2.10.4Inquiry Process
Nutrition: Adaptations of Organisms — IB Biology HL Revision Notes & Topical Questions
5 min read 5 parts Lesson 99 of 160
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 5Adaptations for Herbivory
Plant tissue is tough and low in nutrients, so herbivores show specialised feeding structures and digestion.
Aphid stylets
- Aphid stylets Aphids pierce plant tissue with needle-like mouthparts and feed on the sugary sap in phloem.
Mandibles
- Mandibles Caterpillars, grasshoppers and beetles have strong mouthparts that cut and chew leaf tissue.
Grinding teeth
- Grinding teeth Grazing mammals such as sheep and horses have flat teeth that grind fibrous plant matter.
Ruminant digestion
- Ruminant digestion Cattle and deer have multi-chambered stomachs and re-chew food, and gut microorganisms with cellulase digest cellulose.
| Group | Adaptation | Benefit |
|---|---|---|
| Aphids | Stylets | Reach phloem sap |
| Caterpillars | Mandibles | Cut leaves |
| Ruminants | Gut microbes | Digest cellulose |
Section 2 of 5Plant Defences
Plants cannot flee, so they rely on mechanical and chemical defences.
Plant Defences
Spines and hairs
- Spines and hairs Cacti have spines and nettles have stinging hairs, which physically deter animals from feeding.
Toxic compounds
- Toxic compounds Foxglove makes digitalis and deadly nightshade makes atropine, poisons that affect heart and nerves.
Tannins
- Tannins These bitter chemicals deter feeding and reduce the efficiency of digestion in animals that eat the plant.
Alkaloids
- Alkaloids Caffeine and nicotine are toxic to many insects and so protect leaves from being eaten.
Section 3 of 5Predator Adaptations
Sensory structures
- Sensory structures Forward-facing eyes give overlapping vision and good depth judgement for locating prey.
Capture tools
- Capture tools Claws, sharp teeth and venom help predators seize and kill their prey.
Speed and stealth
- Speed and stealth Fast movement, quiet approach or ambush behaviour lets predators get close before attack.
Camouflage
- Camouflage Body colouring that matches the background lets predators avoid detection by prey.
Section 4 of 5Prey Adaptations
1
Eyes placed on the sides of the head give prey a wide field of view to detect predators early.
2
Camouflage or disruptive patterns make prey harder to see against the background.
3
Warning colours advertise toxicity or a nasty taste so predators learn to avoid them.
4
Speed, agility and herding behaviour help prey escape or reduce the chance an individual is caught.
5
Defences such as spines, armour or chemical sprays raise the cost of attacking.
Section 5 of 5Exam Checklist & Tips
2.10.4 – Key Points for the Exam
- Adaptation A characteristic that increases an organism's chance of survival and reproduction in its environment.
- Herbivory Feeding on plant tissues.
- Secondary compound A chemical not needed for basic metabolism, often a defence, such as tannin or atropine.
- Predator An animal that hunts and kills other animals for food.
- Prey An animal that is hunted and eaten by a predator.
Common Mistakes
- Saying herbivores digest cellulose themselves; gut microorganisms provide the enzyme.
- Describing adaptations as changes that individuals make during their lifetime.
- Forgetting to link each adaptation to its advantage for survival.
- Mixing up predator eye position with that of prey; predators usually face forward.
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