Phyla Onychophora and Arthropoda

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Onychophora

Arthropoda

Phylum Onychophora

Phylum Arthropoda

Jointed exoskeleton of chitin

Trachea

Malpighian tubules

Specialization of segments

Systems

Arthropod Systems

IntegumentaryIntegumentary- one cell layer epidermis, secretes exoskeleton of chitin.

Skeletal- jointed exoskeleton of chitin; must be molted for growth, very protective, but not supportative.

MuscleMuscle- striated muscle and very complex for moving skeleton; hydrostatic.

DigestiveDigestive- complex and complete, mouthparts and gut modified for food source.

Systems continue

Arthropod Systems continues ExcretoryExcretory - coxal glands; green glands;

Malpighian tubules RespiratoryRespiratory - book gills, book lungs,

tracheae. CirculatoryCirculatory- open with dorsal heart;

circulatory not used to transport oxygen in many species.

NervousNervous- Dorsal brain; ventral double nerve cord with ganglia each segment; most behavior innate.

Systems continue

Arthropod Systems continues EndocrineEndocrine- most hormones neural in origin; molting

controlled by hormones, ecdysone and juvenile hormone.

ReproductiveReproductive Varied, mostly dioecious, usually sexual dimorphism;

complex life cycles; usually adult and larva do not compete for food.

Fertilization mostly internal Development

• Direct development• Hemimetabolous (incomplete)metamorphosis• Holometabolous (complete) metamorphosis.

Systems continue

Phylum Arthropoda Subphylum- Trilobita

Subphylum- Chelicerata

Subphylum- Crustacea

Subphylum- Uniramia (not on this power

point presentation)

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Subphylum Trilobita

Extinct

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Subphylum Chelicerata (key-lis-er-a-ta)

Class: Merostomata (mer-o-sto-ma-ta)• Limulus (horseshoe crab)

Class: Pycnogonida (pick-no-gon-I-da) Sea spiders

Class: Arachnida (a-rack-ni-da) Spiders, tick,mites, scorpions etc.

Phylum Arthropoda

Class: Merostomata Limulus

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Class: Pycnogonida

Sea spiders

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Class: Arachnida Order: Araneae (a-ran-e-e)

• Latrodectus (black widow spider)

• Loxosceles reclusa (fiddle-back spider or brown recluse)

Order: Scorpionida (scorn-p-on-Ida)• Scorpions

Order: Opiliones (o-pil-e-on-i-da)• Harvestmen or daddy longlegs

Order: Acari (ac-kar-i)• Ticks and mites

Order: Pseudoscorpionida• pseudoscorpions

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Order Araneae Spiders

Loxosceles reclusa

Latrodectus

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Order: Scorpionida

Scorpions

Ventral

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Order: Opiliones Harvestmen (daddy longlegs)

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Order: Acari

Ticks and mites

femalemale

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Order: Pseudoscorpionida

About 2,000 species of false scorpionsThe largest species reaches a length of only 7 mm

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Subphylum Crustacea Class: Maxillopoda (subclass Cirripedia)

• barnacles

Class: MalacostracaMalacostraca Order: Isopoda

• pill bugs Order Amphipoda Order: Decapoda

• Cambarus (Procambarus) - Crayfish

Class: BranchiopodaBranchiopoda Crayfish dissectionCrayfish dissection• Tadpole shrimp

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Class: Maxillopoda Subclass: Cirripedia

Barnacles

Gooseneck barnacles Acorn barnacles

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Class: Malacostraca Order Isopoda

pill bugs

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Order Amphipoda

Class Malacostraca

Order: Decapoda

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Crayfish Dissection

Sex determinationCrayfish appendages

Mouth partsAll appendages

Crayfish Internal

Return to Decapoda

Sex determination

FemaleFemale

MaleMale

Crayfish dissection

Cambarus dissection internal

Crayfish dissection

Cambarus dissection mouth appendages Crayfish dissection

Cambarus dissection All appendages

Crayfish dissection

Branchiopoda Tadpole shrimp

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