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Neurological Basis of Behavior (PSY - 610)
VU
Lesson 06
EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR
Objective:
To understand
·  The Brain behavior relationships from the perspectives of biological systems.
·  The concepts of theory of evolution and its developmental process.
·  Evolution of the homosapien and to understand brain development and behavior changes.
Evolution:
As we have seen in the last lesson, the concepts of evolution were also evolving, Darwin has built on
what was already being thought about, but what makes his theory unique is what we are going to talk
about today
Theory of Evolution:
Darwin was the first one who actually gave the mechanism of how or why the process of evolution
takes place. The first premise being that there are limited resources and all living organisms compete for
the limited resources available. Therefore a struggle for existence is essentially a struggle for resources
and a struggle for survival.
Who wins the battle? Clearly the species which has even slightest advantage, (long neck for giraffes if
food higher up in the trees), will have the best chances for survival, and can continue to propagate under
hostile and competitive conditions. The best adapters are therefore the best reproducers and the best
reproducers are the ones best fit for survival.
Decent With Modification
Variation in genetic population provides a rough template for natural selection to work on (the variation
can also occur via mutation: change in chromosomal order or genetic code). Modification of genetic
variation takes place through natural selection.
What is Natural selection?
Natural selection affects all living organisms, in keeping a species strong and fit for existence under the
conditions in which it is living. NATURE SELECTS! Natural selection pressure s can work only in the
presence of genetic variability
Adaptations made in one generation, if beneficial would be carried on to the next generation there is
constant process of adaptation. If species do not adapt they do not survive (dogs which do not learn to
watch for cars on the road, die­which means the end of their genes). Primates developed extensions to
help in survival/hunting (young chimps use hollow sticks for ants), as they could not compete with the
stronger hunters and predators.
Genetic Variation: What is Genetic variation or phylogenetic inertia, these can be defined as basic
inherited properties in which there is a variation and can be changed and the extent they can. All
organisms have combinations of characteristics; however each has a unique combination. These
combinations can change.
Changes in the genetic combination can occur through a) combinations of different gene pools i.e.
interracial marriage or marriage of completely unrelated individuals b) mutations; these are changes in
the gene material through radiation or a genetic accident (or now genetic manipulation). These changes
would lead to a new and unusual combination of genes.
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Neurological Basis of Behavior (PSY - 610)
VU
Survival of the fittest: qualities which enable survival and further propagation in a hostile environment.
We are not talking of being healthy or physically strong but having qualities with which animals can
propagate successfully and offspring survive to continue to contribute to gene pool. The gene pool for
the next generation is better as weaker genes do not survive to contribute to gene pool. The fittest genes
live on, propagate and make up the upcoming successive generations.
What if we have a species doing very well, this would increase the number of surviving animals. This
would again lead to competition for food thereby struggle for existence would continue
Evolutionary adaptation and speciation: these are also evolutionary processes/ changes which a
species goes through to enhance its survival.
Evolutionary adaptation: there are two kinds of adaptations which can take place during the process of
evolution, 1) Centripetal: which means the organism would remain in the same state, for millions of
years as there are no environmental pressures to change. There is stability, and no change is beneficial
for survival. The animal does not change e.g. silver fish is the same for millions of years. 2) Centrifugal:
when there is a non stable environment with very rapid changes taking places, therefore rapid change in
the species occurs to survive. It is during centrifugal change that mutations occur in large numbers and
very rapidly as the selection pressures are intense.
Speciation: when the same species spread to different geographical locations, they evolve differently
into different species. The same birds in the sea would develop qualities of sea- birds, those which go up
into the hills would develop characteristics needed for survival in the hills.
Isolation: whenever a species was geographically isolated and there was no competition, theses would
evolve into different species depending on the locations (divide territory for mutual benefit).The animals
in Australia, and Galapagos are good examples
Adaptive radiation: adaptive process where the same species develops different characteristics. In
Australia the marsupials radiated into different species such as tasmanian cat, koala (trees), duckbill
(water), kangaroo (land) spreading and foraging across grass, tree, water, hill, land),
Evolution: Mammalian, Primate To Homosapien
The first major phase in evolution is speculated to be when fishes move on to land, they evolved
into amphibians dinosaurs. The dinosaurs ruled earth in various forms they were huge, physically
but had very small brains. At about the end of reptilian era a very small mammalian species
evolved: a) it had a fur coating for thermoregulation b) had strong olfaction (brain grew-due to
olfaction?) c) better hearing (had to compete with large animals so had to forage in the dark)-bones
in jaws moved to side to form ear bones, d) Vision gradually highly evolved for higher primates
Mammalian evolution began with the monotremata these were egg layers like reptiles but were fur
bearing and nursed their young (this led to attachment­ benefit for survival teaching young to
survive. young to stay with mother till they are out of vulnerable stage).
