Orientation in Space
What is a Tropism?
A directional plant growth response toward or away from a stimulus.
What is a circadian rhythm?
A biological rhythm that repeats roughly every 24 hours.
What is territoriality?
Defence of an area by an individual or group against others of the same species
What is mutualism?
A relationship where both species benefit.
What is innate behaviour?
A behaviour that is inherited and not learned.
What plant hormone controls phototropism?
Auxin
What is a zeitgeber?
An external cue (like light) that resets an organism’s biological clock.
What is a pecking order?
A social hierarchy determining dominance and access to resources.
Give an example of commensalism.
Barnacles on whales benefit from transport; whales are unaffected.
What is learning?
Behaviour modified by experience.
What is the difference between taxis and kinesis?
Taxis is directional movement toward/away from a stimulus; kinesis is non-directional movement where activity depends on stimulus intensity.
What is the difference between endogenous and exogenous rhythms?
Endogenous rhythms are internally controlled. Exogenous rhythms rely on external cues
How does courtship behaviour improve reproductive success?
It ensures species recognition and synchronises mating readiness.
What is Batesian mimicry?
When a harmless species mimics a harmful one.
Why is migration considered an adaptive behaviour?
It allows access to better resources, breeding sites, or climates, improving survival and reproduction.
Give one example of how animals use celestial cues to navigate.
Birds use the sun (solar navigation) or stars (stellar navigation) to migrate
What is photoperiodism?
The physiological response of plants to the length of day and night.
How do pheromones help within a species?
They communicate signals like mating readiness or territory marking.
What is the main difference between interspecific and intraspecific competition?
Interspecific is between different species; intraspecific is within one species.
How does having a specific ecological niche reduce competition?
It minimises overlap in resource use between species.
Explain how auxin distribution leads to phototropism.
When a plant is exposed to light from one side, the auxin hormone redistributes to the shaded side of the stem. This uneven distribution causes the cells on the shaded side to elongate faster than those on the lit side, resulting in the stem bending and growing towards the light source
How does phytochrome help plants measure day length?
Phytochrome switches between active/inactive forms depending on light wavelengths, allowing plants to detect day length and trigger flowering
How does group cooperation benefit hunting species?
Increases hunting success and allows larger prey capture or efficient energy use.
How do prey avoid predators? Give two strategies.
Camouflage, mimicry, fleeing, grouping, or chemical defences.
Explain the adaptive advantage of tropisms and nastic responses.
They allow plants to maximise resources (light, water) and protect themselves, enhancing survival and reproduction.