Arthropoda, Echinodermata & Mollusca Notes PDF

# Arthropoda (joint-foot) ## Subphyla ### Trilobita - Oldest (Cambrian period) - Extinct ### Chelicerata - Cephalothorax: - Anterior - brain, eye, mouth, esophagus - Posterior - front of digestive system, pairs of legs - Abdomen: internal organs - Mouthpart: - 1st pair - Chelicerae...

# Arthropoda (joint-foot) ## Subphyla ### Trilobita - Oldest (Cambrian period) - Extinct ### Chelicerata - Cephalothorax: - Anterior - brain, eye, mouth, esophagus - Posterior - front of digestive system, pairs of legs - Abdomen: internal organs - Mouthpart: - 1st pair - Chelicerae - 2nd pair = Pedipalps (longer) - No "feelers" on head - Respires: book gills, book lungs, tracheal tubes 1. **Eurypterids** - Extinct, 3m long 2. **Horseshoe Crabs** - 5 species - 5 pair walking legs, long telson 3. **Arachnids** - Cephalothorax: 4 pairs of legs - Pedipalps for capture prey - Chelicerae for biting - Respires through book lungs, tracheal tubes - a) Spiders - b) Mites & Ticks - c) Scorpions ### Crustacea - Aquatic - Carnivores, filter feeders, parasitic - Appendages - 1st 2 pairs: feelers, sensory hairs - 3rd pair: mandible (mouthpart) - Thorax: abdomen; legs/internal fertilization/feeding - **Crayfish** - i) Claws - ii) 4 pairs of legs - iii) Swimmerets - iv) Pedipalle like appendages - v) Flat tail ## Uniramia 1. **Centipedes:** carnivores - Pair of poison claws in head region - Eat arthropods, toads, snakes, mice - 1 pair legs per segment (except first and last 3 segments) 2. **Millipedes:** detritus feeders - 2 pairs of legs per segment - Live under decaying logs (moist) - Protection: roll into ball, excrete toxic chemicals 3. **Insects** - 3 part body - a) Head - 3 pairs of legs at thorax - 1 pair antennae, 1 pair compound eye - 2 pair wings on thorax - b) Thorax - c) Abdomen - Tracheal tubes for respire - Bees: leg hairs collect pollen, saliva change nectar into honey (easier to digest) - Special large muscles for wings require ATP -> oversized mitochondria # Echinodermata (spiny-skin) - Sport radial symmetry - Endo skeleton - Closely related to humans - Share certain stages of development as chordates -> enclostaetateor | Respiration | Nervous | Excretion | Movement | Reproduction | | ---------------------------------------- | --------------------- | --------------- | ----------------------------------------------------- | ------------ | | Diffusion through thin-walled fosve | No head | Digestion: solid | Be feet and thin layer of muscle fibres | Frost divecious | | Some have stengills | Chemoreceptors | Brittle stars: | Out anus | | | | Nerve rings around | | | - Some monoecious | | mouth & radial | | | - Starfish gametes | | Light sensitive cells | | | - Gametes release | | | In eyespot at the end | | | - External fertilzation | | | of each arm | | | - Larvae swim | | | | | | - Develop bilateral sym | | | | | | - Metre, metamorphesize | | | | | | - Into adults | | | | | | - Caxxual.regenerate | ## Starfish - **Asteroidea** - Incanthester planci (Crown-of-thorns) - Solaster dansoni (sun star) - Tube feet ## Brittle Stars - **Ophiuroidea** - Filter feeder - Detritus feeder - No arms - Shed arms when attached ## Sea Urchins, Sand Dollars - **Echinoidea** - Cut algae solely - Detritus ## Sea Cucumber - **Hologthuroidea** - Modified tube feet - Tentacles ## Sea Lilies, Feather Stars - **Crinoiden** - Filter feeders ## Water Vascaloilla System - Ampullae - Tube feet - Nusuclature ## Mollusca ### Polyplacophora - **Examples:** - Chitin | Diagram | Digestion | Circulatory | Respiratory | Nervous | Reproduction | | :------ | :-------- | :----------- | :----------- | :------------- | :------------ | | Valves | Gut radula | Open | Gills | Simple | External | | 0000 | | Sinuses - vessel inside | | Chemical, egg & sperm | | | | | Vessel monte | | Touch, ocelli | | | | | Heart gills cavity | | Statocyst | | | | | | | | Larvae (Hocoplan) | | Radila | | | | | | | Mantle | | | | | | | Flat | | | | | | ### Gastropoda (stomach-foot) - **Example:** - Snails, sea slugs - Nudibranchs - No valve - Not coiled - Shell - Mantle - Cavity - Tadula - Foot | Diagram | Digestion | Circulatory | Respiratory | Nervous | Reproduction | | :------ | :-------- | :----------- | :----------- | :------------- | :------------ | | | Rach la | Open | Gills | Simple | External | ### Bivalvia - **Example:** - Scallops - Clams, oysters, but - Mmmk - Shell siphon | Diagram | Digestion | Circulatory | Respiratory | Nervous | Reproduction | | :------ | :-------- | :----------- | :----------- | :------------- | :------------ | | | | Open | Use siphon | Simple | External | | | | | Gills | | | | | | | (Internal) | | | ### Cephalopoda - **Example:** - Nautilus (external) - 80-90 tentacles - Decapods (internal) - Squid, cuttlefish - 8 short, 2 long - Octopods (prone) - *Fentacles - Octopus | Diagram | Digestion | Circulatory | Respiratory | Nervous | Reproduction | | :------ | :-------- | :----------- | :----------- | :------ | :----------- | | Mn | Gut | Closed | Gills, | Developed | Internal | | Foot | | | expelled | sight - | | | 8 arms | | | through | dioecion | | | Mantle | | | siphon | texture | | | Carily | | | | by touch | | | Siphon | | | | Chroma- | | | Beak | | | | phores | | | Chromatophores | | | | inteligent | | | Fent les | | | | | |