EVOLUTIONARY AND GENETIC BASIS OF BEHAVIOUR:Species specific

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Neurological Basis of Behavior (PSY - 610)

Lesson 05

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.

· Where is the genetic programming of behavior ( if any) and what are the similarities and

differences between species, progenies of higher order animals, including homosapien?

Evolutionary and genetic basis of Behavior

These lectures would take the students through Evolution of the brain, evolution of mammalian species,

the evolution of man, links with brain development. Classification on the phylogenetic scale, similarities

across the phylo-genetic scale, development of the concept of evolution, the Lamarkian, and Darwinian

theories, concepts of natural selection, survival of the fittest, speciation and adaptation, how gene

transmission take place, the double helix Watson and Crick model of the components of genetic material

and process of transmission.

Also the nature nurture debate with Ethologist and Sociobiolgists (based on Darwinian evolution) and

Experimentalists.

Man: defined in biological terms as Homosapien is a comparatively newly evolved species, with a

biological presence of not more than 50,000 years.

There are several distinctive characteristics of the homosapien:

a) The only animal with an upright walk and true bipedalism. This is an extremely complex

development, as it needs changes in the pelvic bones, the vertebral column, the cranium placement on

the top of vertebral column, the visual system etc. man can cover long distances without losing stamina

or strength to hunt.

b) Language as an "integrated system",. It is more learned, more refined communications where

combination of sounds and intonations are used in a sophisticated system. All cultures and tribes have

their own language. Humans have a specialized cortical area for language.

c) Specialized hunter-gatherer roles differentiating according to biological functions for male-females.

The females have greater responsibility of looking after the offspring and stay with the young while

males foraged.

d) Domestication of other animal's specialized abilities to benefit his survival (camels, horses, cows,

dogs, chickens).

e) Highly evolved and complex societies.

f) Kills own species without biological benefit, warfare and murder in other animal's species specific

survival purpose.

g) Highly evolved abstract thinking, aesthetics, tools painting in primitive caves. However, homo

sapien is similar to other biological species as can be seen through the taxonomic classification.

Neurological Basis of Behavior (PSY - 610)

Taxonomic Classification:

All animals in the animal kingdom categorized into this classification, which categorize animals from

general to specific. For example for homosapien we can see how this classification works

Kingdom---Animalia: most general, all animals on the face of the earth

Phylum: Chordata (notochord, pharyngeal gill slits )

Subphylum: Vertebrata ( vertebrate column)

Class: Mammalia

Carnivorous, herbivorous, omnivorous

Order: Primate

Family: Hominids, (for humans)

Genus: Homo

Species : Sapien

Species: Basic to classifying animals, usually clear and apparent difference between species.

Phyletic scale: a scale ordered in terms of differential characteristics

Species specific: Differences in appearance, shape and form- horse donkey, zebra come from the same

family EQUUS but different species. All three are herbivorous with similarities in behavior and

appearance yet there are differences. A horse may kick like a donkey, but is more territorial.

Class: vertebrates that bear their young and suckle them (humans belong to this category).

Order: What they forage/ hunt flesh/vegetable eating.

Species don't Inter breed (not in the naturally occurring circumstance), not because they are incapable

of doing so but for reasons unknown (answer lie sin genetic fitness). Cross mating is not biologically

beneficial as the genes are not propagated any further. Biologically, this is not a fit response. The case

of cross breeding of Horse and ass equals mule (sterile), fit for human as beast of burden but not for

wither species as this would be the end of the genes of the horse, the ass and the mule

Evolution of Evolutionary theories

Linneas: believed that animals were created as one act of creation, and that species fixed and

unchanging, variation within species possible however each species independent in its creation.

Comte Georges Du Buffon 1707-1788. Degeneration one species become another- concept of change?

Degeneration of monkey into man- effect of environment, forces of migration, environmental variation,

and struggle for existence introduced concepts used by Darwin later

Lamark 1744-1829 wrote the book Philosophie zoologique presenting his views. The concept of

Transmutation given by him was that animals are in a constant state of flux, constantly being perfected

and the direction of change is towards higher forms; Lamarkian change gives a ladder of life where

animals move upwards to higher forms and dead material returns to regenerate.

Change not fixity of species was elaborated for the first time and that the environmental pressures bring

about small heritable changes. Organs grow and shrink from use. Concept of use and disuse was also

given by him

Lysenko: gave his theory of inheritance of acquired characteristics, where he proposed that if there were

some changes made in one generation they would be passed on to next generation.

Neurological Basis of Behavior (PSY - 610)

Darwin: 1809-1882: traveled to the Galapagos Island on the HMS Beagle. His nine famous voyages

over 22 years were actually very well documented evidence of the animal species he saw on those

islands. His meticulous observations and notes, led him to see some patterns in similarities and

differences in the appearances, behavior and other patterns wrote the book "Origin of species" on the

basis of the documentation. The conclusions drawn are:

a. There is diversity and variation in the genetic composition of a population and this provides

the rough shape that natural selection works on.

b. Organisms vary (could be due to mutations or other mechanism of genetic variability) and

this variation is then inherited.

c. Natural over productive tendencies, but natural tendency to maintain a constant population

Reference

Pinel, John P.J. (2003) Biopsychology (5th edition) Allyn and Bacon Singapore

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