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Ecdyzoa group:
Nematoda and Arthropoda
They have a cuticle that must be molted via ecdysis
Nematods are pseudocoelomates and have no segmentation
Arthropods are coelomates and have segmented bodies
Phylum Arthropoda: jointed appendages
Abundance: There are about a billion billion arthropods
Diversity: 2/3 species is an arthropod
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Segmented body with appendages
Segments fused and
Appendages became specialized (division of labor)
Arthropods secrete to success Arthropods secrete to success
Exoskeleton (cuticle with chitin and hardened by protein matrix)
structural support, protection, prevention from water loss
levers for muscle attachment and movement
joints (areas where cuticle is thin) provide flexibility
Need to molt allowed for:
Metamorphosis
radical change in form between larva and adult
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Limitations of being an arthropod
Phylum Onychophora: Velvet worms
Phylum Tardigrada: Water bears
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Phylum Arthropoda: arthropods
Subphylum Myriapoda: millipedes and centipedes
Subphylum Chelicerata: spiders, scorpions, ticks, mites
Subphylum Crustacea: Crayfish, crabs, shrimps, barnacle, roly-poly
Subphylum Hexapoda: insects and relatives
Subphylum Myriapoda:
Body divided in 2 regions:
Head and trunk
Young resemble adults
No metamorphosis
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Subphylum Myriapoda: Class Chilopoda: centipedes
Have flattened bodies with up to 177 segments
Each segment bears ONE PAIR of jointed legs
appendages of first body segment form poison claws
Head has one pair of antennae, a pair of mandibles, and one or two pairs of
maxillae
Predators, most harmless to humans
Young resemble adults and do not undergo metamorphosis
Subphylum Myriapoda: Class Diplopoda: millipedes
- Less active than centipedes
Walk with graceful rather than wriggling motion
- Scavengers: most eat decayed plants but a few eat living plant tissue
- Most are slow moving and roll into a coil for defense
- Some secrete toxic or repellant fluids
- Cylindrical bodies with 25 to more than 100 segments
Most segments have two pairs of legs
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Kingdom Animalia:
Phylum Arthropoda
(Subphyllum Chelicerata)
Subphylum Chelicerata: arthropods with claws
Body divided in 2 regions:
Cephalothorax (sensory, feeding, locomotor)
abdomen (visceral functions)
1stpair of appendages are chelicerae (feed/defense)
2ndpair are pedipalps(sensory)
Lack mandibles and antennae
Most suck liquid food from prey
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Class Merostomata: Horseshoe crabs - Marine in shallow waters, come to shore to mate
- Feed on worms and mollusks
- Unchanged for 250 million years
- Unsegmented carapace covers body
- Cephalothorax: 5 pairs of walking legs and
1 pair of chelicerae
- Abdomen bears six pairs of thin appendages
- Carapace has 2 compound and 2 simple eyes
Why this crab's blood could save your life
http://www.cnn.com/2014/09/04/health/this-crabs-blood-could-save-your-life/
Horseshoe crab blood can detect and trap bacterial toxins
Its blood is harvested for a test to ensure medical products are not
contaminated.
45 minutes of exposure to the crab's blood is enough to reveal bacteria
contamination which otherwise avoid detection
It is sensitive enough to isolate a threat the equivalent size of a grain of sand in
a swimming pool.
The U.S. Food and Drug Administration (FDA) requires that intravenous drugs
and any medical equipment coming in contact with the body must first pass
through the crab's blood, from needles to surgical implants including
pacemakers.
As a result, thousands more of us survive such procedures.
Up to 600,000 crabs are captured each year for their blood Between
10-30% of donor crabs die in the process
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Class Arachnida: Spiders, scorpions, ticks and others
• Cephalothorax:
a pair of chelicerae, a pair of pedipalps, and 4 pairs of walking legs
• In spiders abdomen spinning glands
• Most are predators and have claws, fangs, poison glands, or stingers
• Pedipalps of males are modified for sperm transfer
• Most harmless to humans and provide essential control of injurious insects
• Ticks may carry human diseases
(Lyme disease)
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Kingdom Animalia:
Phylum Arthropoda
(Subphylum Crustacea)
Subphylum Crustacea: crustaceans Body divided in 2 regions:
Cephalothorax (sensory, feeding, locomotion)
may be covered by ________, has 2 pairs of antennae
Abdomen with swimmerets and uropod (swimming, reproduction and breathing)
Biramous appendages (branched)
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Crayfish dissection: External anatomy Crayfish dissection: Internal anatomy
Labeled structures include one of the two green glands (1) that
function in osmoregulation and excretion, one of the
compound eyes (2), the digestive gland (3), one of the two sets
of mandibular muscles (4) that control the mandibles, the gills
(5), a portion of the abdominal extensor muscle (6), a portion of
the fifth walking leg (7) and one of the third maxillipeds (8).
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Crayfish dissection: Internal anatomy Class Maxillopoda: barnacles and copepods
• Copepods are small in size and lack abdominal appendages
• Main component of zooplankton
• ½ species are parasites of other marine animals
• Most feed with their maxillae
but barnacles use their legs for filter feeding,
.
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Class Malacostraca:
Crayfish, lobsters, crabs , shrimp , krill and pill bugs
Marine, freshwater and land
Most species are scavengers, although some,
are filter feeders (porcelain crab)
are carnivores (mantis shrimp)
are parasites (isopods)
Note that in crabs the abdomen is folded under cephalothorax
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Phylum Arthropoda: arthropods
Subphylum Myriapoda: millipedes and centipedes
Subphylum Chelicerata: spiders, scorpions, ticks, mites
Subphylum Crustacea: Crayfish, crabs, shrimps, barnacle, roly-poly
Subphylum Hexapoda: insects and relatives
Subphylum Hexapoda: Body divided in 3 regions:
Head, thorax and abdomen
3 pairs of legs
Class Insecta:
Mouth appendages exposed
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No metamorphosis
Order Thysanura
SILVERFISH
Wingless, walking legs
Caudal filaments
Chewing mouthparts
Incomplete metamorphosis
with chewing mouthparts
Order Orthoptera
Grasshoppers , crickets, roaches
2 pairs of wings (forewings are leathery)
jumping hind legs
Order Isoptera
Termites
2 pairs of wings that are the same
Order Odonata
Dragonflies and damselfies
2 pairs of wings with primitive venation
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INCOMPLETE METAMORPHOSIS with sucking mouthparts
Order Hemiptera
True bugs
2 pairs of wings (forewings are half hard)
Grasshopper: external anatomy
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Grasshopper: internal anatomy
COMPLETE METAMORPHOSIS WITH SIPHONING MOUTHPARTS
Order Lepidoptera
Butterflies and moths
Wings with scales
walking legs
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COMPLETE METAMORPHOSIS WITH REDUCED HIND WINGS (HALTERES)
Order Diptera
Flies
Sponging mouthparts
Maggot therapy
Mosquitoes
Piercing sucking mouthparts
COMPLETE METAMORPHOSIS WITH CHEWING MOUTHPARTS
Order Coleoptera
BEETLES
Forewings hardened (elytra),
2nd pair of wings
walking legs
Order Hymenoptera
ANTS, BEES, WASPS
2nd pair of wings
Abdomen with a waist, wings membranous,
lapping-chewing mouthparts
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Insects for food and as food
