BEHAVIOR

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BEHAVIOR

• Review for Lecture 471

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Figure 47.13a
Crane courtship display
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most important concept

•      
• Behavioral choices in animals are mostly
  genetically-controlled instincts. Sometimes their
  evolution seems to be a paradox, because some
  behaviors apparently decrease an individual's
  fitness.
• So you need to know about
  the DNA tools

4
Does this behavior increase these
individuals fitness?
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Proximate or Ultimate

• How (mechanism) or Why (the fitness angle)
• genetics and physiology how or why? (mostly
  ..
• evolution and ecology how or why? (mostly ..

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MECHANISMS (proximate)

• Neural (response controlled by nerves)
• hormonal (response produced by .)
• pheromonal (response controlled by .
• GENES control timing of the production of
  proteins which build the nerves and the hormone
  receptors and the sense organs etc.

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Behavioral Traits influenced by genes
and environment

• Nature - genotype - instinct - innate -
  congenital (born that way)
• response to light?
• Nurture - learning - environment - culture

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Figure 47.5
Early spring
Late winter
Spring
Neurons in songcenters bind testosterone.Neuron
s divide andincrease activity.Song
centerenlarges.
Signals fromsong centersstimulate musclesat
syrinx.Song results.
Sensory organs record increasing day lengthsand
temperatures.Brain releases signalinghormones.
Testes enlargein responseto hormonal signals
Testes secretetestosterone
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Does this behavior increase this
individual's fitness?
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most important concept

•      
• Behavioral choices in animals are mostly
  genetically-controlled instincts. Sometimes their
  evolution seems to be a paradox, because some
  behaviors apparently decrease an individual's
  fitness.
• So you need to know about
  the DNA tools

11
Behavior CHOICES

• Move to new feeding site or stay here?
• Move to new territory/social group or not?
• Help my pack members or not? Smile or growl?
• Advertise for a mate now or later? Where? What
  to wear? Invest in cologne?
• To breed or not to breed? How often? This mate
  or another one? One mate or more?
• Feed babies or not? How much and what?

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Nature selects behaviors which improve fitness
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Proximate cause of chimps smile instinctive
response to a learned social stimulus?
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Ultimate cause of chimps smile how does it
increase his fitness?
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Figure 47.11
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Does this behavior increase this
individual's fitness?
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Box 47.4 Figure 1b
Calculating coefficient of relatedness
B
C
Sisters share 1/2 of alleles
Mother and daughter share 1/2 of alleles
Mother and son share1/2 of alleles
D
A
A and B (first cousins) share 1/2 x 1/2 x 1/2
1/8 alleles
Coefficient of relatedness (r) 0.125
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Immigration or habitat "choice"

• (how and when should a critter move? What genes
  does it need?)
• most species seem to emigrate and immigrate in
  "logical/optimal" patterns, especially when they
  have genes for the appropriate anatomical
  equipment

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Optimal foraging theory

• critter should have instincts which make it
• maximize its energy benefit (find lots of prey or
  food)
• minimize its risk of dying (like in becoming prey
  itself and thus having no more fitness)
• minimize its costs (like saving enough energy and
  time to find mates and to manufacture gametes,
  etc. and not losing its fitness as in passing the
  genes for this behavior into the gene pool)

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Why would fruit flies have two different
alleles for foraging behavior?
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Figure 47.8 lower
3. Collect eggs atrandom to comprisenext
generation50eggs in low-densityexperiment and
1000eggs in high-densityexperiment. Transferto
new medium.
4. Repeat steps2-3 for a total of
73generations. Observeforaging behavior ofa
sample of fly larvaefrom each population.
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Figure 47.3 upper
1. Start with fruit fly eggs homozygous for
sitter allele (fors).
2. Add extra copies of dg2 gene (of unknown
function) to treatment eggs, none to controls.
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Test article

• http//www.eurekalert.org/pub_releases/2003-10/uoi
  a-get100603.php
• 60 different bees who were working either as
  nurses (taking care of the brood within the hive)
  or foragers (gathering food outside).

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Complex behaviors evolve by combining and
mutating simpler patterns

• The case of crane courtship behaviors and their
  phylogenies is a powerful example for how complex
  behaviors can evolve. This example is analogous
  to many other studies explaining how complex
  morphological structures (eyes or wings, for
  example) or complex metabolic pathways (like
  photosynthesis) evolve from simpler components.
  Be prepared to outline the narrative of how the
  crane courtship most likely evolved.

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Figure 47.13b
Tree based on complexity of courtship displays
G. canadensis
G. leucogeranus
G. vipio
Bugeranus
G. antigone
G. americana
G. japonensis
G. monachus
A. paradisea
G. rubicundo
G. grus
G. nigricollis
Balearica
A. virgo
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Figure 47.13c
Tree based on DNA sequences
G. leucogeranus
G. canadensis
G. vipio
Bugeranus
G. antigone
G. americana
G. rubicundo
A. paradisea
G. monachus
G. japonensis
G. nigricollis
Balearica
G. grus
A. virgo
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Does this behavior increase this
individual's fitness?
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two alternative hypotheses to explain the
behavior of the second female in figure 47.10a

• kin selection, she's a close relative and we
  could determine their coefficient of relatedness.
  
• reciprocal altruism. She's learned that the
  mother might return the favor. Do individual
  animals in some species instinctively cooperate
  when they are likely to benefit somehow in the
  long run?

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Could true altruism exist?

• No A gene which results in death or
  disadvantage to its owner will not stay in the
  gene pool
• Yes kin selection could evolve into true
  altruism in very small populations if everybody
  had the gene.
• maybe

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Human altruism?

