Brent Cornell

    
A behaviour is typically defined as any observable action by a living organisms

• Behaviours can be categorised as either innate or learned

An innate behaviour is an instinctive response that is developmentally fixed – it is independent of environmental context

• Innate behaviours have a genetic basis and are hence inherited from parents

    
Any instinctive response that improves survival and reproductive prospects will become more common by natural selection

• Examples of innate behavioural responses seen in invertebrates include taxis and kinesis

Taxis

Taxis is a change in movement in response to an environmental stimulus – either towards (positive) or away (negative)

Euglena is a photosynthetic microorganism that requires light as an energy source and hence displays positive phototaxis

• Step 1:  Place Euglena in a petri dish with appropriate environmental conditions for survival
• Step 2:  Cover the dish with aluminium foil, excluding a few small exposed sections
• Observation:  With a light source placed above the dish, the Euglena should migrate towards the exposed sections

Kinesis

Kinesis is a change in the rate of activity in response to an environmental stimulus

Woodlice have gills for respiration and tend to prefer moist conditions (their gills may dry out in dry conditions)

• Step 1:  Place a woodlouse in a dry petri dish and mark its movements every 30 seconds
• Step 2:  Repeat this process for a second woodlouse placed in moist conditions (i.e. petri dish lined with wet paper towel)
• Observation:  The woodlouse in dry conditions should have a higher rate of movement (improve chances of finding moisture)