BIOL 2003 Lecture Notes - Lecture 11: Myriapoda, Chelicerata, Chemoreceptor
Arthropods
October 14 & 16, 2015
Phylum: Arthropoda
• Over 80% of names animals
• 1.5million+ species
• Invertebrates with segemented bodies
• Has jointed limbs and exoskeleton made of chitin
• Marine, freshwater, terrestrial…and the air!
• Fully adapted to life on land such as amniodes (bird/lizards)
• Human importance:
o Pollination
o Food (ex. Lobster)
o Transmit disease
o Crop infestations
• Key Transitions:
o Tissue – organ system
o Symmetry – bilateral
o Body cavity – coelomate
o Development – triploblastic protostome
o Segmentation – present
• Diversity:
1. Exoskeleton
• Chitinous cuticle; protection and mobility
• Prevent dehydration
2. Segmentation and Appendages
• Specialized functions; more efficient locomotion
3. Respiration increased metabolism
• Can breath air/water; more efficient respiration and faster metabolism
4. Sense Organs
• Ex. Tactile, eyes, hearing, balance, chemosensory
5. Complex Behaviour
• True sociality, ecology, adaptations
6. Metamorphisis
• More environmental niches available to same species therefore, more disperse
• Skeleton/Segments/Appendages:
o Groups of segments + tagmata
o Work together for a common function
o Head, thorax and abdomen
Subphylum: Chelicerata
• Horseshoe crabs, spiders, ticks, scorpions, sea spiders
• 2 tagmata: cepalothorax (head+thorax) and abdomen
• Appendages: chelicerae (pinchers) and pedipalps/ 4 pairs of walking legs
o No mandible jaws, no antennae
Subphylum: Myriapoda
• One pair of antennae
• Mandible jaw
• Centipedes and millipedes
• 2 Tagmata: Head + trunk
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Document Summary
Lobster: transmit disease, crop infestations, key transitions, tissue organ system, symmetry bilateral, body cavity coelomate, development triploblastic protostome, segmentation present, diversity, exoskeleton, chitinous cuticle; protection and mobility, prevent dehydration, segmentation and appendages. Specialized functions; more efficient locomotion: respiration increased metabolism, can breath air/water; more efficient respiration and faster metabolism, sense organs, ex. Tactile, eyes, hearing, balance, chemosensory: complex behaviour, true sociality, ecology, adaptations, metamorphisis, more environmental niches available to same species therefore, more disperse. Skeleton/segments/appendages: groups of segments + tagmata, work together for a common function, head, thorax and abdomen. Subphylum: chelicerata: horseshoe crabs, spiders, ticks, scorpions, sea spiders, 2 tagmata: cepalothorax (head+thorax) and abdomen, appendages: chelicerae (pinchers) and pedipalps/ 4 pairs of walking legs, no mandible jaws, no antennae. Subphylum: myriapoda: one pair of antennae, mandible jaw, centipedes and millipedes, 2 tagmata: head + trunk. Limbs help move the hemolymph around every organ: gills attach to appendages (carbon dioxide or oxygen diffusion, excretory/osmoregulation through antennal glands.
