Behaviour, development and life cycles
Follow changes through an organism's life and distinguish growth, development, inherited responses and learning.
What you will tackle
- Interpret animal behaviour evidence
- Distinguish growth from developmental change
- Sequence life cycles
- Connect plant structures with development and transport
Behaviour is evidence to explain
An innate response can develop without the specific learning experience being tested; learned behaviour changes through experience. Habituation is a reduced response after repeated harmless stimulation. A decrease in response can also reflect fatigue or sensory change, so comparisons are needed. Growth increases size or cell number; development changes organisation or function.
Life cycles and plant structure
A butterfly passes through egg, larva, pupa and adult; development includes major changes in form, not just greater mass. A flowering plant can pass through seed germination, vegetative growth, flowering, fertilisation and seed formation. Roots take up water and mineral ions; leaves exchange gases and often photosynthesise; xylem carries water and minerals, while phloem transports organic products between sources and sinks.
Build your notes, then practise
Work on paper before opening an explanation. Guided tasks provide a starting point; independent tasks remove the scaffolding; application tasks ask you to justify a method or interpretation in context.
Guided practice
Guided 1
Put butterfly stages adult, egg, pupa, larva into a life-cycle order. An animal's response to repeated harmless tapping falls from 8 to 2 units, but its response to a new stimulus stays 8. Which learning explanation is supported, and why is simple general fatigue less likely?
Show a starting hint
Distinguish an observation from the explanation proposed for it.
Compare with the explained answer
- One cycle is egg → larva → pupa → adult → reproduction and eggs.
- The reduced response to repeated harmless input is consistent with habituation.
- A strong response to a different stimulus weakens a general-fatigue explanation, though further controls may still be needed.
Answer / response criteria: Stage order as stated; evidence consistent with habituation, qualified by controls.
Independent practice
Independent 1
A tadpole gains mass while limbs develop. Identify a growth measure and a development measure. Sequence seed, flowering, germination and new seed formation. Predict the immediate transport problem if a plant's xylem is blocked.
Compare with the explained answer
- Mass is a growth measure; limb formation is a developmental change.
- Seed → germination → vegetative growth → flowering → fertilisation and new seed formation.
- Blocking xylem restricts water/mineral movement toward leaves; it does not directly demonstrate a block of every phloem pathway.
Answer / response criteria: Mass versus limb formation; plant sequence as stated; restricted water/mineral transport.
Application practice
Application 1
Two animal groups receive the same food and temperature; only one receives experience with a route. It later completes the route faster. Design a check distinguishing learning from a pre-existing group difference. A plant trial measures height alone: can it establish that flowering occurred sooner?
Compare with the explained answer
- Record baseline performance and assign comparable animals randomly to experience conditions where feasible.
- Compare change and repeat trials; route speed alone does not exclude prior differences without this design.
- Height is a growth measure, not a direct flowering-time measure. Record the date or developmental stage separately.
Answer / response criteria: Use baseline and controlled comparisons; height alone cannot establish flowering time.
What can you explain now?
Two animal groups receive the same food and temperature; only one receives experience with a route. It later completes the route faster. Design a check distinguishing learning from a pre-existing group difference. A plant trial measures height alone: can it establish that flowering occurred sooner?
Compare with the explanation
Use baseline and controlled comparisons; height alone cannot establish flowering time.
Explain the reasoning before comparing. This review records your self-assessment rather than an official score or mastery decision.
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Source and review status
Coverage follows the named requirements and examples in the 2026–2027 ACT test guide and subject descriptions. That guide explicitly does not list every possible topic. The broader coded College and Career Readiness Standards are also mapped to conceptual teaching and practice; this does not calibrate a learner to a score band. The separate scientific-background context list and reading-complexity rubric have their own stated limits.
Original teaching and explained self-check practice are available. Specialist review and difficulty calibration remain pending. Essays require self-check or teacher review and are not automatically marked or awarded official scores.
Official source specification / guide