Post on 24-Feb-2016
description
Invertebrates Phylum Annelida Segmented Worms
◦ segmentation allows specialization of system
Body Plan: Tube-within-a-tube
Body Systems◦ Digestion
Pharynx, esophagus, crop, gizzard, intestine, accessory glands◦ Musculatory
Longitudinal and circular muscles in each segment◦ Circulatory
Closed system with pumping hearts◦ Nervous system
brain, ventral nerve cord, and ganglia in each segment◦ Excretory system
nephridia in most segments
Annelida cont’dClass Polychaeta
◦Largest class - marine worms◦Have setae-bristles for anchoring
worm or helping in locomotion Arranged in bundles on parapodia
Swimming, gas exchange◦Polychaetes are seasonal breeders
After fertilization, a trochophore larva develops-same larval type as molluscs
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Annelida cont’dClass Polychaeta cont’d
◦Representative Organisms Clam worms-Nereis
Predators-eat crustaceans and other small animals
Tube worms Tentacles that form a funnel-shaped fan Sessile filter feeders
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Polychaete diversity
Fig. 30.13
Annelida cont’dClass Oligochaeta
◦Earthworms◦Few setae per segment◦No obvious head◦Gas exchange across body wall◦Feed on leaves and other organic
matter Food is drawn into mouth by muscular
movements Digestive tract has a large surface area
Typhlosole-expanded region on dorsal surface of intestine
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Earthworm, LumbricusFig. 30.14
Annelida cont’dClass Oligochaeta cont’d
◦Segmentation Structure
External - evident by body rings Internal - septa
Nervous System Ventral nerve cord has ganglionic swellings in each
segment Lateral nerves extend from ganglions
Excretory Paired nephridia in each segment
1st funnel-like collects coelomic fluid 2nd exits through body wall
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Annelida cont’dClass Oligochaeta cont’d
◦Segmentation cont’d Circulation
Blood moves anteriorly through dorsal vessel Enters aortic arches- “hearts” Pump blood to ventral vessel
blood then moves posteriorly Branches in each segment
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Annelida cont’dClass Oligochaeta cont’d
◦Reproduction in earthworms Hermaphroditic
Male organs- testes, seminal vesicles, sperm ducts
Female organs-ovaries, oviducts, seminal receptacles
Worms lie parallel in opposite directions Clitellum produces mucus to keep sperm moist
After separation, produces a slime tube which moves eggs and sperm together for fertilization
Slime tube then produces a cocoon
Annelida cont’dClass Hirudinea
◦Leeches◦Most live in freshwater◦Most are ectoparasites- have suckers for
feeding Saliva contains hirudin-anticoagulant
◦Have same general body plan as other annelids Lack setae Each body ring has transverse grooves
Makes leech appear to have more segments
Invertebrates Phylum ArthropodaExoskeleton of chitin
◦ Must undergo molting to allow growth
Exhibit jointed appendages◦ Walking, swimming, reproduction, eating, sensory
reception
3 body regions◦ Head, thorax, abdomen
Well-developed nervous system◦ Brain and ventral nerve cord◦ Sense organs-compound eyes, antennae
Arthropod diversity
Fig. 30.15
Phylum Arthropoda cont’d.Subphylum
Crustacea◦ Barnacles,
shrimps, lobsters, crabs, crayfish
◦ Terrestrial - sowbug
Phylum Arthropoda cont’d.Subphylum Crustacea cont’d
◦Crayfish: Representative external structure Fused cephalothorax
Head has compound eyes and 5 pairs of appendages First 2 pairs are antennae, 3 pair are mouth
parts Thorax has 5 pair of appendages-walking legs
1st walking leg has a pinching claw Gills are situated above the walking legs
Abdomen- has swimmerets Last 2 segments have uropods and telson
Phylum Arthropoda cont’d.Subphylum Crustacea cont’d
◦Crayfish: Representative internal structure Digestive system
2 part stomach, green glands for waste excretion
Vascular system heart pumps blood with hemocyanin into
hemocoel Hemocyanin has blue pigment Hemolymph flows around organs
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Phylum Arthropoda cont’d.Subphylum Crustacea cont’d
◦Crayfish: Representative internal structure cont’d Nervous system
Brain and ventral nerve cord with segmental ganglia Sensitive hair like receptors on antennae
Mechanoreceptors: responds to physical stimuli Chemoreceptors: sensitive to chemicals in the water
Reproduction Sexes separate- sperm transfer by first pair of
swimmerets Ovaries open at base of third walking legs After fertilization, eggs attach to swimmerets of female
Male crayfish, Cambarus
Fig. 30.16
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Phylum Arthropoda cont’d.Subphylum Uniramia
◦Insects; largest and most diverse group
◦General structure Head with pair of compound eyes or
several simple eyes, a pair of antennae, mouthparts adapted to specific way of life
Thorax: 3 pairs of legs and wings if present
Abdomen: contains internal organs
Phylum Arthropoda cont’d.Subphylum Uniramia cont’d
◦Representative Organism: Grasshopper 3rd pair of legs is adapted for jumping 2 pairs of wings Tympanum on side of first segment of
abdomen Ovipositor of females- for digging a hole
in which to lay eggs.
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Phylum Arthropoda cont’d.Subphylum Uniramia cont’d
◦Grasshopper cont’d. Internal organs
Digestive system-stomach, intestine, rectum, anus
Excretory system - Malpighian tubules Uric acid-nitrogenous waste
Respiratory system-spiracles lead into trachae Air pumped by contraction and relaxation of
body wall Circulatory system-heart pumps hemolymph
into aorta, leads to a hemocoel Hemolymph has no specialized pigment and is
colorless
Phylum Arthropoda cont’d.Subphylum Uniramia cont’d
◦Grasshopper cont’d. Reproduction
Adapted to terrestrial life Internal fertilization protects zygotes and
gametes from drying Penis inserted into female, sperm stored in
seminal receptacle Fertilized eggs are deposited into ground
Metamorphosis change in form and physiology that occurs as a
larva becomes and adult Immature grasshopper called nymph
Female grasshoppers
Fig. 30.18 30-22
Phylum Arthropoda cont’d.
◦ Grasshopper: terrestrial Spiracles and trachae
for gas exchange O2 diffuses directly
through to reach cells Has tympanum for
reception of sound Use legs for hopping
and wings for flying Penis for passing
sperm to female to prevent drying
◦ Crayfish: aquatic Crayfish gills for
gas exchange require oxygen-
carrying pigment to carry oxygen to cells
Hair like receptors Utilize uropods for
swimming Sperm passed to
female, eggs carried externally.
Comparing Subphyla Uniramia and Crustacea
Phylum Arthropoda cont’d.Subphylum Chelicerata
◦Arachnids: Spiders, ticks, scorpions, mites
◦Cephalothorax 6 pairs of appendages Chelicerae, pedipalps, and 4 pairs of
walking legs◦Abdomen contains internal organs◦Ticks and mites are ectoparasites
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Phylum Arthropoda cont’d.Subphylum Chelicerata cont’d
◦Representative Organism: Spiders Narrow waist separates cephalothorax from
abdomen Fangs deliver poison to prey Pedipalps sense and hold prey Digestion:
Digestive juices released into prey, initial digestion is external
digested “broth” then is sucked into stomach Gas Exchange
lamellae of inner body wall for gas exchange “book lungs”
Silk glands for web-spinning
Arachnid diversity
Fig. 30.19
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