Important words and concepts
from Chapter 51, Campbell & Reece, 2002
(3/25/2005):
by Stephen T. Abedon (abedon.1@osu.edu)
for Biology 113 at the Ohio State University
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Course-external links are
in brackets Click [index] to access site index Click here to access
text’s website Vocabulary
words
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(1) Chapter title: Behavioral Biology
(a)
[glossary of terms used in animal behavior and evolution
(Behavioral Ecology – Jane Brockmann – University of Florida)]
(b)
[behavioral biology
(Google Search)]
[index]
(a)
We expect natural selection
to attempt to maximize the Darwinian fitness
associated with the traits possessed by organisms
(b)
The goal of a behavioral ecologist is to explain behaviors in terms of
their impact on Darwinian fitness
(c)
As with any trait (given an “adaptationist paradigm”), the behavior
of an organism, too, we expect to be Darwinian-fitness enhancing
(d)
That is, behaviors that reduce Darwinian fitness we predict will be
lost from gene pools while behaviors that increase
Darwinian fitness we expect to increase in frequency within populations
(e)
Note, however, that while behaviors often have underlying genetic
components, the ability of organisms to learn complicates our understanding of
behavioral evolution; nevertheless, we have an expectation that organisms will
have a tendency to behave in a manner that enhances their Darwinian fitness
(f)
[behavioral ecology
(Google Search)]
[nebraska behavioral biology group] [animal behaviour--zoological
record (Biosis)] [index]
(a)
What is behavior?
(i)
Defined extremely broadly, behavior is how organisms act in response to
environmental stimuli, with the word "act" (as well as the phrase
"environmental stimuli") left somewhat ambiguous
(ii)
Clearly organisms act or react physiologically to all sorts of
environmental stimuli (e.g., Escherichia
coli's modification of gene expression in response to low levels of the sugar glucose and high levels of sugar lactose)
(b)
The study of behavior becomes interesting when behaviors
(i)
are not obviously in the organism's best interest
(ii)
when the cost of the behavior is high even given that ultimately the
behavior serves the organism's Darwinian interests (e.g., in terms of energy
required to learn or display the behavior, or when the maintenance of costly
anatomical features, e.g., a large brain, is necessary for the display of the
behavior), or
(iii)
when the behavior appears to be overly simplistic but still sufficient
to get the job done (e.g., FAPs)
(c)
We would say that an organism's behavior is optimized when the
organism's Darwinian fitness is optimized given the display of that behavior
relative to the display of some alternative behavior, including the display of
no behavior at all (“If you choose not to decide,
you still have made a choice.”)
(d)
Behavior typically influences the acquisition of energy, nutrients,
sex, help in child rearing, removal of ectoparasites,
survival, establishment and maintenance of dominance hierarchies, etc.
(e)
Note that whereas behavior is traditionally studied with animals,
unless defined in some way that excludes all other kingdoms (e.g., requiring
muscles or a nervous system) then behavior is the province of members of all
kingdoms (plus their viruses); nevertheless, behavior obviously is displayed
with a greater complexity by animals so the animal-emphasis of behavioral
ecology is quite justified
(f)
[behavior (Google Search)]
[index]
(a)
When we question why a behavior occurs (or, for that matter, why any
trait exists), we are posing a question of ultimate causation
(b)
Ultimate causation is simply another way of saying optimization of Darwinian fitness
(c)
The ultimate cause of a behavior is its increase in frequency within a
population due to the greater Darwinian fitness that results from organisms
engaging in that behavior
(d)
Thus, when questioning ultimate causation, one is simply asking why a
behavior evolved
(e)
The hallmark of the discipline called behavioral ecology
is its emphasis on determining the ultimate causation of behaviors
(i)
Understanding the ultimate causation of some behaviors can be very
straightforward (a female songbird mates to have babies)
(ii)
Interesting questions in
behavioral ecology are those that are less straightforward (e.g., a female songbird
mates with someone other than her lifetime mate or why a bird would push her
own eggs out of her own nest)
(f)
[ultimate causation
(Google Search)]
[index]
(a)
In contrast with ultimate causation, proximate causation
involves the mechanics of how a behavior occurs including
(i)
how stimuli are received
(ii)
how received stimuli are translated into a response, and
(iii)
the mechanisms underlying the response (i.e., the behavior)
(b)
A behavioral ecologist assumes that the proximate cause of a behavior
is simply the mechanism underlying the means by which a behavior is
manifest
(c)
"Thus, the 'how' and 'why' questions about animal behavior are
related in their evolutionary basis: Proximate mechanisms produce behaviors
that ultimately evolved because they increase fitness in some way."
