locomotion in different phylum of non chordate

1. Locomotary organ & locomotion in Non chordate
Dr. Sonia Bajaj
Assistant Professor
Department of Zoology
Shri Shankaracharya Mahavidyalaya ,Junwani ,Bhilai

2. Introduction
• Different organism needs different things for their survival and reproduction.
• To obtain food and defence itself from predator they must move.
• Their are different mechanism for movement one of them is hydrostatic movement. Hydrostatic movement occur when
dominantly muscles are involved in their movement many organism show such kind of movement including Hydra, Earthworm,
Leeches and Echinoderms.
• In some of the animal muscle are well develop for example as in the case of annelids while in the case of hydra due to less
development of gastrointestinal and other muscle fibres hydrostatic movement is performed with the help of epidermal muscle
fibres. Brown and white hydra can remain fixed at one spot for considerable time but green hydra can move often from place to
place by several ingenious devices. They twist about or perform movement to change their location either in response to light or
some chemical stimulus or to obtain food.
• In echinoderm most peculiar and interesting role of water vascular system is to bringing about locomotion by providing hydraulic
pressure mechanism.
Definition (Locomotion)
Progression of an organism through the medium in which organism changes its place and position.
(or)
Movement of an organism from one place to another in search of food or shelter or partner or to escape from its predator.

3. locomotion in Protozoa
Protozoa are the unicellular, free-living or parasitic, eukaryotes belong to
the kingdom Protista.
The locomotory organs of protozoa are cilia, flagella and pseudopodia.
Rate of movement: 0.2μM to 3.0µM per second; Formation of pseudopodia
by the streaming flow of cytoplasm occurs in the direction of movement.
1. Pseudopodia : Pseudopodia are also called the false-feet.
These are the cytoplasm-filled parts of the cell and formed temporarily by
which organisms are able to change their form in order to move. For e.g.
Amoeba
2. Flagella: Flagella are long, slender, thread-like cell organelle present on
the surface of a cell Their structure resembles that of cilia. E.g. Euglena,
Trypanosoma.
3. Cilla: Cilia are the hair-like short cell organelle extending from the cell
surface. Cilia bearing protozoan is Paramecium.
4. Pellicular contractile structures: In many protozoa there is contractile
structures present in pellicle or ectoplasm, called myonemes, which are in
the form of ridges or grooves (E.g. Euglena) or contractile myofibrils or
microtubule (e.g. Trypanosoma).

4. Pseudopodia /(cellular extension) locomotion
• Pseudopodia temporary outgrowths of protoplasm.
• Considered to be the most primitive type.
• Characteristic of the super class - Sarcodina, some Mastigophores and Sporozoans
• Pseudopodia are formed from any part of the body.
• The process of formation of pseudopodia was explained by 'Sol-gel Theory' or
'Change of Viscosity Theory', proposed by Hyman, supported by Mast and Pantin
• Involves slow creeping on substratum
• Speed ranges from 2 to 3 microns/second
• Based on size, shape, structure and mode of working pseudopodia are 4 types
Depending on the structure of the pseudopodia:
1. Lobopodia: These are lobe like and blunt structures with broad and rounded ends.
These structures composed of endoplasm and ectoplasm. Lobopodia move by pressure
flow mechanism.
Eg: Amoeba proteus, Entamoeba histolytica
2. Filopodia: These are slender filamentous pseudopodia tapering from base to tip.
Sometimes these may be branched out but they are not fused to form a network. They are
composed of only ectoplasm.
Eg: Euglypha, Lecithium

5. 3. Reticulopodia: They are also known as rhizopodia or myxopodia. They are
filamentous, profusely interconnected and branched. They form a network. The
primary function of these pseudopodia in ingestion of food and the secondary
function is locomotion.
Eg: Elphidium, Globigerina
4. Axopodia: These are fine needle like, straight pseudopodia radiating from the
surface of the body. Each Axopodia contain a central axial rod which is covered by
granular and adhesive cytoplasm. The main function of these axopodia is food
collection. Axopodia also exhibit two-way flow of cytoplasm. Axopodia are mainly
found in Heliozoans and radiolarians.
Eg: Actinosphaerium, Actinophrys, Collozoum
Flagella locomotion
• Flagella are the locomotory organelles of flagellate mastigophoran protozoans.
• They are mostly thread like projection on the cell surface.
• Speed ranges from 15 to 300 microns/second
• The axoneme arises from basal granule called as blepharoplast or kinetosome
which is further derived from Centrioles.
3 types: 1. Paddle stroke: Side ways lashing of flagella. It consists of a down stroke,
and a recovery stroke. Thus animal moves forward, gyrates and rotates on its
longitudinal axis-
2. Undulating motion: Animal moves forward when wave-like undulations proceed
from tip to base of the flagellum. It moves backward when undulations pass from base
to tip. Animal rotates in opposite direction when undulations are spiral (works on the
principle of airplane propeller)
3. Simple conical gyration: Spiral turning of the flagellum like a screw pulls the animal
forward.

