Chapters 51 and 52
Paolo DeSordi
Behavioral and Population Ecology
What is behavior?
Proximate Question - focus on environmental stimuli (if any), genetic, physiological, anatomical
mechanisms that trigger behaviors, the “how” questions
Ultimate Question - focus on evolutionary significance of a behavior, the “why” questions
Ethology - the study of how animals behave, particularly in their natural environments. Four basic
questions are the basis of ethology, and they are as follows:
1. What is the mechanical basis of the behavior? (
)
2. How does development of the animal, from zygote to maturity, influence the behavior?
(
)
3. What is the evolutionary history of the behavior? (
)
4. How does the behavior contribute to the fitness of the animal? (
)
Fixed Action Pattern (FAP) - instinctive (unlearned) sequence of behavioral acts carried out until
completion
-Trigged by external sensory stimuli i.e. Sign stimuli
Imprinting - a type of behavior that includes learning as well as innate components and is
generally irreversible
-Distinguishable from other types of learning by the sensitive period - a time in an animal’s
development in which only certain behaviors can be learned
Innate Behavior - ingrained tendency of an organism toward a particular behavior, these
behaviors are generally developmentally fixed and under strong genetic influence
Directed Movements - movements of organisms controlled by genes
• Kinesis - simply the change in activity in response to stimulus
• Taxis - more or less automatic oriented movement toward (positive taxis) or away from
(negative taxis) some stimulus
• Migration - usually long distance movement of organisms, largely under genetic control
Signals - a behavior that causes a change in another animal’s behavior
Communication - essential elements of interactions between individuals
• Chemical Communication - animals emit odors known as pheromones, both
production and responses to pheromones are controlled genetically
• Auditory Communication - use of sounds as a basis of interaction between individuals
Genetic Influences of Mating and Parental Behavior - phenomena such as monogamy is
governed by genes, and the releases of amino acids, hormones
and other chemicals within the
bodies of organisms
Environmental Interactions influence Behavior - while behaviors are controlled by genetic
influences, these behaviors can be modified by environmental influences as well, such as diet and
social interactions
Learning - the modification of behavior based on specific experiences
• Habituation - loss of responsiveness to a stimuli that convey little or no information
• Spatial Learning - modification of behavior based on experience with the spatial
structure of the environment
• Cognitive Map - an internal representation or code of the spatial relationships between
objects in an organism’s surroundings
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Paolo DeSordi
• Associative Learning - ability to associate one feature of the organism’s environment
with another feature.
• Classical Conditioning - arbitrary stimulus in associated with a reward or
punishment
• Operant Conditioning - organism learns to associate one of its own behaviors with
a reward or punishment
• Cognition - ability of an organism's nervous system to perceive store, process, and use
information collected from sensory receptors, the study of animal cognition is called
cognitive ethnology
Behavioral Traits can evolve by Natural Selection - because genes influence behavior, natural
selection can result in the evolution of behavioral traits.
Natural Selection Favors Behaviors that increases Survival and Fitness
Foraging - behaviors that enhance the efficiency of feeding are favored
• Optimal Foraging Theory - compromise between the benefit to nutrition and cost of
obtaining the food
Mating Behavior and Mate Choice - sexual selection favors behaviors that increase the chance
of mating.
• Mating Behavior includes: Promiscuity - no long lasting relationships, Monogamy - one
male and female partner, Polygamy - one male many females (polygyny), or one
female and many males (polyandry)
• Mate choice - central to male behavior and anatomy through intersexual selection
• Agnostic Behavior - ritualized contest determining which competitor gains
resources or mate
• Game Theory - evaluates different strategies used by individuals in a situation
where multiple strategies are used
Inclusive Fitness and Altruistic (Selfless) Behavior - many behaviors only aid one individual
(selfish) and may indirectly harm others, but inclusive fitness (effect an individual has on
proliferating its gene by raising its own young and aiding in raising the young of close relatives)
leads to altruistic behavior.
• Hamilton’s Rule r(coefficient of relatedness)B(benefit) > C ( cost of altruism)
• Reciprocal Altruism - altruism towards unrelated individual leading to more altruism in
the future (returning the favor)
Social Learning - learning by observing others
• Culture - information transferred through social learning and teaching that influences
the behavior of individuals in a population
• Mate Choice Copying - individuals in a population copy the mate choice of others
• Sociobiology - study of the biological aspects of social behavior
Population Ecology - study of populations in relation to their environment
Exponential Model - ∆N/ ∆t (Change in population over time) = B (births) - D (deaths). The per
capita rate of increase ( r ) is equal to r = b (per capita births) - m (per capita deaths). If the
population is growing (r>0), decreasing (r<0) or if there is zero population growth (r=0). Using per
capita rate of increase the formula is now ∆N/ ∆t = rN. Using calculus the instantaneous growth
rate can be found using the formula dN/ dt = rN
Chapters 51 and 52
Paolo DeSordi
Exponential Growth - population growth under ideal circumstances, the per capita rate of
increase may assume the maximum rate for the species called the intrinsic rate of increase ( rmax ).
