Various Locomotion methods in Protista.pptx

Various Locomotion methods in Protista

1. Locomotion in Protista

2. The movement of an organism from one place to another is known as locomotion.  Locomotion is an important feature of the living organism. The protists are unicellular and eukaryotic organisms. They are motile organisms and locomotion helps them in survival through sensing their environment, feeding, reproduction and other features. Protists are single celled organisms that move through either by locomotory organelles or by secretions. The locomotory organelles is an important characteristic of the protists . 

3. In Protists , the important mechanism of locomotion is through the use of different structures such as pseudopodia, flagella, cilia, wriggling and locomotion through mucilage propulsion. Pseudopodia are characteristics of Sarcodina , Flagella are characteristics of Flagellata ( Mastigophora ), Cilia are characteristics of Ciliata and myonemes are characteristics of Sporozoa .

4. Five modes of locomotion are recognized in the protista . They are: Pseudopodial locomotion, Flagellar locomotion, Ciliary locomotion, Wriggling locomotion Locomotion by mucilage propulsion

5. A. Locomotor organelles Include pseudopodi a, flagell a , cilia and pellicular contractile structures

6. 1. Pseudopodia False feet Temporary structures formed by streaming flow of cytoplasm Formed from ectoplasm but also have a core of endoplasm

7. 1. Pseudopodia Movement occurs when the cytoplasm slides and forms a pseudopodium in front to pull the cell forward. This type of movement has been linked to changes in action potential, though the exact mechanism is still unknown Sarcodina

8. On the basis of for m & structure pseudopodia are 4-types : Lobopodia Filopodia Reiticulopodia Axopodia

9. a. Lobopodia Lobe-like pse u dopodia Hav e broa d & rounded ends Compo s e d of b oth ecto & endoplasm Move b y press u re flow mechanism Amoeba

10. b. Filopodia More or less fila m entou s pseudo p odia Tapering fro m bas e to pointed tip Composed of ecto p lasm only May branc h forming simple or complex networks Euglypha

11. c. Reticulopodia Rhizo or myxopodia Filamentous Branched & interconnected profusely t o for m a network Display 2-wa y flow of cytoplasm (moves in both clockwise and anticlockwise directions) Formed from ectoplasm. Foraminiferans , Globigerina

12. d. Axopodia More or less straight Ra d ia t e fro m surface of body Cont a i n a cen t ra l axi a l rod covered by granular & adhesive cytoplasm Als o displa y 2 - wa y flo w of cytoplasm Heliozoans Actinosphaeriu m & Actinophrys

13. 2. Flagella Locomotor organelles of flagellates Euglena , Trypanosoma Thread-like projec t ion s on cell surface Consists of an elongate , stiff axi a l filament ( axoneme ) enclose d b y an outer sheath

14. In axoneme, 9- longitudinal peripheral paired fibers form a c y linder surrounding 2-central longitudinal fibers enclosed by a membranous inner sheath Each peripheral pa i r bear s a double row of short arms

15. Axoneme arises from a basal granule ( blep h aroplast or kinetosome ) A cylindrical body forme d b y base s of peripheral fibers Blepharo p lasts are derived from centrioles as both are homologous

16. Fibers of axoneme remai n embedd e d in a fluid matrix In between outer ring of peripheral fiber s & inne r ring of central fibers occur 9-accessory fibers In Mastigophora , masti g onemes arise from outer sheath

17. Number & arrangement of flagella vary in Mastiog p hora from 1-8 or more Free living spe c ies usually have 1 or 2 In parasitic species number may range to many

18. 3. Cilila Ch a ra c teristi c of Ciliata Res e m b le fl a gella in basic structure Highl y vibr a tile , small ectoplasmic processes Electron microscope rev e als pres e nc e o f a n external membranous she a t h continuous w ith plasma membrane enclosing fluid matrix

19. Running along entire length of cilium are 9- paired peripheral fiber s & 2 -central fibers , all embedded in a structureless matrix Central fiber s are enclosed within a delicate sheath

20. In between outer & inne r fibe r ring s lie 9 - spoke-like radial lamellae 1-subfiber or microfiber of each peripheral pair bears a double row of short projections ( arms ) Al l poi n tin g i n same direction Ea c h c i lium aris e s from a basal granule ( bleph a roplast )

21. Lenhssek & Henneguy (1898 ) : ba s al gr a nule s a re derivatives of centrioles Basal granules show 9- periph e r a l subfib e r triplets each disposed in a twist- like fashion I n m a n y species cilia f u se forming compound organelles Undulating membranes ( Trypanosoma ), m e m b r a nell e ( V o rtice l l a ) & cirri ( Euplotes )

22. Differences in Cilia and Flagella: Cilia are similar to flagella in structure and function but differ in following ways: They are short in length than flagella. They are larger in number. Cilia possess no mastigonemes as found in flagella. No connection of basal granule with nucleus in cilia. In flagella the rhizoplast join the basal granules to the nucleus.