• Do we choose to decrease our own fitness, leaving
  others to make larger contributions to the gene
  pool?
• Are our choices true free will, or are our genes
  calculating coefficients of relatedness?

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Essay 47.1, Figure 1
Biological parent
Step-parent
600
600
500
500
400
400
Rates of homicide(victims per million
child-years of parent-child co-residence)
300
300
200
200
100
100
0
0
02
35
68
1214
1517
911
1517
1214
911
68
35
02
Age of child (years)
Age of child (years)
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CHOICES

• Nature and nurture both influence choices
• nature is stronger in lower animals
• more complex animals can learn so.
• Can human beings learn enough to have true FREE
  WILL?

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SEXUAL SELECTION

• Mate choice by
• females

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Does this behavior increase this
individual's fitness?
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Why do some people who have
suffered physical or emotional abuse as children
display violent behavior as adults, while others
do not?

• ( http//www.sciencemag.org/cgi/content/short/297/
  5582/851 ) the answer may lie in a complex
  interplay of genes and environment. The group
  found that a certain form of a gene that encodes
  MAOA, an enzyme that cleans up excess
  neurotransmitters in the brain, makes men more
  likely to be violent -- but only if they were
  abused as children.Previous studies have shown
  that low levels of MAOA activity increase
  aggressive behavior in both mice and humans.
  Caspi et al. followed the lives of 442 males (154
  of whom were physically or sexually abused as
  children) living in New Zealand for 26 years
  beginning from birth. Although only 12 of the
  men who had been maltreated as children displayed
  low MAOA activity, they accounted for 44 of the
  violent crimes committed by the group. On the
  other hand, children who were mistreated but had
  higher levels of MAOA were unlikely to develop
  behavior problems as adults, a finding that
  suggests that a particular MAOA genotype could
  protect maltreated children against aggressive
  behavior.

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Does this behavior increase this
individual's fitness?

• a single gene, Gp-9, that helps control how
  ants perceive pheromones and, thus, recognize
  queens. http//www.sciencemag.org/cgi/content/shor
  t/294/5546/1434
• Genetics of Fear http//www.sciencemag.org/cgi/con
  tent/short/297/5580/400 showed that people with
  different versions of a single gene have
  different patterns of brain activity in response
  to fear. The gene -- involved in transporting
  serotonin, a neurotransmitter known to modulate
  behavior and emotion -- comes in two versions, or
  alleles short and long. When asked to match
  pictures of frightened or angry faces, the
  patients with at least one short version of the
  gene showed greater activity in the amygdala -- a
  small structure deep in the brain that processes
  anxiety-related behavior -- than people with two
  long copies. also see http//www.sciencemag.org/cg
  i/content/short/297/5580/319a
• Are we wired to cooperate? Are we wired to
  believe in coincidence?
• Is biophilia genetic? (Are we wired to love
  field trips?)

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http//www.queens.edu/faculty/jannr/bio103/helpP
ages/c47behavior.htmLINKS

• do women choose older males? Or bigger males?
• Love is fundamentally more important--biologically
  speaking--than war.
• Is homosexuality genetic? Study finds chemical
  link to sex attraction --Male fruit flies court
  each other after brain alteration
• How altruistic are bird parents? How some birds
  choose their nest sites
• Why birds flock and fish school
• Brain injuries prevent normal ethical
  development?
• xenophobic brain activity

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Does this behavior increase this
individual's fitness?
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Darwin's four postulates

• Individuals have variations
• Variations are genetic
• only some offspring survive and reproduce
• Natural Selection survival and reproduction of
  the fittest.

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Does this behavior increase this
individual's fitness?
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MORE ABOUT

• Behavior http//www.queens.edu/faculty/jannr/bio10
  3/helpPages/c47behavior.htm
• Evolutionhttp//www.queens.edu/faculty/jannr/evol
  ution.htm
• Genetic Toolshttp//www.queens.edu/faculty/jannr/
  molecular/index.htmTOOLS

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Figure 47.2
FORWARD GENETICS
DNA
Food
Protein
Fly larvae rove after eating
Fly larva sits after eating
Function
Mutant locus
...ACCGTTACGGA...
Mutant
4. Identify the protein produced by the
gene. Investigate its function.
3. Clone and sequence the mutant gene.
2. Map the physical location of the mutant
locus.
1. Find a mutant that does not exhibit a
behavior.
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Figure 47.1a
Teen-onset alcoholism
Environmental predisposition? (foster parent
alcoholic)
Percentage of adopted boys who abused alcohol
as adults
Genetic predisposition? (biological parent
alcoholic)
1.9
NO
NO
NO
YES
4.1
YES
16.9
NO
YES
YES
17.9
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Figure 47.1b
Adult-onset alcoholism
Genetic predisposition? (biological parent
alcoholic)
Environmental predisposition? (foster parent
alcoholic)
Percentage of adopted boys who abused alcohol
as adults
NO
NO
4.3
NO
YES
4.2
YES
NO
6.7
YES
YES
11.6
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Box 47.1, Figure 1
REVERSE GENETICS
Normal mouse with 5-HTIA (low anxiety)
5-HTIA
Serotonin
Out
DNA
In
...CGGTAACGATTA...
5-HTIA
Mutant mousewith no 5-HTIA (high-anxiety)
5-HTIA protein serotonin receptor
1. Identify proteinwith knownfunction.
2. Infer DNA sequence of gene that codes
forthat protein.
3. Find and mutate locus, so protein is no
longer produced.
4. Study mutant individuals. Does their
behavior change?
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Figure 47.7
Female pairedwith male
100
Female with group of males
80
Female with groupof castrated males
60
All-female group
Percentage of females with mature follicles
Female alone
40
Females in natural(winter) habitat
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0
0
1
2
3
4
6
5
Weeks