Transcript PerspectivesNotes07

Animal Behavior
Perspectives of
Behavior
Ethology Sponge #1
Behaviors always have a cause usually caused by
a stimulus.
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Proximate Causes of behavior are those stimuli that
directly cause a behavior.
Ultimate Causes of behavior are those causes that help
in the “ultimate” survival of a species.
Explain each of the following human behaviors in terms
of their proximate AND ultimate causes:
Walking and Running
Eating
Arguing with a friend
Flirting with a boy or girl
Getting nervous before a big event-a game or interview
Ethology
Ethology is the the study of the behavior of
animals and the proximate and ultimate
causes to those behaviors
Ethological studies require comparisons
between a variety of species whose
morphology, behavior, and ecology are
diverse.
– All behaviors reflect the range of solutions which
have evolved to meet the needs of the organism in
their given environment.
Quic kTime™ and a
TIFF (Unc ompres sed) dec ompres sor
are needed to see this pic ture.
Quic kTime™ and a
TIFF (Unc ompres sed) dec ompres sor
are needed to see this pic ture.
Terms in Review
Some basic Biological terms in review from this
type of study include:
- Morphology - refers to the study of the similarities in
structure and function of living organisms (example:
the hand and the fin and the wing)
- Ecology - refers to the study of the interaction between
a living organism(s) and the environment.
- Behavior - is defined as an objective and mechanistic
description of acts without reference to function.
- Stimulus - anything that causes an animal to respond
- Response - an action caused by a stimulus
Ethology, Morphology and
Taxonomy
Since ethology is a comparative study of
behaviors it’s important to know how we
compare
Morphology is the study of the similarities and
differences in living things (in this case how animals
behave)
– A part of morphology is being able to relate animals to
each other using classification
Taxonomy is the study of morphological similarities
and differences and their relatedness (classification)
Activity
- Taxonomy & Morphology
Cladistics is a type of classification
scheme used in taxonomy
– Similarities (synapomorphy) & differences
(pleisiomorphy) are used to create a type of
family tree
Pick any three animals that you know
about and create a Cladogram of their
behaviors diagraming synapomorphies
and pleisiomorphies for each
Basic Needs & Behavior
All behavior satisfies one of the basic needs
of all living things.
1. Finding food
2. Not becoming food
3. Sexual reproduction
Each behavior has a cost-benefit (what it gets
versus what it costs) component to it.
Consider the three basic needs for animals. Pick
any two animals and discuss the cost benefit for
each in nature
Proximate Causes
Proximate causes are immediate causes for a
behavior
– Proximate causes refer to those "closest" to the
behavior
Proximate Causes have three components of activation
for animals: Input, Integration and Output
– Animals are not like computers (input  output)
– Input is usually a stimulus, integration is how the
animal internally processes the stimulus and output
is the response to the stimulus
Ultimate Causes
Ultimate Causes are autonomic responses in organisms
– Autonomic = automatic (you respond quickly and without
hesitation, thought or consideration)
Ultimate causes are evolutionary processes that are successfully
reproduced in organisms over time
– Adaptation is a process by which groups of organisms maintain
change what they do and/or how they do it or die
Evolutionary processes are caused by mutations, which provide
variation, and selection, which determines the variations that are
preserved and perpetuated
Behavior is subject to evolution.
– Behavioral changes (for example, the development of a new
food preference or mode of foraging) can be a first step of
evolutionary adaptation, followed by the natural selection of
appropriate changes in body form and other characteristics
Controls to Behavior
Controlled by interactions between the
environment and lineage
The environmental interaction refers to the
successful expression and reproduction of
a trait over time
Lineage refers to the heritable information
gained from parents, grandparents
(ancestors) that make each organism
unique
Environmental Interactions
As organisms interact with biotic and abiotic
factors in the environment behavior is produced
– Biotic factors = other living things
– Abiotic factors = non living things
Behaviors produced are either good or bad for
the organism
– Some behaviors may get an organism killed and
some may help the organism survive in the
environment and further respond to biotic and abiotic
factors in the environment
Successfully passing on behaviors through
reproduction = evolution
Perspectives of Behavior
Perspectives are ways of studying behavior
– Each perspective has a specific field of biology as its
target
– Each perspective asks different questions and have
different methods of answering them
– Each perspective is appropriate to the level of
organization that is being studied, but they are all
studying behavior and the consequences of behaviors
Prospective Fields:
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Developmental Perspective
Ecological Perspective
Evolutionary Perspective
Physiological Perspective
Physiological Perspective
The biological needs of the organism through it’s expression of a
behavior that affect it’s internal chemistry and thus it’s outward
expression.
