1. LOCOMOTION II: SEGMENTATION AND BEYOND

2. The next step - worms

3. Annelida - a significant improvement in body architecture SEGMENTATION Dividing the body into smaller repeated units

4. Annelida - a significant improvement in body architecture SEGMENTATION - Why?? 1. Allows more precise movement - reorient and twist part of the body

5. Annelida - a significant improvement in body architecture SEGMENTATION - Why?? 2. Allows muscle contraction without bulging Standard coelomate body plan. mesoderm = muscle If muscle contracts without segments contracting area

6. Annelida - a significant improvement in body architecture SEGMENTATION - Why?? 2. Allows muscle contraction without bulging If muscle contracts without segments If muscle contracts with segments Area of contraction is restricted

7. Annelida - a significant improvement in body architecture SEGMENTATION - Why?? 2. Allows muscle contraction without bulging

8. Longitudinal muscles contract Circular muscles relax Longitudinal muscles relax Circular muscles contract

10. Earthworm movement Centre of contraction Affected segments

11. Polychaete worms Add a new feature – appendages

12. Polychaete worms Parapodia

13. Nereis Two kinds of locomotion 1) Slow crawl Recovery stroke Propulsive stroke Contraction of levator muscles Contraction of transverse parapodial muscles

14. Nereis Two kinds of locomotion 1) Slow crawl 2) Fast crawl

15. ARTHROPODS: HARD AND CRUNCHY

16. Insect Integument (Exoskeleton) NH O = C - CH 2 CH 2 OH O NH O = C - CH 2 O N - acetylglucosamine polymer O HH H OH H H O CH 2 OH H H OH H n

17. Insect Integument (Exoskeleton) CO NHCO NHCO NHCO NHCO NHCO NH CO NHCO NH CO NHCO NHCO NHCO NH hydrogen bonds NH O = C - CH 2 CH 2 OH O NH O = C - CH 2 O HH H OH H H O CH 2 OH H H OH H

18. Insect Integument (Exoskeleton) N - acetylglucosamine polymer microfibril sheets of microfibrils orientation of microfibrils changes

19. Insect Integument (Exoskeleton) Protein Matrix

20. Insect Integument (Exoskeleton) Cross linking of protein matrix

21. Insect Integument (Exoskeleton) OH Cross linking of protein matrix OH C CH 2 Protein OH CH 2 O O OH CH 2 Protein N-acetyl dopamineN-acetyl dopamine quinone

22. What other common material has cross-linked fibres in a matrix? Plywood Oriented Strand Board (OSB) Plywood

23. Insect Integument (Exoskeleton) Tensile strength of sclerotized chitin (sclerotin) kg/mm 2

24. Insect Leg - Articulation monocondylic Decreasing mobility Increasing strength dicondylic leg

25. Insect Leg Muscles Extensor Flexor Dicondylic joint

26. Scorpion leg musculature

27. Echinodermata – tube feet – back to hydrostatics Motion of tube feet - video

28. Echinoderm structure

30. Tube Foot Structure

31. Ampullar muscle Postural muscle Longitudina l retractor Radial canal muscle ValveResultant action 1ContractsRelaxCloseExtend tube foot 2Relax ContractCloseShorten tube foot 3Contract RelaxCloseMove foot to the side 4Contract RelaxCloseMove foot to the side 5ContractRelaxClose 6ContractOpenExtra extension of tube foot 1. 2. 3. 4. 5.

32. 6. valve