Advantages: instead of having 10 eggs and have none survive (open to predators), have one (major
investment which develops slowly and lives to propagate). POPULATION GROWTH SLOW BUT
STEADY
This also brought about change in the maternal role. : The young suckles and stays with mother,
Purpose of such a development, a) nurturance provided directly so that there is fitness, b) learning
directly form an adult: Learns to run when mother does, to eat what she does, c) is protected from
all bigger and more dangerous animals by the adult ( mother: maternal aggression is well
documented).  Thus, early development became and important period where attachment and
bonding began. This is a sensitive period where the young is tied to the mother through pheromonal
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Neurological Basis of Behavior (PSY - 610)
VU
signals. The highest form of attachment bonding with mother developed in primates
Human Evolution
·
Hominids evolved into at least 7 different species their names specify the location their remains
were discovered in: Australopithecus ( about 2 -3 million 500 cc brain ), Java ( Indonesia), Peking
( China), Olduvai man ( in the Olduvia Gorge in Africa), Pithecanthropus, Homo Erectus,( brain
size about 900 cc) Neanderthal (brain 1400cc) ( Germany), Cro-magnon
·
Pithecanthropus: the earliest man-ape who was cage living, used stone tools. There is evidence in
the cages of use of FIRE (therefore fire had been discovered). There is also evidence of
cannibalism, especial favourite appears to be the brains (cracked cranium is evidence for such
activity). There appears to be family and some social groups.
·
Neanderthal: remains found in the Neander Valley in Germany. The evidence indicates that the
Neanderthal was present around 1, 00,000 to 50,000 years. In appearance they were small and
heavy set, brutal looking, slightly larger brain size but very efficient brain compared to earlier
species. This was the beginning of a man shaped like an ape. There is increased tool use with
specialized tools for cutting, piercing, shaping. This ape-man migrated by traveling across as
indicated by the finds of remains which are spread over Europe, Africa, and Near East.
Reference
Pinel, John P.J. (2003) Biopsychology (5th edition) Allyn and Bacon Singapore
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Table of Contents:
  1. INTRODUCTION:Descriptive, Experimental and/ or Natural Studies
  2. BRIEF HISTORICAL REVIEW:Roots of Behavioural Neurosciences
  3. SUB-SPECIALIZATIONS WITHIN THE BEHAVIORAL NEUROSCIENCES
  4. RESEARCH IN BEHAVIOURAL NEUROSCIENCES:Animal Subjects, Experimental Method
  5. EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR:Species specific
  6. EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR:Decent With Modification
  7. EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR:Stereoscopic vision
  8. GENES AND EXPERIENCE:Fixed Pattern, Proteins, Genotype, Phenotypic
  9. GENES AND EXPERIENCE:Mendelian Genetics, DNA, Sex Influenced Traits
  10. GENES AND EXPERIENCE:Genetic Basis of behavior, In breeding
  11. GENES AND EXPERIENCE:Hybrid vigor, Chromosomal Abnormalities
  12. GENES AND EXPERIENCE:Behavioral Characteristics, Alcoholism
  13. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION
  14. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION:Activating brain
  15. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION:Macro electrodes
  16. RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION:Water Mazes.
  17. DEVELOPMENT OF THE NERVOUS SYSTEM:Operation Head Start
  18. DEVELOPMENT OF THE NERVOUS SYSTEM:Teratology studies, Aristotle
  19. DEVELOPMENT OF THE NERVOUS SYSTEM:Stages of development, Neurulation
  20. DEVELOPMENT OF THE NERVOUS SYSTEM:Cell competition, Synaptic Rearrangement
  21. DEVELOPMENT OF THE NERVOUS SYSTEM:The issues still remain
  22. DEVELOPMENT OF THE NERVOUS SYSTEM:Post natal
  23. DEVELOPMENT OF THE NERVOUS SYSTEM:Oxygen level
  24. Basic Neuroanatomy:Brain and spinal cord, Glial cells, Oligodendrocytes
  25. Basic Neuroanatomy:Neuron Structure, Cell Soma, Cytoplasm, Nucleolus
  26. Basic Neuroanatomy:Control of molecules, Electrical charges, Proximal-distal
  27. Basic Neuroanatomy:Telencephalon, Mesencephalon. Myelencephalon
  28. Basic Neuroanatomy:Tegmentum, Substantia Nigra, MID BRAIN areas
  29. Basic Neuroanatomy:Diencephalon, Hypothalmus, Telencephalon, Frontal Lobe
  30. Basic Neurochemistry:Neurochemicals, Neuromodulator, Synaptic cleft
  31. Basic Neurochemistry:Changes in ionic gates, The direct method, Methods of Locating NT
  32. Basic Neurochemistry:Major Neurotransmitters, Mesolimbic, Metabolic degradation
  33. Basic Neurochemistry:Norepinephrine/ Noradrenaline, NA synthesis, Noadrenergic Pathways
  34. Basic Neurochemistry:NA and Feeding, NE and self stimulation: ICS
  35. Basic Neurochemistry:5HT and Behaviors, Serotonin and sleep, Other behaviours
  36. Basic Neurochemistry:ACH and Behaviors, Arousal, Drinking, Sham rage and attack
  37. Brain and Motivational States:Homeostasis, Temperature Regulation, Ectotherms
  38. Brain and Motivational States:Biological Rhythms, Circadian rhythms, Hunger/Feeding
  39. Brain and Motivational States:Gastric factors, Lipostatic theory, Neural Control of feeding
  40. Brain and Motivational States:Resting metabolic state, Individual differences
  41. Brain and Motivational States:Sleep and Dreams, Characteristics of sleep
  42. Higher Order Brain functions:Brain correlates, Language, Speech Comprehension
  43. Higher Order Brain functions:Aphasia and Dyslexia, Aphasias related to speech
  44. Higher Order Brain Functions:Principle of Mass Action, Long-term memory
  45. Higher Order Brain Functions:Brain correlates, Handedness, Frontal lobe