NEUROBIOLOGY involves the nerves and their activities, how they are
linked together to transmit information through the organism for specific
purposes. For convenience we sometimes distinguish INPUT,
INTEGRATION, and OUTPUT .
– INPUT involves the senses -- the only way we can get information about the
always changing environments in which we must function;
– INTEGRATION involves how the the brain regulates motivation, affect, and
cognition to cause behavior (various bits of information are encoded in the
nervous system and interact with each other to affect behavior)
Within the integration component we will distinguish three systems that
overlap significantly but are in general responsible for fundamental aspects
of behavior: MOTIVATION, AFFECT, and COGNITION.
– OUTPUT involves the actions of the nervous system on "effector" organs that
accomplish its goals such as endocrine glands and muscles
Developmental Perspective
Study of the behavioral development over it’s lifetime
– Changes in individuals - becoming "all you can be” - involves the
progressive expression of genetic potential
ONTOGENY has to do with the sequential expression or unfolding
of the genetic potential in a protected environment such as the
womb or an egg.
EXPERIENCE has to do with expression of genetic potential in the
environment an animal finds itself, such as after birth
– changes in behavior occur as a result of experience is learned either
through non-associative or associative processes
EPIGENESIS it the term used for the unfolding of genetic potential
as a function of its interaction with the environment
– Specific experiences are more-or-less potent in activating specific
genes or facilitating specific parts of the path from gene activation to
the eventual expression of a trait.
Ecological Perspective
The contexts in which individuals function-climate,
geology, and other animals
– involves the context in which behavior occurs and the
organism's interactions with the environment
ENVIRONMENT involves the ecosystem and all its time
or spatial dimensions:
– climatic variables such as moisture and temperature, other
organisms --predators, prey, companions, mates, etc.
– Environmental thinking sometimes helps us understand the
organism's inner environment --blood chemistry, endocrine
tone, hunger, experience of various physiological needs.
Rhythms, cycles, present and past environmental fluctuations
Evolutionary Perspective
A perspective is a way of looking at a behavior.
The evolutionary perspective considers both the ultimate cause and
the evolution of a species due to those ultimate causes.
– Remember that evolution is the study of change across
generations and the "ultimate cause" of behavior.
– Involves biological variations that affect changes in traits.
– Comparative behavior pattern seen in relatives over time that aid
in the survival of the species over generations
Since behavior is controlled by genetics it is important to know the
following:
– GENES - biological units of inheritance
– MEMES - cultural units of inheritance
– FITNESS - number of successful offspring, capacity to project
"biologically relevant information" (such as genes or memes)
into the next generation
Natural Selection &
Darwinian Theory
Charles Darwin was a naturalist that suggested biologically
relevant information is transmitted from generations on he
said the following:
Variation within a species - Variation exists between
individuals in a species
Heritability - Organisms produce more offspring than
environment can support
Adaptation - Competition exists between individuals and
those individuals that adapt will survive
Natural Selection - biotic and abiotic factors will affect
individuals allowing them to reproduce successfully or not
Organisms whose variation best fit them to the
environment are the most likely survive, reproduce and
pass those desirable variations to the next generation
Selection Modes
Selection is defined as a relationship between fitness
and phenotype
Fitness is defined using terms of three kinds of
SELECTION MODES:
– directional selection in which a trait is linearly related to
fitness,
– Stabilizing or convergent evolution is when there is an
optimal value for the trait of interest, and
– disruptive or divergent evolution is when there are
individuals with the smallest and largest values of the trait
have the highest fitness and individuals with intermediate
traits are at a fitness disadvantage.
Selection Modes
Selection Modes
Directional Selection - favors individuals
possessing extreme values of a trait (like
long necks in giraffes, coloration in
peppered moths), which causes the
population to move in a particular
direction.
– Example: If a climate becomes colder,
a population may evolve in a consistent
direction in response - thicker fur
Selection Modes
Stabilizing Selection - acts against
individuals who deviate too far from
the average, favors the average.
