DEFINE BRIEFLY WHAT THE “PHENOGENETIC QUESTIONS” AND “PHYLOGENETIC
QUESTIONS” OF ANIMAL BEHAVIOUR ARE.
Proximate QUESTION (phenogenetic causation) concerns the biological and physiological
mechanisms of behaviour; “How do things work?”
Ultimate QUESTION (phylogenetic causation) concerns the evolution and adaptive aspect of
behaviour; “How did it come about?”
EXPLAIN WHY THE ANALYSIS OF ANIMAL BEHAVIOUR MAY HAVE ADVANTAGES OVER
STUDYING HUMAN BEHAVIOUR.
•Investigation of behaviour of multiple animal species is possible and this comparative approach
can be powerful for the understanding of both the evolution and the mechanisms of behaviour.
•Animals can be studied in the laboratory under rigorous control using methods unavailable
or inappropriate for human subjects.
•Animal behaviour can be simpler than human behaviour and thus can be used to model
some basic features of human behaviour.
•Animal studies can be used to model human diseases and thus help us develop treatment.
Animal psychology stresses controlled laboratory conditions and focuses on general phenomena
while ethology in more nature aware and focuses on species specific characteristics. TRUE
•Species appear to change with time TRUE
•Change often reflects adaptations to natural surroundings TRUE
•There is an overproduction of offspring and not all of the offspring survive.
Only the best, “the fittest” will make it. TRUE
•, there must be selection for certain characteristics and against certain other ones. TRUE
PLEASE GIVE THE DEFINITION OF FITNESS/ EVOLUTIONARY FITNESS
Fitness is the number of viable offspring that reach reproductive age.
Fitness is about how many genes an individual can successfully pass onto the next generation.
Explain the three types of selection forces we discussed
•Directional selection occurs when a certain extreme trait becomes much more adaptive and
beneficial to species survival. Ex) Darwins finches, if a niche was discovered /where only deep
flowers were located,/ the beaks of finches would switch direction towards a longer, thinner beak.
•Stabilizing selection occurs when neither extreme of the trait is beneficial but the middle
variation of the trait is. Ex) it’s beneficial for rats to explore (find food and mates) but too much
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
cannot cross the membrane; the Schwann cells wrap too tightly around the axonal membrane for
there to be any extracellular space underneath them. , the only place that an AP can occur is at the
node of Ranvier- the space between the Schwann cells. B/c of this, the AP jumps from node to node
along the axon.
Please explain what the resting potential is, and how it’s maintained.
The resting potential is found within a neuron /when all chemical and electric forces are balanced at
-65mV /within the cell. Since some of the Na+ and K+ channels allow movement of these molecules
which would disrupt the potential an active transport pump is present. Using E from the release of the
Phosphate from ATP the pump brings out 3 Na+ for every 2K+ it brings into the cell. This maintains
the -65mV within the cell.
PLEASE EXPLAIN WHAT HAPPENS WHEN AN AP ARRIVES AT THE PRESYNAPTIC
TERMINAL, I.E. HOW IS THIS SIGNAL TRANSMITTED TO THE POSTSYNAPTIC NEURONE?
•When a single AP arrives at the presynaptic terminal, it causes Ca+ channels to open, increasing
ion permeability of presynaptic terminal cell membrane.
•Ca2+ enter the presynaptic terminal and cause vesicles to release their neurotransmitter,
acetylcholine (Ach) into the presynaptic cleft.
•Diffusion of Ach across the synaptic cleft and binding of Ach to Ach receptors on postsynaptic
membrane causes an increase in the permeability of sodium ion channels. The movement of Na+
into the cell results in depolarization of the postsynaptic membrane. Once threshold has been
reached, a postsynaptic AP is generated and is propagated over the cell membrane.
PLEASE BRIEFLY DESCRIBE THE STRUCTURE and FUNCTION OF DNA.
•DNA is a double helix that’s packaged tightly into chromosomes by histone proteins. It’s
comprised of 4 different nucleotide bases. Adenine, Thymine, Guanine and Cytosine.
The base pairs are attached to a sugar phosphate backbone /to form one of two strands of a DNA
molecule. The direction of each strand in a DNA molecule is defined as 5' for the beginning, and 3'
for the end. The 5' and 3' terms refer to the position of the bases relative to the sugar molecule in
the DNA backbone.
•DNA's function is to provide the code on which all life is based. DNA also functions to pass
along all of these important instructions to the next generation.
Please explain why behavioural characteristics often do not follow a simple Mendelian
Define briefly what the phenogenetic questions and phylogenetic. Proximate question (phenogenetic causation) concerns the biological and physiological mechanisms of behaviour; how do things work? . Ultimate question (phylogenetic causation) concerns the evolution and adaptive aspect of behaviour; how did it come about? . Explain why the analysis of animal behaviour may have advantages over. Animal psychology stresses controlled laboratory conditions and focuses on general phenomena while ethology in more nature aware and focuses on species specific characteristics. True: species appear to change with time true, change often reflects adaptations to natural surroundings true, there is an overproduction of offspring and not all of the offspring survive. Only the best, the fittest will make it. True: , there must be selection for certain characteristics and against certain other ones. Please give the definition of fitness/ evolutionary fitness. Fitness is the number of viable offspring that reach reproductive age.