(d)
As such, a behavioral ecologist is interested in proximate causation
only to the extent that these mechanisms serve to constrain the evolution of
specific behaviors
(e)
It should not be overlooked that understanding how behaviors are
constrained by an organism's anatomy and physiology is highly relevant;
however, otherwise becoming mired down in the details of the anatomy and
physiology of a behavior can be somewhat distracting to one's understanding of
the ecology of a behavior, so proximate causation is frequently accepted as a
given (i.e., the behavior happens so the organism must be anatomically,
physiologically, and mentally capable of expressing the behavior)
(f)
[proximate causation
(Google Search)]
[links related to animal
perception (Animal Learning &
Cognition)] [index]
(6) Umvelt (supplemental discussion)
(a)
This is the term used to describe the means by which proximate causation underlies the display of a given behavior,
that is, the anatomical, physiological, and environmental (?) context
underlying and allowing a behavior to occur
(b)
[umvelt (Google Search)]
[how animals see (Animal Learning &
Cognition)] [index]
(a)
Behavioral ecology as a discipline had its roots in the more proximate causation-concerned field of ethology
(b)
Ethology, however, is less concerned about learning and more concerned
about innate, not-learned behaviors
(c)
"One of the major findings of ethology was that animals can carry
out many behaviors without ever having seen them performed. In other words,
many behaviors are innately programmed. And while such behaviors seem
purposeful because they are clearly beneficial, they are carried out in ways
that show the animals are unaware of the significance of their actions."
(d)
These are examples of innate behaviors:
(e)
[ethology (Google Search)]
[ethology and evolution on the web (The International Society for Human Ethology)]
[index]
(8) Fixed action
patterns (FAP) [sign
stimulus, releaser]
(a)
A fixed-action pattern is a series of behaviors that are both innate
and, typically, are completed in full once initiated (even if their completion
is laughably inappropriate)
(b)
The initiation of a fixed action pattern is in response to an external
sensory stimulus known as a sign stimulus
or a(n innate) releaser
(c)
The reason why FAPs are not always appropriate is because the releaser
for the action is often a proximate correlate
to the stimulus ("a limited subset of the available sensory
information") that while the FAP is ultimately (i.e.,
evolutionarily) a response to some full stimulus
(d)
"We can think of a FAP as the innate ability of an animal to
detect a certain stimulus associated with the animal's umvelt, combined
with an innate behavioral program that is activated by the stimulus to direct
some kind of motor activity."
(e)
"In the case of a FAP, the animals are behaving more like
robots."
(i)
However, the important thing to keep in mind is that the FAP under natural
conditions typically represents the energetically minimal investment in the
display of a behavior that otherwise is good enough (i.e., evolution is not
just optimizing the outcome of the behavior but also optimizing the efficiency
of the behavior such that behavioral outcome for energy invested is maximized)
(ii)
"The ability to confront novel stimuli, learn about them, and
adjust behavior is a hallmark of both intelligence and self-awareness. The
evolution of intelligence is costly, in both the development of the neural
tissue necessary to process the information and its metabolic maintenance. In
addition, the evolution of intelligence requires dramatic changes in life
history patterns, such as long juvenile phases and high parental investment per
offspring. For most species, these costs, measured as reductions in
reproductive fitness, far outweigh the costs of an occasional inappropriate use
of FAPs, and extensive intelligence has not evolved in many animal
groups."
(iii)
"Some ethologists have suggested that the use of
simple cues to release programmed behavior prevents an animal from wasting time
processing or integrating a wide variety of input. Perhaps a better way of
interpreting the situation has to do with the limitations of innate behavior
and how it evolved. A frog's sensory-neural network for detecting movement is
probably much less complex than the apparatus that would be necessary to
rapidly distinguish a fly from another object of similar size. In any case,
simple cues usually work quite well in an animal's normal sensory world, though
not in the experimental world ethologists often create."
(f)
[egg rolling animated gif
(1.8 MB file), chick hatching movie
(600 KB) (Behavioral Control Systems)]
[fixed action patterns,
sign stimulus, innate releaser (Google Search)]
[stimuli and innate behavior
(Bio 170 – Animal Behavior
– Barry Sinervo)] [index]
(a)
Learning is synonymous with behavioral modification such that, ideally,
a behavior is further optimized by the change
(b)
Learning can optimize behavior most obviously in a short term sense;
however, for behavior to be truly optimized, it must be optimized in a
Darwinian sense
(c)
"Nearly all biologists today agree that most behavior is a
consequence of genetic and environmental influences. Even though an animal may
not have to witness a FAP because the basic behavior is innate, learning is
still involved. Most FAPs improve with performance, as animals learn to carry
them out more efficiently."