– Example: sizes in lizards: large
lizards may be subject to
predation, small lizards have a
hard time defending territories,
natural selection favors the
average
Selection Modes
Disruptive Selection - adapts individuals in a
population to different habitats. Its similar to
directional selection, but it favors either
extreme, not just one extreme. Disruptive
selection may occur in an area that provides
different resources.
– Example: Galapagos finches had a variety of food
choices, smaller birds fed on small seeds, larger
birds fed on large seeds, natural selection favors
both the large and the small bird, but not the
average bird (who would compete for both
resources)
Sexual Selection
Charles Darwin distinguished sexual selection as
a variance in the number of mates.
Sexual selection acts to refine characters in the
phenotypes between males and females types.
The action of sexual selection can take the same
three modes that are discussed on the previous
slide for natural selection.
– Directional, stabilizing or disruptive selection.
Smoke-Detector Principle
Some evolutionary processes produce traits that
appear as false responses or behaviors
Smoke-Detector Principle - behavioral response an
organism produces false response to a stimulus
– The intent - produce same response every time hoping that
once the “real” situation comes, the respond does not cost
your life
• The cost of responding to 100 false alarms is better than the cost
of losing life
– Human emotion is an example
Explain how the following two human emotions can
serve as a “smoke detector principle” for humans?
– An infant that cries when they get hungry
– You get scared, someone startles you and you scream and
jump
Principles of Evolutionary
Thinking
Thoughts on disease, evolution and behavior
Modern epidemics are most likely to arise from the
mismatch between PHYSIOLOGICAL DESIGN of our
bodies and NOVEL ASPECTS of our environment
Our DESIRES, shaped in the ancestral environment to
lead us to actions that tended to maximize reproductive
success, now often lead us to disease and early death
Some GENES that cause disease may also have
benefits, and others are quirks that cause disease only
when they interact with novel environmental factors
Principles of Evolutionary
Thinking
GENETIC SELF-INTEREST will drive an individual's actions,
even at the expense of the health and longevity of the
individual created by those genes
SYMPTOMS of infection can benefit the pathogen, the host,
both or neither
Disease is INEVITABLE because of the way that organisms
are shaped by evolution
Each disease needs a PROXIMATE EXPLANATION of why
some people get it and others don't, as well as an
EVOLUTIONARY EXPLANATION of why members of the
species are vulnerable to it
Diseases are not products of natural selection, but most of
the VULNERABILITIES that lead to disease are shaped by the
process of natural selection
Controls to Behavior II
Remember that behavior is controlled by two things
– Environment and genetics (heritable traits)
Natural Selection from the level suggests the following:
– Variation - Members of a species may differ in their
characteristics. Alternate alleles for characteristics
exist in nature (tall versus short).
– Heredity - Alleles for a characteristic can be
transmitted from parent to offspring by sexual
reproduction.
– Differential Reproduction - Some alleles are better at
causing bearers to transmit copies of those alleles to
offspring better than others.
Heritable Traits
DNA = Deoxyribonucleic acid
– The genetic code (genotype) for all living things
transcribed through development into the physical
being (phenotype) we call an animal
DNA inherited from parents (the survival of a
trait transmitted)
– Essentially if you reproduce before you die, you
transmitted your traits on to your child (=offspring)
DNA make up chromosomes that are
transmitted during sexual reproduction
Genes Control Behavior
A gene is a segment of DNA (an allele) that
controls the phenotype of an animal
– A phenotype is a behavior in this case
Animals have 20 or more chromosomes
and each chromosome contains more than
100 genes.
– Each gene controls a different phenotype
– Genes interact in complex ways to make
complex organisms with complex behaviors
Basic Genetics
Every animal inherits chromosomes from
each parent
– Half of your chromosomes come from each
parent to make you the whole individual
Animals are therefore hybrids (a cross
between their mother and their father)
– The assortment of the traits that animals get
from each parent make each animal unique
genetically (genotypically) and physically
(phenotypically)
Genes and Populations
Mutations - Random changes in genetic sequence
causes changes in phenotype
Gene Flow - Mutations can dominate in a population
because of environmental variables thus pushing
more individuals in the population through
reproductive fitness levels to express a specific trait.
Genetic Drift - Movement of traits into a population
thus focusing the gene pool of the population into one
direction
Non-Random Mating - Mating preferences and
selection of mates predisposes populations to
express some traits over others.