For this IBDP Biology blog post, we will be looking at examples of two ways animal responses can be affected, as well as the diverse range of the different stimulus and reactions towards it.
Explain how animal responses can be affected
Migration in Sylvia atricapilla, or blackcaps
- This bird specie breeds in early summer across much of central and northern Europe, and then migrates in the fall.
- Recently, 10% of blackcaps migrate to the UK. Experiments with eggs have shown that the direction of migration is genetically programmed and inherited.
- Blackcaps that migrate from Germany to the UK instinctively fly west.
- Blackcaps that migrate from Germany to Spain instinctively fly southwest.
Timing of breeding in Parus major
- Parus major breeds in spring or early summer throughout much of Europe.
- Timing of egg laying is genetically influenced; day length is used to determine the time of year.
Recent studies of birds in the Netherlands have shown:
- date of egg laying is becoming earlier
- adults that breed earlier have greater reproductive success due to earlier opening of leaves on deciduous trees
- earlier peak in biomass of invertebrates feeding on tree leaves
- invertebrates = main food adults collect and feed to offspring
The diversity of stimuli
Mechanoreceptors: Mechanical energy in the form of sound waves. Movements due to pressure or gravity. --> Hair cells in the cochlea of the ear. Pressure receptor cells in the skin.
Chemoreceptor: Chemical substances dissolved in water (tongue). Chemical substances as vapours in the air (nose) --> receptor cells in the tongue. Nerve endings in the nose. (Hypothalamus in brain)
Thermoreceptors: Temperature --> Nerve endings in the skin detect warm or cold.
Photoreceptors: Electromagnetic radiation, usually in the form of light. --> Rod and cone cells in the eye.
That is all!
References
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.shutterstock.com%2Fsearch%2Fmechanoreceptors&psig=AOvVaw1rKhj_pd0mIeRhlia_Lwqm&ust=1627289106867000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCJjs7Lvq_fECFQAAAAAdAAAAABAn
- https://www.google.com/url?sa=i&url=http%3A%2F%2Fib.bioninja.com.au%2Foptions%2Foption-a-neurobiology-and%2Fa6-ethology%2Fmigration.html&psig=AOvVaw2C4Eez0p2C8pkShyWThRRc&ust=1627289209388000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCOja4ezq_fECFQAAAAAdAAAAABAD
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.shutterstock.com%2Fimage-photo%2Fgreat-tit-parus-major-titmouse-oxeye-172569815&psig=AOvVaw3wO3XrT_1BobRCAlSGdLIb&ust=1627289261351000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCLC17oXr_fECFQAAAAAdAAAAABAD
Drafted by Venetia (Biology)