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LOCOMOTION II: SEGMENTATION AND BEYOND. The next step - worms. Annelida - a significant improvement in body architecture. SEGMENTATION. Dividing the body into smaller repeated units. Annelida - a significant improvement in body architecture. SEGMENTATION - Why??.
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Annelida - a significant improvement in body architecture SEGMENTATION Dividing the body into smaller repeated units
Annelida - a significant improvement in body architecture SEGMENTATION - Why?? 1. Allows more precise movement - reorient and twist part of the body
Annelida - a significant improvement in body architecture SEGMENTATION - Why?? 2. Allows muscle contraction without bulging mesoderm = muscle If muscle contracts without segments Standard coelomate body plan. contracting area
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
Annelida - a significant improvement in body architecture SEGMENTATION - Why?? 2. Allows muscle contraction without bulging
Longitudinal muscles relax Circular muscles contract Longitudinal muscles contract Circular muscles relax
Earthworm movement Centre of contraction Affected segments
Polychaete worms Add a new feature – appendages
Polychaete worms Parapodia
Nereis Two kinds of locomotion 1) Slow crawl Contraction of levator muscles Recovery stroke Contraction of transverse parapodial muscles Propulsive stroke
Nereis Two kinds of locomotion 1) Slow crawl 2) Fast crawl
Insect Integument (Exoskeleton) N - acetylglucosamine polymer O = C - CH2 NH H CH2OH O O H H H H OH O H H OH O NH CH2OH H O = C - CH2 n
Insect Integument (Exoskeleton) O = C - CH2 NH H CH2OH O H H H H OH O H H OH O NH CH2OH H O = C - CH2 CO NH CO NH CO NH NH CO NH CO NH CO CO NH CO NH CO NH NH CO NH CO NH CO hydrogen bonds
Insect Integument (Exoskeleton) microfibril N - acetylglucosamine polymer sheets of microfibrils orientation of microfibrils changes
Insect Integument (Exoskeleton) Protein Matrix
Insect Integument (Exoskeleton) Cross linking of protein matrix
Insect Integument (Exoskeleton) Cross linking of protein matrix OH O OH OH O OH OH OH Protein Protein CH2 CH2 CH2 Protein Protein C CH2 CH2 CH2 CH2 N-acetyl dopamine N-acetyl dopamine quinone
What other common material has cross-linked fibres in a matrix? Oriented Strand Board (OSB) Plywood Plywood
Insect Integument (Exoskeleton) kg/mm2 Tensile strength of sclerotized chitin (sclerotin)
Insect Leg - Articulation monocondylic dicondylic leg leg Decreasing mobility Increasing strength
Insect Leg Muscles Extensor Flexor Dicondylic joint
1. 2. 5. 4. 3.
6. valve