The equation is dN/ dt = rmaxN
Populations are Regulated by Abiotic and Biotic Influences
Density Independent - characteristics that are not affected by population density
Density Dependent - characteristics that vary according to change in population density
• Competition for Resources - less available nutrient for animals, lowers birth rate
• Territoriality - animals require certain amount of space for dens, nests etc
• Health - higher density, higher probability of transmittance of diseases
• Predation - predators favor prey that is in higher supply (high population density)
• Toxic Wastes - as density increases higher waste accumulates
• Intrinsic Factors - physiological factors can regulate population density
Population Dynamics - Interactions between biotic and abiotic factors influence variation in
population size. Some populations can remain relatively stable while others fluctuate over time.
While many populations fluctuate at unpredictable intervals, others undergo regular fluctuations,
known as population cycles
Metapopulation - Linked populations with individuals that immigrate and emigrate between them.
QUIZ
1. A male stickleback fish will attack other male stickleback fish that invade its territory. A
proximate cause to this behavior is:
Chapters 51 and 52
Paolo DeSordi
A - Male stickleback fish do not cooperate
B - Male stickleback fish are competing for mating rights within the population
C - Male stickleback fish will attack any intruder
D - The invading male stickleback acts as a sign stimulus and the other male becomes aggressive
2. All of the following are an example of kinesis accept for
A - Trout will face the current when looking for prey
B - Sow bugs will look for shade when exposed to the sun
C - When a human touches a hot kettle they will recoil their hand
D - A male moth will fly towards an area of greater pheromone concentration looking for a mate
3. Examples of mating behaviors include:
A - Monogamy
B - Promiscuity
C - Habituation
D - All of the above
E - A and B
4. The male Greater Bird-of-paradise is known for its dazzling feathers and courtship display, the
complex courtship display may put the male at risk of predation, this is an example of:
A - Egotistical Behavior
B - Altruistic Behavior
C - Agnostic Behavior
D - Paternal Behavior
5. An eagle is searching for a mouse in a field to eat; there is an extremely small (1 g) mouse 10 m
away, a large mouse (5 g) 15 m away, and a slightly larger mouse (6 g) 100 m away. According to
the Optimal Foraging Theory, which mouse will the eagle most likely try to catch?
A - 1 g mouse
B - 5 g mouse
C - 6 g mouse
6. A naked mole rat mother will care for its own young as well as the young of its closet’s relative;
this behavior is an example of:
A - Intersexual Selection
B - Social Learning
C - Altruism
D - Mate Choice Copying
7. After many repetitions a household dog will learn to sit when its owner says the command “sit”.
While training the dog to do this task the owner will use a reward such as a dog biscuit. This
behavior is an example of:
A - Taxis
B - Classical Conditioning
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Paolo DeSordi
C - Fixed Action Pattern
D - Spatial Learning
8. In a sample population of monarch butterflies 21 out of the 1000 butterflies died and there were
32 births in that same population of 1000 in one year. There is a population of 300 monarch
butterflies living in a single park, based on the information gathered from the sample population
what is the per capita rate of increase in one year of the population living in the park? (To one
decimal place)
A - 9.6
B - 11.0
C - 15.9
D - 3.3
9. Which of these options contains only factors that are density-dependent regulators of a
population?
A - Promiscuity, Health, Competition for Resources, Cooperation
B - Health, Social Learning, Toxic Wastes, Predation
C - Territoriality, Competition for Resources, Predation, Intrinsic Factors
D - Predation, Population Cycles, Stability, Toxic Wastes
10. Different males of the same species of bird exhibit different coloured feathers, all are equally
successful at finding a mate, this is an example of:
A - Kin selection
B - Conceded female birds
C - Mimicry
D - Game Theory
Short Answer:
Canadian Geese living on the eastern coast of Canada prefer eating slugs and other small insects,
while geese living in central Canada prefer grass and grains. Provide a possible reasoning that the
same species of geese prefer eating different things. Create a possible experiment to solidify you
argument.
Answers
1. D
2. A
Short Answer
3.E
4.C
5.B
6.C
7.B
8.D
9.C
10.D
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Paolo DeSordi
The same species of geese preferring different foods is an example of behavioral variation in
natural populations, meaning that these different population’s behaviors have evolved to best
ensure survival. A possible test is to introduce the eastern geese to the central region where their
normal source of food is present but less abundant, if the geese eat the same food they preferred
on the east coast, it can be concluded that the behaviors have changed. Similarly central geese
can be placed in the eastern coast habitat and their food choices can also be monitored, and the
same results will most likely be observed, with the geese preferring their habitual food source as
oppose to the more readily available one.