogens such as progesterone androgens such as testosterone The following table lists the typical sexual characteristics in humans (even though some of these can also appear in other animals as well):

Other organisms In invertebrates and plants, hermaphrodites (which have both male and female reproductive organs either at the same time or during their life cycle) are common, and in many cases, the norm. In other varieties of multicellular life (e.g. the fungi division, Basidiomycota), sexual characteristics can be much more complex, and may involve many more than two sexes. For details on the sexual characteristics of fungi, see: Hypha and Plasmogamy. Secondary sex characteristics in non-human animals include manes of male lions, long tail feathers of male peafowl, the tusks of male narwhals, enlarged proboscises in male elephant seals and proboscis monkeys, the bright facial and rump coloration of male mandrills, and horns in many goats and antelopes.

See also Mammalian gestation Reproduction Sex and gender distinction Sexual differentiation

References

Worked examples

Example 1 — a first encounter with Sexual characteristics

Start with the simplest possible case. Write down what Sexual characteristics 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 Sexual characteristics 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 Sexual characteristics 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 Sexual characteristics

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

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

Frequently asked questions

What is Sexual characteristics in simple terms?

Why does Sexual characteristics 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 Sexual characteristics?

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 Sexual characteristics.