(d)
Learning may be differentiated into a number of different types and
associated concepts:
(i)
Maturation (not learning at all)
(ii)
Habituation (learned ignoring)
(iii)
Imprinting (learned sign stimulus)
(iv)
Associative learning
·
Classical conditioning (Pavlov's dog)
·
Operant conditioning (trial and error learning)
(v)
Observational learning (copying)
(vi)
Play
(practicing)
(vii)
Insight learning (assessment of novel
situations)
(e)
[animal learning (Google Search)]
[index]
(a)
Learning must be operationally distinguished from maturation
(b)
That is, just because an animal improves its performance of a behavior
with time does not mean that the animal is improving through learning; it could
instead mean that the animal was physiologically or anatomically unable to
properly or fully display the behavior until they have reached an appropriate
developmental stage
(c)
Such development-associated improvements in behaviors occur via
maturation
(d)
[animal maturation and learning
(Google Search)]
[index]
(a)
Habituation is one means by which animals adapt behaviorally to their
environment (i.e., learn)
(b)
Habituation is the learned ignoring of a stimulus
(c)
This occurs when an animal learns that a stimulus is not appropriately
correlated with the expected full stimulus
(d)
Thus, habituation is a means of, for example, energy conservation
employed when proximal stimuli are not followed by
subsequently expected stimuli
(f)
[animal habituation and
learning (Google Search)]
[index]
(12) Imprinting (critical period)
(a)
(b)
Two things distinguish imprinting from other types of learning
(i)
An imprint, once learned, is never forgotten (i.e., imprinting is
irreversible)
(ii)
An imprint can only be learned during a critical period, which is defined (somewhat tautologically) as the
limited time during which an imprint may be learned
(c)
"While a critical period and irreversibility characterize
imprinting, it now recognized that these phenomena are not always rigidly
fixed." That is, it is possible, though not easy, in some
situations/species for an animal to eventually modify its behavior to disregard
imprinting
(d)
See Figure 51.9, Imprinting
(e)
[imprinting, definition]
[imprinting, imprinting "critical
period" (Google Search)] [index]
(a)
Associative learning is the association of one stimulus with another
(b)
See classical conditioning and operant conditioning as examples
(c)
[associative learning
(Google Search)]
[index]
(a)
Classical conditioning is the occurrence of associative learning following repeated, correlated exposure
to two stimuli
(b)
In classical conditioning each stimulus becomes equivalent in terms of
the behavioral response
(c)
Thus, otherwise irrelevant correlates to relevant stimuli can come to
induce identical responses (e.g., the ringing of bells with the smell/taste of
food; the opening of refrigerators or the rustling of plastic bags and the
whistling response by guinea pigs used to being fed “fresh” produce)
(d)
[classical conditioning
(Google Search)]
[index]
(a)
Operant conditioning is trial-and-error learning
(b)
Operant conditioning works (in an ultimate, Darwinian
sense) so long as an animal possesses a reasonable means of distinguishing good
from bad
(i)
Using these terms in their ultimate, Darwinian sense, e.g., a good
thing results in more offspring while a bad thing results in less offspring
(c)
This means of distinguishing good from bad requires either a reasonable
idea of the future consequences of one's actions (e.g., as humans supposedly
possess) or some kind of physiological indicator of good and bad, which in
animals is represented (probably) as pleasure and pain
(d)
Thus, animals continue to do things that give them pleasure while
refraining from doing things that cause them pain
(e)
Keep in mind that the reaction of pleasure or pain is itself a product
of natural selection, such that things that tend
to enhance Darwinian fitness tend to be pleasure-filled while those things that
tend to diminish Darwinian fitness are painful
(i)
Of course, if an environment changes then the correlation between
painful and diminishment of Darwinian fitness or pleasurable and enhancing of
Darwinian fitness may be lost
(f)
Note that while classical conditioning
is the association of two stimuli such that an animal anticipates a result (one
the stimuli; e.g., food) given the stimulation by the other (e.g., a bell), in
operant conditioning the second stimulus in a sense is internal rather
than external: the animal associates stimuli either with pleasure or with pain
and learns to seek out those stimuli that elicit the former and avoid those
that elicit the latter; thus, classical conditioning involves the association
of two external stimuli while operant conditioning involves a learned
association between an external stimulus and an internal state
(g)
See Figure 51.11, Operant
conditioning
(h)
[operant conditioning
(Google Search)]
[index]
(a)
Observational learning is the copying of the actions of others
(b)
The assumption is that others, by having survived, etc., possess
behaviors that are worth knowing
(c)
Note that by this logic the worth of another's behavior (i.e.,
whether that behavior is worth copying) diminishes with the age of the other
such that while the behavior of an older individual may be worth copying
(i)
The behavior of a same-aged individual is less worthwhile
(ii)
The behavior of a younger individual has the least worth of all
(d)
[observational learning
(Google Search)]
[index]
(a)
Play is essentially practice
(b)
The more we practice, the better we get at something (which ideally
enhances our survival or reproductive success); this "getting better"
can be in terms of the acquisition of skill or in the development and
maintenance of musculature that will be relevant to possess once even extended
parental care is no longer available
(c)
Consequently, the finding of pleasure in play is our body's way of
making sure that we practice
(d)