homeostasis and behavior Flashcards
what is behavior?
a stimulus is anything that causes a reaction or change in an organism (e.g. temperature)
a response is an organism’s reaction to a stimulus.
a behavior is a set of actions taken by an organism in response to stimulus.
though an organism’s outside environment may change, homeostasis is maintaining a stable balance in the body.
how are stimuli detected?
through sensory receptors found in sensory organs (eyes, tongue, nose, ears, whiskers, etc.)
how do organisms respond to stimuli?
animals send messages along the nervous system to the brain when they detect stimuli.
the brain interprets the sensory information and sends signals along the nerves to tell the body how to respond.
plants have electrical signals as well.
hormones can also cause responses. a hormone is a chemical signal produced in one part of an organism that affect cell activity in another part of the organism.
hormones are slower than electrical signals.
a given response may be effected by both hormones and electrical signals.
what are external stimuli?
an external stimulus is any stimulus that comes from outside the body of an organism and that influences the behavior of the organism.
taxi’s is the movement of organisms toward (+ve taxis) or away (-ve taxis) from an external stimulus.
tropism is the movement of a plant in response to an external stimulus, such as light (phototropism) or gravity (geotropism).
what are internal stimuli?
an internal stimulus is a stimulus that comes from inside an organism’s body. examples include: hunger, thirst, sickness.
some responses to internal stimuli are controlled by hormones. hormones, in animals, are released into the blood stream by the endocrine system.
how do animals survive?
avoid predators.
find food and space to live.
ability to hunt.
finding mates, reproducing, and raising young.
what triggers the fight-or-flight response?
a stressful/dangerous situation
