Transcript Ch 51-54 Review Lecture

Chapter 51-54 Review Lecture
1. Differentiate between ultimate
and proximate causation for an
animal behavior. Use an example.
These questions highlight the complementary nature of
proximate and ultimate perspectives
• Proximate causation, or “how” explanations,
focus on
– Environmental stimuli that trigger a behavior
– Genetic, physiological, and anatomical
mechanisms underlying a behavior
• Ultimate causation, or “why” explanations,
focus on
– Evolutionary significance of a behavior
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
2. Define and give an example of
a fixed action pattern.
Fixed Action Patterns
• A fixed action pattern is a sequence of
unlearned, innate behaviors that is
unchangeable
• Once initiated, it is usually carried to
completion
• A fixed action pattern is triggered by an
external cue known as a sign stimulus
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
3. Define and give an example of
habituation.
Concept 51.2: Learning establishes specific links
between experience and behavior
• Innate behavior is developmentally fixed and
under strong genetic influence
• Learning is the modification of behavior based
on specific experiences
1. Habituation is a simple form of learning
that involves loss of responsiveness to
stimuli that convey little or no information
– For example, birds will stop responding to alarm
calls from their species if these are not followed
by an actual attack (“cry-wolf”)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
4. Define and give an example of
imprinting.
2. Imprinting
• Imprinting is a behavior that includes learning
and innate components and is generally
irreversible
• It is distinguished from other learning by a
sensitive period: limited developmental phase
that is the only time when certain behaviors
can be learned
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
5. Define and give an example of
spatial learning..
3. Spatial Learning
• Spatial learning is a more complex
modification of behavior based on experience
with the spatial structure of the environment
• Niko Tinbergen showed how digger wasps use
landmarks to find nest entrances
• A cognitive map is an internal representation
of spatial relationships between objects in an
animal’s surroundings
– For example, Clark’s nutcrackers can find food hidden in caches
located halfway between particular landmarks
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Associative Learning
• In associative learning, animals associate
one feature of their environment with another
– For example, a white-footed mouse will avoid
eating caterpillars with specific colors after a bad
experience with a distasteful monarch butterfly
caterpillar
– There are two types
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
6. Differentiate between operant
and classical conditioning. Use
examples.
• Classical conditioning is a type of associative
learning in which an arbitrary stimulus is
associated with a reward or punishment
– For example, a dog that repeatedly hears a bell
before being fed will salivate in anticipation at the
bell’s sound
• Operant conditioning is a type of associative
learning in which an animal learns to associate one
of its behaviors with a reward or punishment
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
7. Explain how an animal uses
the optimal foraging model.
Optimal Foraging Model
• Optimal foraging model views foraging
behavior as a compromise between benefits
of nutrition and costs of obtaining food
– The costs of obtaining food include energy
expenditure and the risk of being eaten while
foraging
• Risk of predation affects foraging behavior
– For example, mule deer are more likely to feed in
open forested areas where they are less likely to
be killed by mountain lions
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
8. Differentiate between intersexual
and intrasexual selection. Give
examples of each.
Sexual Selection and Mate Choice
• In intersexual selection, members of one sex
choose mates on the basis of certain traits
• Intrasexual selection involves competition
between members of the same sex for mates
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
9. Define inclusive fitness and
explain how kin selection, using
Hamilton’s Rule, shows it.
Inclusive Fitness
• Altruism can be explained by inclusive fitness
• Inclusive fitness is the total effect an
individual has on proliferating its genes by
producing offspring and helping close relatives
produce offspring
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Hamilton’s Rule and Kin Selection
• William Hamilton proposed a quantitative
measure for predicting when natural selection
would favor altruistic acts among related
individuals
• Three key variables in an altruistic act:
– Benefit to the recipient (B)
– Cost to the altruist (C)
– Coefficient of relatedness (the fraction of genes
that, on average, are shared; r)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Hamilton’s Rule and Kin Selection
• Natural selection favors
altruism when:
rB > C
• This inequality is called
Hamilton’s rule
• Kin selection is the natural
selection that favors this kind
of altruistic behavior by
enhancing reproductive
success of relatives
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
10. Describe the life history
strategies of Type I, Type II, and Type
III survivorship curves.
