Transcript Genetics of Animal Behaviour

Animal Behaviour
INTRODUCTION
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Animals behave in
different ways:
- HOP
-RUN
- WALK
- SWIM
- FLY
- BURROW
- CRAWL
INTRODUCTION
Many engage in complex
rituals for attracting mates
- employ tricks for finding
food, avoiding enemies
and raising their young.
- They build spider webs,
beehives, coral reefs, bird
nests, and beaver dams to
provide shelter and to
obtain and store food
INTRODUCTION contd.
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There are no genes that directly code for behaviour,
- play a role in behaviours.
Animal beahaviour
- influenced by the external environment.
through development of nervous and hormonal mechanisms.
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Majority of the behaviour observed in animals is adaptive.
EVOLUTION
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All species have descended from a common ancestor (C.A)
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Evolutionary changes of species from their ancestral forms
may have resulted in behavioural changes of the species.
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Evolutionary changes are studied
- phylogeny
- comparison of the behaviour patterns of species
descended from a recent C.A
EVOLUTION contd.
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Evolution is due to natural selection.
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Natural selection favours,
- animals that leave more offspring than the average
for their species.
- hence behaviour of animals adapted to their
environments.
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Behavioural evolution is gradual
- gradual accumulation of many small adaptive changes,
result in the formation of traits that differ
greatly from the ancestral characteristic.
APPROACH TO ANIMAL BEHAVIOUR
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The cause of behaviour is understood, in the four levels of
analysis:
- proximate or immediate
- ultimate or long-term causes of behaviour
Proximate and ultimate causes are interrelated.
naturally selected genotype can exert proximate
influences over individual’s development, affecting:
- nature of the mechanisms = enables it to do
certain things.
APPROACH TO ANIMAL BEHAVIOUR
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Development of any trait - result of G X E interaction.
Environment = material environment and experiential
environment.
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Genes to respond to environmental signals- altering activity
= to changes in the gene products.
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Behavioural differences – genetically or environmentally
determined
APPROACH TO ANIMAL BEHAVIOUR
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Behavioural development has adaptive features:
(1) development of homeostasis
(2) Developmental switch mechanisms
(3) Learning mechanisms
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Learning reflects past selection for capacity to make
adaptive adjustments in behaviour that match the
environment of the individual
NEURAL MECHANISM AND
HORMONES
 Behaviour is controlled by the nervous system, which is
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made up of neurons and operates electrically and
chemically.
Neurons are connected with each other at synapses which
enable the control of flexible and complicated behaviour.
Hormones - chemicals that re released by certain organs
that influence other organs in the body.
Hormones can increase, or decrease, the chance that
particular behaviour patterns will be performed
NEURAL MECHANISM AND
HORMONES
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Animal’s environment provides various stimuli that could trigger
contradictory responses, and because its physical and social
environment often changes over time, animals gain by having
mechanisms that set priorities for different behavioural options.
Such as behavioural centres that have the capacity to inhibit one
another, so that animals do not try to do several things
simultaneously.
Nature of the inhibitory relationships between neural command
centres is influenced by the environment,
- environment changes they also change,
hence they are detected by neural mechanisms
and then translated into hormonal messages.
DEVELOPMENT OF BEHAVIOUR
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Majority of the behaviour observed in animals is adaptive.
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They respond to appropriate stimuli in an efficient manner,
-feed themselves
-find shelter
-mate and rear families
DEVELOPMENT OF BEHAVIOUR
Learning, Memory and Communication
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Learning:
- Associative
- Non-Associative
* habituation
* sensitization
Learning, Memory and Communication
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Non-associative learning also known as conditioning
two forms:
- classical conditioning
e.g. Pavlov dogs and in courting gouramis
- operant conditioning
e.g. pigeons learning to peck at disks in order to
obtain food
DEVELOPMENT OF BEHAVIOUR
Birds Characteristic Song
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Bird species associated
with its own distinctive
song
- Adaptation
e.g. ovenbird sings
“teacher-teacher-teacher”
Birds Characteristic Song
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Song learning dependant - genetic information
- environmental contribution
Two phases to learning a song
- memory phase
- practice phase
MIGRATION
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Migration is any pattern
of movement (back and
forth) by living things
between TWO relatively
distinct LOCATIONS.
e.g.
Mass movement of herds
of wildebeest
MIGRATION
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Seasonal migrations of
birds
- SWALLOWS
- BUTTERFLIES
MIGRATION
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Each Breed - SPECIFIC as to which habitat it resides.
Favourable environments:
- sufficient food
- correct type food
- correct temperature and habitat
- reduced number of animals inhabiting that
environment
- no parasitises and predators
MIGRATION
WHY DO ANIMALS MIGRATE?
 locate SUPERIOR environments
- requires mechanism
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Mechanisms vary - sensory range
e.g. Wildebeest
rely on sensing distant rainfall using eyes and
ears therefore migrate in that direction.
SEXUAL BEHAVIOUR
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Reproduction
- mate with correct species
- competition to court (attract)
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Courtship - behavioural interaction of the male and female
that leads to fertilisation of eggs and sperms.
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Darwin’s Theory:
- States in most species, males compete for, and
females select, mates
SEXUAL BEHAVIOUR contd.
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Males compete for females,
- physical fighting
- subtle invisible competition among sperm within the
female reproductive system.
Mate choice by females occurs in species
- Males provide no material benefits.
Selective females - gain by securing genes that enhance the
viability of their offspring
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E.g. Female choice:
extravagant and probably
deleterious male traits such
as the peacock’s tail.
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Through experimentation,
female prefer males with
longer than average tails
CONCLUSION
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Animal behaviour is not caused by the animal’s genes or by
its environment alone, but by G X E interaction.
-Determines how an animal will behave.
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The animal's nature is influenced by both genetics and
learning.
The End!