6. • When the axial filament is viewed under an electron microscope 9 + 2 arrangement can be observed. The 2 central
longitudinal fibers are enclosed by membranous inner sheath. The 2 central longitudinal fibers are surrounded by 9
longitudinal peripheral doublets (each with microtubules A and B) which form a cylinder between the inner and the outer
sheath.
Types of Flagella
1. Stichonematic: Only one row of lateral appendages occurs on the axoneme up to tip. Eg: Euglena, Astasia
2. Pantonematic: Two or more rows of lateral appendages occur on the axoneme.Eg: Peranema, Monas
3. Acronematic: Lateral appendages are absent and axoneme ends as a terminal ‘naked’ axial filament.Eg: Chlamydomonas,
4. Pantacronematic: Flagellum is provided with two or more rows of lateral appendages and the axoneme ends in a terminal
naked axial filament.Eg: Urceolus
5. Anematic: In some cases the flagella is simple without any lateral appendages and a terminal naked ilament.Eg: Chilomonas,
Cryptomonas

7. locomotion in Porifera
• Sponges are generally sessile as adults and spend
their lives attached to a fixed substratum.
• They do not show movement over large distances
like other free-swimming marine invertebrates.
• Sponge cells are capable of creeping along substrata
via organizational plasticity, i.e., rearranging their
cells.
• Rate of movement: sponges can crawl up to 160
microns/hr (4 mm/day).
• sponge cells spread on a physical support
demonstrate a leading edge for directed movement.
• It has been speculated that this localized creeping
movement may help sponges adjust to
microenvironments near the point of attachment.

8. locomotion in coelenterate
• Locomotion takes place by smooth muscle fibers and tentacles. Some like coral and
sea anemone remain fixed on substratum.
• Deposition of calcium carbonate by coelenterates are called corals.
Hydra- remains attached by the basal disc to some suitable object in the water. There it
twists about and makes various movements of the tentacles and body in response to
various stimuli and for the capture of food. All such movements are caused by the
contraction or expansion of the contractile muscle fibres of the muscle processes of
both epidermis and gastro dermis.
1. Dragging : The tentacles are stretched and adhere to some object . The foot is
released and body is pulled to the object by contraction of the tentacles .
2. Looping : the body is extended and bent over to fix the tentacles over the
substratum . The foot is now released, drawn closer to the oral end and fixed again .
The tentacles are then freed and the body resumes an upright position.
3. Somersaulting : Sometimes the foot is put down beyond the tentacles so that the
animal appears to somersault .
4. Walking : In walking Hydra moves in an upside down position using its tentacles as
legs .
5. Floating : Hydra may secrete a gas bubble which detaches it from the substratum
and brings it to the surface . Here the bubble breaks and spreads out like a raft . From
raft Hydra hangs and floats in water .
6. Gliding : The cells of the foot form pseudopodia Hydra moves on the substratum
with the help of pseudopodia . This process is called gliding .
7. Climbing : Hydra can climb after getting attached to a twig or leaves with the help of
tentacles . The attached tentacles contract . Then the rest of the body contracts .

9. Locomotion in Platyhelminthes
• The class Turbellaria or planaria includes mainly free-living, marine species, although
some species live in freshwater or moist terrestrial environments. They move by
the action of cilia and by muscular undulation. They generally locomote by
coordinated waves of cilia on a secreted mucus trail. Some species also swim by rhythmic
muscles contractions. The ventral epidermis of turbellarians is ciliated which facilitates their
locomotion. The cilia, muscles and mucus secreted helps in locomotion.
• The beating of cilia creates turbulence in the water so named as turbellaria.
• They spread a sheet of mucus during their movement. This mucous help in
adhesion and helps the cilia gain traction. They glide over the substrate.
• The class cestodes or tapeworms- are also internal parasites mainly of vertebrates.
Tapeworms live in the intestinal tract of the primary host
• They have sucker and scolex for attachment to host body
• Suckers-A sucker in to specialized attachment organ of an animal. It acts as an adhesion
device in parasitic worms. The parasitic flatworm have adhesive organs in the form
of two suckers. The anterior sucker is the oral sucker that surrounds the mouth and the
other sucker called as Acetabulum is located ventrally on the middle portion of the body.
They are basically structures to stay in host or hang on to their host.
• Hooks -They are also use as attachment organs by flatworm parasites.
• Scolex-Scolex Some members of flatworms have scolex. It is an hold fast structure having
circular suckers and a rostellum of hooks. With the help of scolex the worm attaches itself to
intestinal wall of host.

