Phylum Arthropoda
(arthropods)

Phylum Arthropoda (arthropods)

*    Most successful of all animal phyla

*    Everywhere: Terrestrial, aquatic

Phylum Arthropoda (arthropods)

*    Huge group: 70% of all named animal species. At least 1,000,000.

*    80% of arthropods are insects (Class Insecta), and 50% of insects are beetles (Order Coleoptera)

Phylum Arthropoda (arthropods)

*    Closely related to annelids

Phylum Arthropoda (arthropods)

*    General characteristics:

  1) Eucoelomates, bilateral symmetry, protostomes

Phylum Arthropoda (arthropods)

*    General characteristics:

  2) Body segmented. Ancestral trait is many unfused segments. In derived groups, segments fused into functional units (tagmata).

  Regions: head, thorax, abdomen. If head and thorax are fused, called cephalothorax

Phylum Arthropoda (arthropods)

*    General characteristics:

  3) Extreme cephalization (head with many sense organs). Example: compound eye. Made of ommatidia (each a single eye with lens). May also have simple eyes (ocelli) with single lenses.

Phylum Arthropoda (arthropods)

*    General characteristics:

  3) Compound eyes see the world in a different way

  Advantage: detection of ________.

Phylum Arthropoda (arthropods)

*    General characteristics:

  4) Innovation: Have exoskeleton; hard coating of chitin on outside of rest of body

  Secreted by epidermis. Protects against enemies, water loss (on land). Provides attachment points for muscles and organs

Phylum Arthropoda (arthropods)

*    General characteristics:

  Problem: can't grow. Must be shed during molting.

  Problem: will not support large body volume efficiently. Larger body has much greater surface area. Keeps arthropods _______

Phylum Arthropoda (arthropods)

*    General characteristics:

  5) Innovation: Have jointed appendages (legs, antennae, mouthparts) "arthros" (Gr.)=jointed. "podes" (Gr.)=feet

  2 types. Biramous have 2 branches, uniramous have 1 branch

Phylum Arthropoda (arthropods)

*    General characteristics:

  6) Circulatory system _______. Heart pumps blood toward head, then flows back through body

Phylum Arthropoda (arthropods)

*    General characteristics:

  7) Nervous system. Brain small. Ventral ganglia control many body activities

Phylum Arthropoda (arthropods)

*    General characteristics:

  8) Respiratory system

  Terrestrial: Most have spiracles, which open into tracheae that branch into tracheoles

  Some (ex, spiders) have book lungs, leaflike plates in chamber

  Aquatic: ______

Phylum Arthropoda (arthropods)

*    General characteristics:

  9) Excretory system

  Varied. Malphigian tubules bathed in blood, collect fluid, dump wastes in hindgut. Reabsorb water and salts in hindgut

Phylum Arthropoda (arthropods)

*    Chelicerates (subphylum Chelicerata)

  Class Arachnida (arachnids)

  Class Merostomata (horseshoe crabs)

  Class Pycnogonida (sea spiders)

*    Crustaceans (subphylum Crustacea)

  Class Malacostraca (decapods, isopods)

  Class Maxillipoda (barnacles, copepods, others)

*    Uniramians (subphylum Uniramia)

  Class Chilopoda (centipedes)

  Class Diplopoda (millipedes)

  Class Insecta (insects)

 

Phylum Arthropoda (arthropods)

*    Chelicerates (subphylum Chelicerata)

*    First set of appendages modified into fangs or pincers

Phylum Arthropoda (arthropods)

*    Class Arachnida (arachnids)

*    Largest group of chelicerates (57,000 species), mostly terrestrial

*    Carnivores (except many mites are herbivores)

*    Carnivores often pre-digest food by injecting enzymes into prey

Phylum Arthropoda (arthropods)

*    Class Arachnida (arachnids)

*    Lack antennae

*    After chelicerae, next set of appendages are _________.

Phylum Arthropoda (arthropods)

*    Class Arachnida (arachnids)

  Order Opiliones (daddy longlegs)

  Order Scorpiones (scorpions)

  Order Araneae (spiders)

  Order Acari (mites and ticks)

Phylum Arthropoda (arthropods)

*    Order Opiliones (daddy longlegs, harvestmen)

*    5,000 species

*    Oval, compact bodies. Very long, fragile legs

*    Most are predators

Phylum Arthropoda (arthropods)

*    Order Scorpiones (scorpions)

*    1200 species, all terrestrial

*    Tropical, subtropical, desert regions

*    Pedipalps as pincers

*    Abdomen elongated, jointed

*    ________ apparatus at tip (carnivores)

*    Don't lay eggs: young born hatched

Phylum Arthropoda (arthropods)

*    Order Araneae (spiders)

*    35,000 named species, almost all terrestrial

*    Widespread, abundant

Phylum Arthropoda (arthropods)

*    Order Araneae (spiders)

*    ____________. Many use silk (protein) produced from spinnerets to make web (silk stronger than steel)

*    Chelicerae connected to poison glands. Used to paralyze and then predigest prey

*    Note book lung

Phylum Arthropoda (arthropods)

*    Order Acari (mites and ticks)

*    30,000 named species, maybe a million total!