23. 4. Pellicular Contractile Structures Many have c ontractile structures in pellicle or ectoplasm ( myonemes ) May be in the form of ridges & grooves ( Euglena ) or contra c til e myofibrils ( larger ciliates ) or microtubules ( Trypanosoma )

24. B. Methods of Locomotion Basi c ally 5 - known methods Pseudopodial / Amoeboid Flagellar Ciliary Wriggling Mucilage propulsion Speed in amoeboid form s 0. 2µ - 3µ/ s ec I n f l ag e llates 15µ- 300µ 400 µ - 2, 00 µ i n cili a tes

25. 2. Amoeboid movement Ch a rac t eristi c of Sarcodina , some Mastigophora & Sporozoa Formation of pseudopodia by streaming flow of c y toplas m i n dire c tion of movement Locomotion possible only over surface

26. Exa c t me c h a nism involved in pseudopodia not known Sol-Gel theory by Mast & Pant i n (19 2 5) accepted Formation of pseudopodia depends upon contraction of ectoplasmic tube ( Plasmagel ) at post e rio r en d of body

27. Resultin g i n forward flow of endoplasm ( Plasmasol ) into pseudopodia Process involves cont i nuou s solation at posterior end & gelation at anterior end Theory further developed by Goldacre & Lorch (1 9 50 ) & Al l an & Rosalasnsky (1958)

28. 2. Flagellar movement Characteristic of Masti g op h ora having 1 or more flagella Need liquid medium for movement 3-types of movements recognized

29. a. Paddle stroke Obs e rve d b y Ulehla & Krijsman (1925) Movement of fla g ellu m i s si d eways lash Consists of an effective down stroke with flagellu m held out rigidly

30. A relaxed recovery stroke where flagellu m i s s trongly curved, brought forward again A s a re s ul t a nimal moves forward , gyrates Also caused to rotate on its longitudinal axis

31. b. Undulating motion Wav e -like undulat i ons in flagellum when proceed from tip to base Pulls animal forward Backward movement ca u sed whe n undulations pass from base to tip When spiral cause animal to rotate in opposite direction

32. c. Simple conical gyration Butschill’s screw theory postulates a spiral turning of flagellum like a screw Exerts propelling action, pulling animal forward through water with a spiral rotat i on as wel l as gyration ( revolving in circles ) around axis of movement

33. According to Lowndes , a series of spiral waves pass successively from the base to the tip of the backwardly directed flagellum at about 12 per second with increasing velocity and amplitude The waves proceed along the flagellum in a spiral manner and cause the body of Euglena to rotate once in a second. Thus, in its locomotion, it traces a spiral path about a straight line and moves forward. The rate of movement is 3 mm per minute.

34. Mechanism producing flagella r bea t unknown Believed that some axon e mal fiber s involved Slidin g tubul e t h eor y is latest Adjacent doublets slide past each other causing entire flagellum to bend Cross bridge s forme d & energy utilized for process is supplied by ATP

35. 3. Ciliary movement Most cilia t e s move in spiral path Rota t e on the i r axis as they move Spiral movement is due to in opposite direction on 2-sides of pseudopodial filaments oblique strokes of all body cilia work together & strike i n same dire c tion

36. Coordination of ciliary movement is due to linkage of basal bodies by kinetodesmata Liquid medium needed Large cilates are swif t es t swimmers, Paramecium caudatum is champion

37. Resembles the swing of pendulum except tha t i t i s more ra p id in some direction Backward & forward vibrations produce a paddle stroke effect Backwar d e ffec t ive stroke more active during which movement brought about

38. Forward recovery stroke produces no signifi c ant mo v ement While moving succession of beats coordinated in well known pattern of metachronal rhythm comp a re d t o passa g e of wind over wheat field Ciliary movement is base d on contra c tio n of peripheral fibers

39. 4. Wriggling Locomotion: It is slow worm-like movement which is performed with the help of a wave of contraction and expansion in the body. Eg : Sporozoans , Non-flagellates, Euglenoids .

40. Myonemes : The myonemes are extremely fine and highly contractile structures running in various directions in the pellicle or ectoplasm of various Protozoa. They serve chiefly to alter the shape of the body. Some Protozoa, like Amoeba, which do not possess myonemes , can also change their shape, but this is due to the general contractility of the protoplasm. The myonemes may be in the form of ridges and grooves (e.g. Euglena), or microtubules (e.g. Trypanosoma ), or myofibrils (e.g. Ciliates). The myonemes find their greatest development in Ciliata . They are band-like and cross-striated in Stentor . In certain stalked ciliates ( Vorticella ) the longitudinal myonemes of the body proper converge, basally into the stalks forming the spasmoneme .

41. In some ciliates ( Stentor ) and larger gregarines ( Monocystis agilis ), the myonemes lie inside individual hyaline ectoplasmic canals. In many Gregarinida , they are arranged longitudinally, transversely and spirally and apparently used in locomotion. In certain Radiolaria ( Acanthometron ) 10-30 short, thick myonemes ( myophrisks ) are connected basally to each radiating spicule . These serve as hydrostatic organelles since their contractions and expansions cause variations in the volume of the body, which is thus enabled to rise or sink in the water

42. Euglenoid Movement or Metaboly : Euglena sometimes shows a very peculiar slow wriggling movements. A peristaltic wave of contraction and expansion passes over the entire body from the anterior to the posterior end and the animal moves forward. The body becomes shorter and wider first at the anterior end, then in the middle and later at the posterior end. This type of movement is called euglenoid movement by which slow and limited movement occurs. Euglenoid movements are brought about by the contractions of cytoplasm or by the contractions of myonemes present in the cytoplasm below the pellicle.

43. 5. Locomotion by Mucilage propulsion The movement occurs in the protists that do not have any types of locomotory organelles. They secrete mucilage that helps them to slip over and glide. The animal moves in the direction opposite to the secretion of mucilage. Some protists like diatoms do not have any organelles of locomotion. They can, however, move from one place to another through secretion of mucilage. This type of locomotion occurs in the direction opposite to that of mucilage secretion.

44. Conclusion: The important locomotory organelles in protists are flagella, cilia and pseudopodia. Flagella is a single, slender long structure while cilia are numerous in number. Cilia helped in locomotion by the synchronized beating movements. Pseudopodia are cytoplasmic extensions of the body. In protists , organisms such as diatoms move by mucilage propulsion.