The document discusses ethology, the study of animal behavior in natural environments, focusing on the development of behavior throughout different life stages of animals. It highlights the impact of genetic and environmental factors on behavioral development, emphasizing the significance of critical periods for learning and adaptation. Various concepts like ontogeny, maturation, and innate behaviors are explored to illustrate how behavior is influenced by both nature and nurture.

1. ETHOLOGY
Prof. S. D. Rathod
B N Bandodkar College of Science
Thane, Maharashtra, India

2. Ethology: Definition
 Study of animal behavior in their natural
environment.
 Ethology is biological study of animal
behavior.

3. Development of Animal
Behavior
 Animals exhibit different behavior at their
different ages more or less in orderly
sequence.
 When and how the animals start exhibiting
different kinds of behavior in their life time?
 Therefore study of onset (development) of
behavior is of utmost concern.
 Firstly we consider ontogency i.e. study of
development of learning and memory in
embryonic condition.

4. Ontogency: Ontogeny of
Behavior
 Ontogency is studied at embryonic
stage of animals.
 Study is divided in to three stages viz.
 1) Neonatal roots of behavior;
 2) Maturation and behavioral changes
and
 3) Phenomenon of equifinality

5. Neonatal roots of behavior
 Behavior can be
observed at
embryonic stages
such as twitching
and jerking
movements of
appendages.
 Flexes the hind leg
 Pecks beak inside
egg

6. Types of embryos
 Precocial: when newly born resemble adult
and can feed, move and defend themselves
e.g. Lamb of sheep.
 Altricial: when are helpless without parent
can’t survive e.g. Joey of kangaroo.
 Precocial Altricial

7. Concepts of Behavioral
development
 1. Preformation
 2. Epigenesis: Proposed by Needleem in
1959; many supported it, Davis, Kutsch,
Hamburger
Brown (1975) explained epigenesis
P1+G1+E1 = P2
P2+G2+E2 = P3
P3+G3+E3 = P4

8.  3. Reflexogenous concept: Neuromuscular
pathways are predetermined but movements
are not exhibited until pathways develop.
 4. Systemogenous behavior: Movements or
behavior develop before birth and pattern of
behavior depends up on the environmental
factors available at that time. The behavior
also vary from species to species.
 Probabilistic viewpoint: a/c this the early
behavioral development is not
predetermined rather it is probabilistic
dependent on the stimulating factors.

9. Maturation and behavioral
changes
 Frog jumps to blue background
 Tadpole jumps to green background


11.  As animal grows, it Practices for survival:
involves increasing completion, organization
or reinforcement of neural pathways
 Practice also improves behavior

12. Phenomenon of equifinality
 It is a phenomenon by which a structure or
behavior pattern may develop by different
pathways. There are vast number of process
to finalize the personality of a fully mature
grown up adult.

13. Conclusions:
 Simple "nature/nurture" or "instinctive/learned"
dichotomies have now been abandoned
 Nowadays ethologists and psychologists are less
divided by the nature - nurture debate. Both
groups are interested in how genetic and
environmental factors interact to control the
development and expression of behaviour.
 All behaviour depends on both genes and
environment

14. Impact of environment on
behaviour

15. Effect of Environment
 Enriched environment enhance the problem
solving ability in rats whereas the deprived
environment has been found to affect the
performance of them at later stage.
 Enriched environment during development led to
heavier and thicker brain cortex tissue, larger
neurons and more dendrites of rat and also the
increase in acetylcholine esterase activity as
compared to rats living in deprived environment.
 Environmental impact on behavior occur during
sensitive period or critical period only.

16. Sensitive Period In Cats
David Hubel and Torsten Wiesel’s experiments
Kitten is deprived of normal visual experience during a critical period
One eyelid was sutured shut. When it
reached adulthood (around 6 months),
its eyelid was opened again. Showed
an abnormally low number of neurons
and loss of binocular vision as compared
to other eye. Visual deprivation took place
during the first three months of the cat’s
life.
Eye of an adult cat was sutured for a year had no effect on its visual
ability.

17. Sensitive Period In Primates
Phenomenon also occurs
in primates,
Critical period is longer
(up to age 6 months).
Austin Riesen reared
monkeys in darkness for
the first 3 to 6 months of
their lives. When these
animals were then
introduced into a normal
environment, they had
great difficulties in
distinguishing even the
simplest shapes.

18. Sensitive Period During
Development
 Various behaviors are acquired by individuals during
sensitive or critical period of their life e.g. imprinting or
song in singing birds.
 Filial imprinting: young animals form an impression of
their parent soon after hatching or birth and follows
them. If any object is produced during birth as the
young one accepts it as parent and follows it.

19. Chick follows even the
object which is
available at hatching
and understands it as
parent.

20. This diagram shows the similarities in the sonograms
of two geographically dispersed subspecies of white
crowned sparrow: (Zonotrichia leucophyrs)
 Californian Sierra
Nevada mountains
 The central Californian
coast
 Swamp sparrow
(Melospiza georgiana)
different species

21. Development of white crowned sparrow song
under normal conditions
 From 10 to 50 days of age, the young male's template
accepts this adult male white crowned sparrow song as a
model:
 and rejects this swamp swallow song as a model:

22.  The improved template now specifies the dialect he has to
learn. The young bird does not sing, but the model is
remembered for two months or more
 The maturing male begins singing its sub song at about 150
days of age. During this period vocal output is gradually
matched to the dialect specified by the improved template

23. Primary song –white crowned
sparrow
 At about 200
days of age
full song
begins, it is a
copy of the
model he
learned in his
youth:

24. Juvenile Behaviour

25. Juvenile Behaviour
 Frog jumps to blue background
 Tadpole jumps to green background

26. Juvenile behaviuor
Juvenile behave
different than
the adults…….
While Goose is
ready to fight
enemy,
goslings hide
in the grass

27. Innate Behaviour

28. Innate Behaviour
 Behavior may occur as a result ofan external
stimulus (e.g., sight of a predator)
 internal stimulus (e.g., hunger)
 Stereotypic in response to a stimulus
 or, more often, a mixture of the two (e.g.,
mating behavior)
Stimulus IRM FAP
e.g.:- three spined stickleback fish

29. Innate Behaviour

30. THANK YOU