biology

Projectile use by non-human organisms

Projectile use by non-human organisms 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 Projectile use by non-human organisms rather than just read about it. In short: Although projectiles are commonly used in human conflict, projectile use by organisms other than humans is relatively rare. However, some organisms are capable of using various different types of projectiles for defense or predation.

Key takeaways

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

Reference excerpt

Although projectiles are commonly used in human conflict, projectile use by organisms other than humans is relatively rare. However, some organisms are capable of using various different types of projectiles for defense or predation. Some invertebrates are able to spit or squirt out fluids and some vertebrates also use liquid projectiles. Solid projectiles are used by various species. Tarantulas, for example, may kick off barbed hairs and several mammals have been observed to throw objects such as sand, rocks, sticks and feces. Chameleons, frogs and some salamanders have tongues that act like tethered projectiles. The pistol shrimp may emit a powerful wave of bubbles. Some plants produce seed pods that explode when touched or may fire spore capsules.

Animals

Liquid projectiles

Most projectiles used by terrestrial animals are liquids. Among invertebrates there are a number of examples. Velvet worms can squirt out a slimy adhesive fluid from glands on the sides of their head, and use it to trap their prey. The spitting spiders Scytodes can spit a venomous sticky fluid that traps its victims and also poisons them. The bombardier beetle is unusual by using a violent exothermic chemical reaction to launch a boiling noxious chemical spray in a rapid burst of pulses from special glands in its abdomen, accompanied with a popping sound. The Anthia (oogpister beetle) will fire formic acid at attackers, probably extracting the formic acid from the ants that it eats. The devil-rider stick insects (Anisomorpha) can fire terpenes from glands on the metathorax that can cause an intense burning irritation of the eyes and mouth of potential predators. Some species of ants of the subfamily Formicinae, like wood ants and weaver ants, will spray acid at attackers. They will bite to cause a wound and spray acid directly into the wound. A type of planthopper of Madagascar is able to flick small balls of honeydew, this attracts day geckos that feed on the honeydew and whose presence may deter predators from approaching the sap-sucking insect. Termites of the subfamily Nasutitermitinae can project a sticky fluid from a nozzle on their heads. They can use this fontanellar gun accurately, over a range of many centimeters, even though the termite is blind, possibly using auditory or olfactory cues instead. A number of vertebrates also use liquid projectiles. The archerfish will squirt water from its mouth to dislodge invertebrates from overhanging branches. Some diptodactyline geckos can fire a black or pale yellow sticky fluid out of glands in their tail for a distance of about a meter, and with good aim. This fluid has a musky unpleasant odour and although it is not toxic it may discourage predators, in particular the big arthropods that prey on these geckos. Some species of horned lizards (Phrynosoma) can fire an aimed stream of blood from the corners of the eyes for a distance up to 3 ft to deter predators. The spitting cobra can squirt venom from forward-facing holes in its fangs. It aims for its victim's eyes, spitting up to 1.5 meters (5 ft). The venom may cause blindness. The Mangshan pitviper is also reported to spit venom. A bird that uses liquid projectiles in defense is the southern giant petrel which produces a stomach oil made up of wax esters and triglycerides that are stored in the proventriculus and can be projectile vomited on predators. Other petrels such as the fulmar can also squirt oils from their mouths as a defense. They can squirt oils with accuracy up to a distance of 1 to 2 meters (3.5 to 6.5 ft). The oil mats the feathers of birds together and destroys their waterproofing abilities, so oiled birds may die from chilling or drowning, although fulmars seem able to remove the oil from themselves by preening. Birds ranging from gulls to sea-eagles have died after being squirted by fulmars. Some species of penguin expel liquid feces in a projectile manner, to a distance of up to about 50 cm (20 in). They are believed to do this because during the brooding season, when penguins are sitting on their nests, they avoid leaving their nests and thereby leaving their eggs open to predation and thus to maintain a clean nest they evolved the ability to project their feces. Among mammals, skunks can eject a noxious fluid from their anal glands. It is not only foul smelling, but can cause skin irritation and, if it gets in the eyes, temporary blindness. When it feels threatened a camel will bring up their stomach contents, along with saliva, and project it out towards the threat to distract, surprise, or bother the threat.

Solid projectiles

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Projectile use by non-human organisms

Start with the simplest possible case. Write down what Projectile use by non-human organisms 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 Projectile use by non-human organisms 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 Projectile use by non-human organisms 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 Projectile use by non-human organisms

In research: Projectile use by non-human organisms 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 Projectile use by non-human organisms 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: Projectile use by non-human organisms is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ballistics, Ethology, so understanding it makes those chapters shorter.
In everyday life: Look for Projectile use by non-human organisms 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 Projectile use by non-human organisms in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Projectile use by non-human organisms 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 Projectile use by non-human organisms out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Projectile use by non-human organisms in simple terms?

Why does Projectile use by non-human organisms 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 Projectile use by non-human organisms?

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 Projectile use by non-human organisms.