plant responses Flashcards
define stimulus
anything that causes a reaction in an organism or any of its parts
whats an animal stimulus
includes feeling pain/hunger, hearing a noise
whats a plant stimulus
light, gravity, temperatures
define response
the action pf a cell/organism as a result of a stimulus
give an example of an animal response
movement, production of enzymes and feeding
give an example of a plant response
growth, flowering
what is needed structurally for response
chemical/hormonal system (plants and animals), nerve and sense organ system, method of movement, immune system
what do plants depend on for their response
chemical co-ordination
define tropsim
a chenge in the growth of a plant in response to an external stimulus
define positive tropism
when the growth is towards the stimulus
define negative tropism
when the growth is away from the stimulus
what is the advantage of tropisms in a plant
they allow plants to obtain favourable growing contidtions
what is phototropism
change in growth in a plant in response to light
are stems positively phototropic
yes… allows the plant to get more sunlight
are roots positively phototropic or negatively phototropic
most are neg… e.g ivyy
what is geotropism
the change in growth of a plant in response to gravity
are roots positively geotrophic
yes, they grow downwards
are stems positvely geotrophic
no they are negatively geotrophic… grow against gravity