Plants defend themselves in several ways
הוצג| English | משמעות |
|---|---|
| waxy cuticle/ˈwæksi ˈkjuːtɪkl/ | קוטיקולה שעוונית |
| herbivore/ˈhɜːbɪvɔː/ | צמחונאי |
What would explain this observation?
- Plants cannot simply run away from a feeding animal. Their barriers, chemicals and mechanical responses reduce damage in different ways.
Build the model
- Physical defences include cellulose cell walls, a tough waxy cuticle 蜡质角质层 on leaves and layers of dead cells around stems as bark.
- Bark can fall off, removing attached pathogens.
- These structures form barriers to entry or damage.
- Chemical defences include antibacterial substances and poisons that deter herbivores 食草动物.
- waxy cuticle: A protective waxy layer on a plant surface.
- herbivore: An animal that feeds on plants.
Which is a specified chemical defence?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Plants' chemical defences include antibacterial substances they synthesise themselves. White blood cells belong to animal immune systems, and resolving power is a microscope property.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Mechanical adaptations include thorns and hairs that discourage feeding, leaves that droop or curl when touched, and mimicry that can deter animals.
- Explain the consequence of each feature: a thorn affects contact or feeding, while an antibacterial substance affects bacteria.
- No single defence protects a plant against every threat.
In the lab: Observe teacher-approved plants or supplied images without touching unknown hairs, thorns, sap or berries. Classify each feature as physical, chemical or mechanical in the specification’s grouping, then write a feature → effect → protection explanation. A paper model can compare exposed and protected surfaces without using a real poison or provoking animal feeding.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: a fictional protected-leaf model records 6 damaged patches among 50 compared with 15 among 50 in an unprotected model.
- Damage proportions are 12% and 30%, a difference of 18 percentage points.
- The comparison supports protection under those rules, not a universal reduction for every plant defence.
Your turn: A fictional model has 8 damaged patches among 40. Calculate percentage damaged.
A fictional model has 8 damaged patches among 40. Calculate percentage damaged.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 20 %. Known: 8 damaged patches among 40. Use percentage = damaged / total x 100. Percentage = 8/40 x 100 = 20%. Comparing defences needs matched conditions, as the worked case shows.
Check the conclusion and its limits
- A waxy cuticle is a physical barrier and is not an antibody.
- Plants do not use the same white-blood-cell mechanisms as animals.
- A poisonous plant can harm people as well as herbivores, so classroom observation must not involve tasting or extracting its chemicals.
Not true: Plants defend themselves by producing white blood cells. Plants have no immune system of mobile cells; they rely on physical barriers (cuticle, bark), chemical poisons and local responses. White blood cells are animal structures.
- Physical defences include cellulose cell walls, a tough waxy cuticle on leaves and layers of dead cells around stems as bark.
- Mechanical adaptations include thorns and hairs that discourage feeding, leaves that droop or curl when touched, and mimicry that can deter animals.
- Watch for: A waxy cuticle is a physical barrier and is not an antibody.
Plants defend themselves by producing white blood cells.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Plants have no immune system of mobile cells; they rely on physical barriers (cuticle, bark), chemical poisons and local responses. White blood cells are animal structures.
A protective waxy layer on a plant surface: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
waxy cuticle means A protective waxy layer on a plant surface.