Transcript Platyhelminthes, Nematodes, molluscs

BSC 2011L
Phylum Nematoda
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Aquatic habitats, damp soil
Parasitize both plants and animals
Pinworms and hookworms cause intestinal
problems in humans and other animals
Trichonella causes trichonosis (attaches to
intestinal wall and robs host of nutrients)
One species causes what we call
elephantiasis
Digestion – mouth and anus
Circulation - none
Phylum Nematoda
Phylum Nematoda
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Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
Roundworm
bilateral
pseudocoelomate
mouth and anus
none, fluid in pseudocoel
none
none
dorsal and ventral nerve cord
parasitic
diffusion through body surface
2 lateral tubes
longitudinal muscles, whipping motion
hydrostatic skeleton, pseudocoel
Phylum Arthropoda
Paired, jointed appendages
 Exoskeleton made of chitin
 Digestion – complete
 Circulation - open
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Phylum Arthropoda
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Chelicerates
 Horseshoe crabs
 Arachnids – spiders, ticks, scorpians
○ 4 pairs of legs
Phylum Arthropoda
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Crustaceans
 crabs, shrimp, lobster, crayfish
○ 3-5 pairs of legs
Phylum Arthropoda
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Crayfish dissection
 Male vs. female
Phylum Arthropoda
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Insects and relatives – breathe by
trachea
 Chilopoda – centipedes
○ 1 pair of legs per segment
 Diplopoda
○ 2 pairs of legs per segment
 Insecta/Hexapods –
○ 3 pairs of legs
Phylum Arthropoda
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Class Insecta
 Grasshopper
Phylum Arthropoda
Class Crustacea
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Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
crayfish
bilateral
coelomate – protostome
complete
open, heart, blood vessels
yes
mouth parts, walking legs, swimmerets
dorsal brain, ventral nerve cord
aquatic
gills
green gland, gills
walking legs
exoskeleton
Phylum Arthropoda
Class Insecta
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Animal:
Symmetry:
Body cavity:
Digestion:
etc.
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
Grasshopper
bilatera
coelomate – protostome
complete – mouth, crop, gizzard, stomach,
open,
yes
mouth parts, antennae, walking legs
dorsal brain, ventral nerve cord
terrestrial
tracheal tubes opening at spiracles
malpighian tubes, empty to intestine
2 pairs of wings, walking legs
exoskeleton
Grasshopper model
Crayfish Dissection
Gills have been
Removed in drawing