10. Locomotion in Annelida
The basic features of locomotion in annelids are most easily observed in the earthworm
because it lacks appendages and parapodia.
• Movement involves contracting body muscles of body wall and setae.
• most have setae (chitonous bristles secreted by the epidermis) that aid in locomotion and
burrowing.
• A wave contraction affecting its circular muscles, begins at the anterior end and travels
posterior. This causes the body to become thinner and longer. This will allow the body to
move forward.
• There will be another wave of contraction followed by previous wave but this time it will
effect longitudinal muscles causing thickening and shortening of body. Here there will be
no movement as they become anchor to the ground by protruded setae.
• This again followed by wave of thinning and the process is repeated alternately.
• It has been calculated that by this method earthworm travels about 25cm in 1 minute.
• When direction of wave reversed the worm crawls back.
• During locomotion Skeletal System fluid in coelom acts as a hydrostatic skeleton . When
contraction of circular muscle takes place body becomes stiff and aid the relaxation of
longitudinal muscles.
• (Hydrostatic Movement)- When one set of muscles in annelids contracts in a circular and
longitudinal pattern, the other set of muscles stretches in response.

11. Looping or crawling movement
• These is perform with the help of muscles and sucker which serves for its
attachment.
• Leech fix its posterior sucker firmly on substratum and secretes the slimy
secretion from the sucker gland.
• This allow the contraction of circular muscles and relaxation of longitudinal
muscles hence the anterior part of body is extended as far as possible.
• When leech fixes the anterior sucker it leads to relaxation of circular muscles
and contraction of longitudinal muscles takes place which allow release of
posterior sucker and allow to shorten the body.
• When posterior end is moved forward closer to anterior sucker loop
formation will take place.
• Again same process will be repeated. This type of motion is refer to as leech
like locomotion.
Swimming- It swims very actively in water. Body becomes dorsoventrally
flattened during swimming and performs successive undulating movements.

12. Locomotion in Arthropod
• Arthropods possess jointed appendages for locomotion; some arthropods such as
insects, also possess wings in addition to the jointed appendages.
• Locomotion of Prawn: The prawn moves in three different ways—crawling, swimming
and darting. At the time of crawling the animal straightens its body and rests over five
pairs of walking legs.
• Prawn performs crawling movements with the help of its walking legs in its natural
habitats such as bottom of rivers, ponds etc. While swimming it uses its pleopods whose
endo and exopodites act as oar.
• When in danger or disturbed, it takes a quick back spring by rapid pulling of uropods and
telson ventrally with a powerful stroke.
• Appendages/limbs move sequentially in one direction - pushes water in one direction.
• Organism can move forward.
• Using appendages to allow water to go thru.
• Recovery & power stroke for swimming
• Power stroke = has contact with surface. Muscles are tense.
• Recovery stroke = lifted, working flexors
• Highly modified for swimming or crawling
• Tail segment
• Appendages move laterally and up and down - allows them to walk

13. Locomotion in Mollusca
• The locomotory organ in snail is the 'muscular foot‘.
• Pila performs slow creeping movement.
• At the time of locomotion, the pedal gland cells secrete slime due to which
a slimy path is formed which is sticky and smooth at first but later on dries
and stiffens.
• The animal moves on this path by undulating movements resulting from
the contraction and relaxation of pedal muscles.
• The extension of foot for locomotion is brought about by the combined
effect of the activity of its muscles and the blood pressure in blood sinuses
of the foot.
• The contraction of the foot occurs as a result of muscle action and
decrease in the blood pressure in the blood sinuses.
• locomotion in Pila occurs as a result of successive extension and
contraction of foot.

14. Locomotion in Echinodermata
• The Sea star passing through the ring canal, radial canals and lateral canals fills up
in the ampullae of tube feet.
• To start the locomotion, the ampullae contract and the valves in the lateral canals
close so that the water flows from ampullae into the podia as a result they
become long and rigid and extend forward and adhere to the substratum by the
sucking action of the suckers.
• The suckers rise above from the centre creating vacuum and simultaneously due to
the mucus secreted from the edges, the adhesion becomes more rigid. Now the
body is pulled forwards by muscular action.
• Now the podia which are lined with longitudinal muscles only contract their
muscles and reduce their length so that water goes back into the ampullae and
thus anchorage to the substratum loosens.
• Now again the arm is extended forward in the direction of locomotion and the
whole process is repeated.
• All the tube feet are not capable of working together. If needed, sea star can also
climb upon rocks.
• The body of the sea star capsizes, the tips of one or two arms twist to bring their
tube feet in contact with the substratum and after that the whole body is
overturned to resume the original position.

15. References
• A textbook of chordate-H.S. Bhamrah & kavita Juneja
• Invertebrate Zoology-P.S. Dhami & J.k. Dhami
• Modern text book of Invertebrate-R Kotpal
• Invertebrate Zoology 14 edition-Jordan & Verma