Animal Behavior and Its Evolution

1
Chapter 51

• Animal Behavior and Its Evolution

2
The Genetic Basis of Behavior

• Behavior has its roots in the genetic program
  carried in the DNA molecules.
  
• Walter Rothenbuler, in his experiment crossing
  unhygenic and hygenic bees, discovered that the
  unhygenic trait was dominant.
  
• A single allele may determine a particular
  behavioral characteristic of an organism.
  
• Most often, behavioral characteristics are a
  result of plygenic inheritance they depend on
  the integrated action of alleles of a large
  number of genes.

3
Proximate and Ultimate Causation

• Proximate cause the immediate sequence of
  physiological events that lead to the observed
  behavior.
  
• Ultimate cause adaptive value and evolutionary
  origins
  
• Individuals with a highly efficient response are
  more likely to avoid predation and thus to
  survive maturely and successfully reproduce.

4
Fixed Action Patterns

• Some behavior patterns develop within a minimum
  of sensory experience
  
• Fixed action pattern a pattern that appears even
  after responding to a stimulus for the first time
  
  
• Releasers stimuli act as communication signals
  between two species.
  
• Innate releasing mechanism certain specific
  areas in the brain that respond to the stimuli.
  
• In most cases, once a fixed action pattern has
  been initiated, it cannot be altered, but must be
  carried through to completion.

5
Learning

• All patterns of behavior depend on environmental
  cues and on normal physiological developments of
  the animal.
  
• Learning a process in which the responses of an
  organism are modified as a result of experience.
  
• The capacity for learning in loosely correlated
  with the length of the life span and with the
  size and complexity of the neural circuitry.
  
• Habituation a situation in which an organism
  comes to ignore a persistent stimulus and go on
  about its other business.

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Associative Learning

• One type of stimulus comes to be linked, through
  experience, with another one.
  
• 1st scientific studies of association performed
  by Ivan Pavlov in the 1920s
  
• Unconditional stimulus triggers unconditional
  response and a conditional stimulus triggers a
  conditional response.
  
• Associative learning involves trial and error,
  this is known as operant conditioning, since the
  animal learns through operational experience to
  associate its behavior with the consequences of
  its behavior.

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Imprinting

• Development of discrimination
• In many species, particularly birds, this
  learning occurs rapidly during a specific
  critical period in the early life of the
  individual and depends on the characteristics of
  the parents.

8
The Song of the White-Crowned Sparrow

• As the white crowned sparrow grows older, its
  song becomes more complex
  
• For the song, three requirements must be met (1)
  the bird must have the genetic capacity to
  recognize and reproduce the song (2) must hear
  the song during the critical period for
  imprinting (3) must be able to hear himself sing
  the song.

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Imitative Learning

• Some of the most dramatic examples of learning
  through imitation have occurred in response to
  human activities.
  
• Monkey see, monkey do.

10
Social Behavior An Introduction

• The most intriguing behaviors are the the
  interactions that occur between animals.
  
• A society is a group of individuals of the same
  species, living together in an organized fashion,
  with divisions of resources, divisions of labor,
  and mutual dependence.
• Altruism behavior that benefits others and is
  performed at some risk or cost of the doer.
  
• Selfish behavior increases fitness for the doer,
  but not for the recipient.
  
• Cooperative behavior increases fitness for both.
• Altruistic behavior is the opposite of selfish.
• Spiteful behavior decreases fitness for both.

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Insect Societies

• Among the most ancient of all societies and are
  the most complex.

12
Stages of Socialization

• Most living species of bees and wasps are
  solitary.
  
• Among these species, the female builds a nest,
  lays her eggs, and usually dies soon after.
  
• There is no overlap between generations.

13
Honey Bees

• Population of 30000 to 40000 workers and one
  adult queen bee.
  
• Each worker, always a diploid female, begins life
  as a fertilized egg deposited by the queen in a
  separate wax cell.
  
• Drones, or males, develop from unfertilized eggs
  and are therefore, haploid. This phenomenon is
  know as haploidiploidy.
  
• Queens become queens because of a generally more
  nutritious diet in the larval stage, especially
  rich in protein, unlike the mostly carbohydrate
  diet of the worker bee.
• The queen exerts influence on her worker bees by
  means of pheromones. This process prevents sexual
  maturation in her workers, which, in turn does
  not allow them to become queens.

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Vertebrate Societies

• Vertebrate societies dont usually have the same
  caste systems of truly social insects.
  
• Dominance hierarchies are maintained by patterns
  of behavior. A pecking order is established with
  a sometimes bloody spectacle, but once concluded,
  a simple nod of the head (ritualization) restores
  harmony in a group of a species such as hens.

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Territories and Territoriality

• Areas defended by individuals or groups against
  other individuals or groups are called
  territories.
  
• This characteristic of behavior is known as
  territoriality.
  
• This behavior was first recognized by bird
  watcher, Eliot Howard.

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Kin Selection

• Individuals that failed to reproduce were doing
  so for the benefit of society to which they
  belonged. This way a society can maintain a
  population level slightly below the amount of
  resources.
• Alleles for breeding dominate alleles for
  anti-breeding, however.
  
• Kin selection is the differential reproduction of
  lineages of related individuals that is,
  different groups of related individuals of a
  species reproduce at different rates.
• Inclusive fitness relative number of an
  individuals alleles that are passed on from
  generation to generation.

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The Selfish Gene

• The organism is the genes survival machine, and
  it programs the machine so that it will turn out
  copies at maximum rate.
  
• The individual organism is transient.
• Samuel Butler remarked that a chicken was just an
  eggs way of making another egg.

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Conflicts of Interest

• Survival of genes rather than individuals.
• Conflicts can not only occur between those
  individuals that were in obvious direct
  competition for some limited resource, but also
  among individuals previously envisaged as working
  together for a common good.
• Male vs. Female the intense competition may
  arise among the males to prove to the females
  that they are the best endowed.
  
• In some few species, males make a contribution to
  the care of the young if this additional parental
  attention would result in significant increase in
  survival or that the male has some way of being
  sure that the offspring he cares for are his own.

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The Advantage of Waiting

• An animal that is not breeding because it is low
  in the hierarchy or lacks territory may not be
  sacrificing itself, but may be waiting for its
  chance to move up in the pecking order to gain
  influence before offspring.
• An individuals chances of perpetuating its
  genotype are better than if it challenges a
  superior and is killed or badly injured.

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Reciprocal Altruism

• Altruistic acts may pay off because they increase
  probability of survival of genes shared by the
  performer if the act.
  
• Reciprocal altruism an act is performed with the
  exception that the favor will be returned.
  
• For reciprocal altruism to be a successful
  strategy that is resistant to exploitation by
  individuals who accept the favors but never
  return them, two conditions are necessary (1)
  individuals meet more than once and are able to
  recognize each other, (2) each individual
  cooperates on the encounter and does whatever the
  other individual did on the proceeding encounter.

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The Biology of Human Behavior

• One group of biologists maintains that the human
  species is basically no different from any other
  species, that our genes are selfish as any and
  that if we seek to modify human behavior for the
  common good, we should understand its roots.
• The notion that our behavior is biologically
  determined allows us to forgive ourselves for
  violence, aggressiveness, docillity and greed.