exploration can lead to finding many predators. Not exploring at all is also bad, leading to less
food. thusmedium exploration is beneficial.
•Disruptive selection occurs when both extremes of the trait are adaptive and beneficial to
species survival. Ex) if Darwins finches had small flowers and deep flowers; two types of beaks
would be most adaptive.
Please explain whether scientists think evolution has a purpose.
Scientists think evolution has no purpose. It seems that organisms become better and better with time
and the purpose of evolution is the betterment of the species. But evolution doesn’t “know” the
direction of these changes. It doesn’t have a goal in mind. So it doesn’t work towards a predetermined
direction the species must move. The best ex for this is the evolution of the wing (Stephen Jay Gould)
Explain how Prof Gould thinks the wing has evolved. Please try to recall and draw the figure
explaining different selection forces shaping the evolution of the wing
A random mutation caused the existence of small wing. It conferred a selective advantage
that helped thermoregulation. (It flapped -> cooled down; in blood flow) as result, more individuals
with this mutation survived as opposed to many of those who lacked this mutation.
The thermoregulation ability and those who has mutation successfully passed on their genes to
their offspring. Subsequent mutations causing an increase in wingspan increased thermoregulatory
benefits. With a fully developed thermoregulatory organ, a new selective pressure arose
when the wingspan was past that “plateau mask” to serve another purpose other than
what was originally demonstrated. S.J. Gould theorized the above regarding its function
in thermoregulation and when there was no more possible increase in those benefits,
aerodynamic benefits were seen due to a new selective pressure that allowed for its evolution.
Unlike simple reflexes, complex aspects of brain function, including intelligence and consciousness,
cannot be explained by the activity of neurons. FALSE!!!
PLEASE EXPLAIN WHAT THE ACTION POTENTIAL IS AND HOW IT’S GENERATED?
The AP is the change in the cells voltage resulting in an electrical signal that’s passed down through
the neurons; at the end of the pathway it elicits a certain response. It can be inhibitory or exhibitory.
An AP can be generated in numerous ways. The integration of EPSP and IPSP would generate a
potential. It all depends on the balance of inhibitory and exhibitory signals coming into the target
neuron. The potential can result from temporal summation (signal coming fast one after another) or
spatial summation (signal coming from numerous neurons to the target neuron.
In myelinated axons, APs are conducted faster, b/c only the nodes of Ranvier are involved in AP
conduction. Wherever the Schwann cells wrap around the axon, the sodium and potassium ions