Biological rythm

The presentation explains the types and phenomenon of biological rhythm

1. Biological rhythms
Dr. SurjyaKumar Saikia
Assistant Professor
Visva-Bharati

2. What we will learn………….
•Ethologyand Chronology
•What is Biological rhythm
•Classification of Biorythms

3. Ethology
•The scientific study of how animals behave,
particularly in their natural environment
•The founders of Ethology,Karl von
Frisch,Konrad Lorenz, andNikolaasTinbergen,
won the Nobel prize for their work in 1973.

4. Chronobiology
Chronobiology is a field of biology that examines
periodic phenomena in living organisms and their
adaptation to solar-and lunar-related rhythms.
From Gkchronos= time, Gkbios= life and
Gklogos= science

5. Biological rhythms –what is it?
•Biological rhythms are the natural
cycle of change in our body’s
chemicals or functions. It’s like an
internal master “clock” that
coordinates the other clocks in your
body.
•The “clock” is located in the brain.
It’s made up of thousands of nerve
cells that help sync your body’s
functions and activities.
•Biological rhythms control much of
the body's normal functions,
including performance, behavior,
sleep and endocrine rhythms etc.

6. Stimulus-Response in a Biological rhythm

7. Parameters of Biological Rhythms

9. 3 major properties
1
•Biological rhythms have self sustaining
pace maker mechanism
2
•They maintain normal cyclicity even in
absence of environmental cues
3
•Biological rhythms are genetically
inherited

10. Categories of BR
•Endogenous:
Within the body
1.Circadian Rhythm
2.Circa-Tidal Rhythm
3.CircannualRhythm
4.Circa-Lunar Rhythm
5.Semilunar Rhythm
Exogenous: An exogenous
type is one that which
involves an external cue
Zeitgeber

11. 1. Circadian Rhythm
•This rhythm is matched
with the 24 hour cycle of
day and night
Ultradianrhythms have a period of less than 24 hours
Infradianrhythmshave a period of more than 24 hours

12. Circadian rhythm disorder
•Delayed Sleep Phase Disorderis a circadian rhythm
disorder most common in adolescents and young adults
whose "night owl" tendencies delay sleep onset --often
until 2 a.m. or later.
•Advanced Sleep Phase Disorderis usually seen in the elderly.
This disorder is identified by regular early evening bedtimes (6
p.m. -9 p.m.) and early morning awakenings (2 a.m. - 5 a.m.).
•Jet Lagresults from a conflict between the pattern of sleep
and wakefulness between the internal biological clock and
that of a new time zone. Individuals find it hard to adjust and
function optimally in the new time zone.

13. 2. CircatidalRhythm
Cycle of high and low tides, roughly twice per
day. Because the tides aren't exactly 12 hours
apart, high and low tide are approximately
50mins later each day.

14. An example of a circatidalrhythm is the vertical migration of the marine
diatomHantzschiathat at high tides descends into the sand, but at low tide
rises to the surface
From research gate

15. Circalunarrhythm
A biorhythm that corresponds with the lunar cycle
(approximately 29.5 days).
The reproductive cycles of many organisms, especially marine
organisms, are linked to changing levels of moonlight and the tidal
cycle, both of which are governed by the phases of the moon.
Platynereisdumerilii

16. The marine midgeCluniomarinuslives in
the rocky intertidal zone of the European
Atlantic coast.
The insect has synchronised its life cycle
with the rhythm of the tides.
Cluniomarinusis a non-bitingmidgeof the
bloodworm family (Chironomidae)
Adults
Low
tide
Cluniomarinus
Circalunarrhythm in Clunio
Neap
Tide
Spring
Tide

17. Semilunarcycle
Itisthebiologicalrhythmswhichare
synchronizedwiththefortnightlycycleof
springtide(hightide)andneaptide(lowtide)
LinkedtotherotationoftheMoonaroundthe
Earthbuthas2cyclesperlunarmonth.
Springtideoccursevery15daysjustafternew
andfullmoon.
Suchrhythmisexhibitedbyperiwinkle
(Littorniarudis).Theyshowamarked15day
periodicityintheirlocomotoryactivity.The
specieslivehighupontheshoreandisonly
coveredbythehighwaterofspringtide.
Periwinkle

18. 3. CircannualRhythm
Endogenously generated biological rhythm with a period length
approximating to 1 year.

19. Amur falcon
Siberia South Africa
(NE India)
Blue throat
North Am. India
(Winter)
The red knot
North Arctic to South America North America to Central and South America
and also towards Africa