• Survivorship curves can be classified into three
general types:
– Type I: low death rates during early and middle
life, then an increase among older age groups
(humans)
– Type II: the death rate is constant over the
organism’s life span (squirrels)
– Type III: high death rates for the young, then a
slower death rate for survivors (oysters)
Number of survivors (log scale)
Fig. 53-6
1,000
I
100
II
10
III
1
0
50
Percentage of maximum life span
100
Evolution and Life History Diversity
• Life histories are very diverse
• Species that exhibit semelparity, or big-bang
reproduction, reproduce once and die
• Species that exhibit iteroparity, or repeated
reproduction, produce offspring repeatedly
• Highly variable or unpredictable environments
likely favor big-bang reproduction, while
dependable environments may favor repeated
reproduction
11. Explain exponential population
growth and how it differs from
logistic population growth. Relate it
to carrying capacity using a specific
example.
Exponential Growth
• Exponential population growth is population
increase under idealized conditions
• Under these conditions, the rate of
reproduction is at its maximum, called the
intrinsic rate of increase
• Equation of exponential population growth:
dN 
rmaxN
dt
• Exponential
population growth
results in a Jshaped curve
• The J-shaped
curve of
exponential
growth
characterizes
some rebounding
populations
Concept 53.4: The logistic model describes how a population grows
more slowly as it nears its carrying capacity
• Exponential growth cannot be sustained for
long in any population
• A more realistic population model limits growth
by incorporating carrying capacity
• Carrying capacity (K) is the maximum
population size the environment can support
The Logistic Growth Model
• In the logistic population growth model, the
per capita rate of increase declines as carrying
capacity is reached
• We construct the logistic model by starting with
the exponential model and adding an
expression that reduces per capita rate of
increase as N approaches K
(K  N)
dN
 rmax N
dt
K
• The logistic model of population growth
produces a sigmoid (S-shaped) curve
12. Differentiate between r-selected
and k-selected life history strategies.
The Logistic Model and Life Histories
• Life history traits favored by natural selection
may vary with population density and
environmental conditions
• K-selection, or density-dependent selection,
selects for life history traits that are sensitive to
population density
• r-selection, or density-independent selection,
selects for life history traits that maximize
reproduction
13. Give two examples for both
density-dependent and densityindependent growth factors.
Population Change and Population Density
• In density-independent
populations, birth rate and
death rate do not change
with population density
• In density-dependent
populations, birth rates fall
and death rates rise with
population density
(negative feedback)
14. Compare and contrast
Batesian and Mullerian mimicry.
• Animals with effective chemical defense often exhibit
bright warning coloration, called aposematic coloration
• Predators are particularly cautious in dealing with prey
that display such coloration
• In some cases, a prey species may gain significant
protection by mimicking the appearance of another
species
• In Batesian mimicry, a palatable or harmless species
mimics an unpalatable or harmful model
• In Müllerian mimicry, two or more unpalatable species
resemble each other
Fig. 54-5
(a) Cryptic
coloration
Canyon tree frog
(b) Aposematic
coloration
Poison dart frog
(c) Batesian mimicry: A harmless species mimics a harmful one.
Hawkmoth
larva
Green parrot snake
(d) Müllerian mimicry: Two unpalatable species
mimic each other.
Cuckoo bee
Yellow jacket
Fig. 54-12
Humans
Smaller
toothed
whales
Baleen
whales
Crab-eater
seals
Birds
Leopard
seals
Fishes
Sperm
whales
Elephant
seals
Squids
Carnivorous
plankton
Euphausids
(krill)
Copepods
Phytoplankton
15. Using the food web below
determine which are dominant
species and keystone species.
Dominant Species/Keystone Species
• Dominant species are those that are most
abundant or have the highest biomass
– Dominant species exert powerful control over the
occurrence and distribution of other species
– Invasive species, typically introduced to a new
environment by humans, often lack predators or disease
• Keystone species exert strong control on a
community by their ecological roles, or niches
– In contrast to dominant species, they are not
necessarily abundant in a community
16. Differentiate between primary
and secondary ecological
succession.
Ecological Succession
• Ecological succession is the sequence of
community and ecosystem changes after a
disturbance
• Primary succession occurs where no soil
exists when succession begins
• Secondary succession begins in an area
where soil remains after a disturbance
• Early-arriving species and later-arriving
species may be linked in one of three
processes:
– Early arrivals may facilitate appearance of later
species by making the environment favorable
– They may inhibit establishment of later species
– They may tolerate later species but have no
impact on their establishment