LOCOMOTION II: SEGMENTATION AND BEYOND. The next step - worms.
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Transcript of 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??
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
Standard coelomate body plan.
mesoderm = muscle
If muscle contracts without segments
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 contractCircular muscles relax
Longitudinal muscles relaxCircular muscles contract
Nereis
Two kinds of locomotion
1) Slow crawl
Recovery stroke
Propulsive stroke
Contraction of levator muscles
Contraction of transverse parapodial
muscles
Insect Integument (Exoskeleton)
NH
O = C - CH2
CH2OH
O
NH
O = C - CH2
O
N - acetylglucosamine polymer
OH H
H
OH
H
H
O
CH2OH
H
H
OH H
n
Insect Integument (Exoskeleton)
CO
NH CO
NH CO
NH CO
NH CO
NH CO
NH
CO
NH CO
NH
CO
NH CO
NH CO
NH CO
NH
hydrogen bonds
NH
O = C - CH2
CH2OH
O
NH
O = C - CH2
OH H
H
OH
H
H
O
CH2OH
H
H
OH H
Insect Integument (Exoskeleton)
N - acetylglucosamine polymer
microfibril
sheets of microfibrils
orientation of microfibrils changes
Insect Integument (Exoskeleton)
OH
Cross linking of protein matrix
OH
C
CH2
Protein Protein
OH
OH
CH2
CH2
O
O
CH2
CH2
OH
OH
CH2
CH2
Protein Protein
N-acetyl dopamine N-acetyl dopamine quinone
What other common material has cross-linked fibres in a matrix?
Plywood Oriented Strand Board (OSB)Plywood
Echinodermata – tube feet – back to hydrostatics
Motion of tube feet - video
Ampullar muscle
Postural muscle
Longitudinal retractor
Radial canal
muscle
Valve Resultant action
1 Contracts Relax Close Extend tube foot
2 Relax Relax Contract Close Shorten tube foot
3 Contract Contract Relax Close Move foot to the side
4 Contract Contract Relax Close Move foot to the side
5 Contract Relax Close
6 Contract Open Extra extension of tube foot
1.
2.
3.4.
5.