Download Biology Option Review Section E

Biology Option Review
Section E
E.1.1.
• Stimulus: A stimulus is an event, sensation, or
movement of some kind that triggers a response within
the body either chemically or can also manifest itself as
an external physical response.
• Response: A response is the body’s reaction to an outer
environmental stimulus, such as a drop in temperature or
a potential threat, which can either be an innate reflex or
a conscious decision.
• Reflex: A reflex is an innate reaction that the body
performs automatically in response to certain stimuli that
the body encounters, such as the blood arterioles
contracting away from the skin surface to reserve heat
as much as possible in harsh cold temperatures in
humans.
E.1.2.
• Receptors are the first hand portions of the reactions to stimuli as
they are part of the sensory neurons that allow the neurons to detect
a foreign stimulus that the body must react to. The sensory
neurons, after receiving the message that a stimulus has presented
itself, relays the message onto the relay neurons which receive the
message in a variety of forms depending on which sense has
received the stimulus and which sensory neuron has delivered the
message. The relay neurons then straight-shoot the message to the
motors neurons to initiate a response. The motor neurons then
decide whether the response is a reflex or if the choice should be
conscious and trigger the synapses to turn on. The synapses then
sort the correct neurotransmitters sent through and kick-start the
actual response from the body by sending the message to the
effectors. The effectors then, depending on the previous stages,
elicit wither a physical or chemical response from the body to react
to the new stimulus presented to it. All of this happens in mere
microseconds.
E.1.3.
E.1.4.
•
Animal responses can be affected by natural selection in regards to higher
rates of survival, as is the case with the Loggerhead turtles who are, after
birth and successful survival until reproduction can occur, able to
instinctively remember the beach they were born on, known as natal
beaches, and travel immense distances when the time comes to lay their
eggs, back to the beaches where they were born as they were able to
survive themselves, thus the beach has a higher rate of survival. Through
the Loggerhead turtles we see that the high survival rate importance from
natural selection has affected this species by making them able to, from
birth, memorize the exact location where they were born. Another example
of this is the Asian Honeybee which builds its nest in dense foliage to avoid
detection by predators. In a study done on the bees, it was found that if the
foliage around the nest is removed, the nest is easily spotted and destroyed
by predators, but under the heavy leaf coverage provided by the trees and
bushes the nest remains safe and inconspicuous to predators. This
behavior by the bees shows that, through the emphasis of the necessity of
higher survival rates, this species has learned how to cope with predators
finding their nests by camouflaging themselves with the nearby brush and
foliage provided by their environment.