*    Abundant, widespread. All habitats.

Phylum Arthropoda (arthropods)

*    Order Acari (mites and ticks)

*    30,000 named species, maybe a million total!

*    Abundant, widespread. All habitats. Including follicles on ____________ (0.4 mm long)! Eat dead skin. Good news: digestion so efficient, no excretory opening (unusual feature)

Phylum Arthropoda (arthropods)

*    Order Acari (mites and ticks)

*    Dust mites(<0.2 mm long) that eat skin scales, in sheets and house dust

*    ____ shed 400,000 skin scales/minute!

*    Most have cephalothorax and abdomen fused to make unsegmented, oval body

 

Phylum Arthropoda (arthropods)

*    Order Acari (mites and ticks)

*    Ticks: ectoparasites, feed on blood

*    Relatively large

 

Phylum Arthropoda (arthropods)

*    Order Acari (mites and ticks)

*    Ticks: ectoparasites, feed on blood

*    Main problem: carry diseases. Ex, Lyme disease (caused by spirochaetes, spiral bacteria)

 

Phylum Arthropoda (arthropods)

*    Chelicerates (subphylum Chelicerata)

*    First set of appendages modified into fangs or pincers (chelicerae)

Phylum Arthropoda (arthropods)

*    Chelicerates (subphylum Chelicerata)

*    First set of appendages modified into fangs or pincers (chelicerae)

*    Class Arachnida (arachnids)

*    Class Merostomata (horseshoe crabs)

*    Class Pycnogonida (sea spiders)

Phylum Arthropoda (arthropods)

*    Class Merostomata (horseshoe crabs)

*    Marine, 5 living species.

Phylum Arthropoda (arthropods)

*    "Living fossils": identical fossils from up to _____ million years ago.

Phylum Arthropoda (arthropods)

*    Class Merostomata (horseshoe crabs)

*    Note carapace, cephalothorax, abdomen, telson, book gills, chelicerae and pedipalps

Phylum Arthropoda (arthropods)

*    Class Merostomata (horseshoe crabs)

*    Predators, eat worms and mollusks

Phylum Arthropoda (arthropods)

*    Class Pycnogonida (sea spiders)

*    1000 species, marine. Not closely related to other chelicerates

*    Small size

Phylum Arthropoda (arthropods)

*    Class Pycnogonida (sea spiders)

*    External parasites or predators

*    Often ____ pairs of legs (hence "spider" common name)

*    No excretory or respiratory systems

Phylum Arthropoda (arthropods)

*    Chelicerates (subphylum Chelicerata)

  Class Arachnida (arachnids)

  Class Merostomata (horseshoe crabs)

  Class Pycnogonida (sea spiders)

*    Crustaceans (subphylum Crustacea)

  Class Malacostraca (decapods, isopods)

  Class Maxillipoda (barnacles, copepods, others)

*    Uniramians (subphylum Uniramia)

  Class Chilopoda (centipedes)

  Class Diplopoda (millipedes)

  Class Insecta (insects)

 

Phylum Arthropoda (arthropods)

*    Crustaceans (subphylum Crustacea)

*    Each segment has appendages

*    Usually _____ pairs antennae

*    Also 3 types of chewing appendages (mandibles), varying pairs of legs.

Phylum Arthropoda (arthropods)

*    Crustaceans (subphylum Crustacea)

*    Mandibulate appendages biramous: have 2 branches to them. Endopodite and exopodite

Phylum Arthropoda (arthropods)

*    Crustaceans (subphylum Crustacea)

*    Breathe with gills

*    Nauplius larva: 3 pairs of appendages, metamorphoses through stages to become adult

Phylum Arthropoda (arthropods)

*    Often have compound eyes (sometimes on stalks)

*    Usually _____________

Phylum Arthropoda (arthropods)

*    Class Malacostraca (diverse: 20,000 species)

  Order Decapoda (decapods). Almost all aquatic.

  5 sets of well-developed pairs legs/claws (deca=10, pod=foot)

Phylum Arthropoda (arthropods)

*    Class Malacostraca (diverse: 20,000 species)

  Cephalothorax covered by carapace. Exoskeleton strengthened by carbonates

  Shrimps, lobsters, crabs, crayfish

Phylum Arthropoda (arthropods)

*    Class Malacostraca (diverse: 20,000 species)

  Under abdomen: appendages called _________________

Phylum Arthropoda (arthropods)

*    Class Malacostraca (diverse: 20,000 species)

  Order Isopoda (isopods): about 50% of the 4500 species are terrestrial (moist habitats). Others deep in ocean.

  Most body segments have similar-looking legs

  Pillbugs (roll up), sowbugs

Phylum Arthropoda (arthropods)

*    Class Maxillopoda (small size)

  Include barnacles, copepods, others

  Barnacles: sessile! cement heads to substrate, feed with appendages. Protect body with calcareous plates.

  Hermaphroditic, but not at same time. Males must fertilize females internally. _________ longest relative to body size of any animal: up to 10 times body length.

Phylum Arthropoda (arthropods)

*    Class Maxillopoda (small size)

  Copepods: tiny, but among most abundant multicellular organisms on earth (important part of plankton)

  Some specialized as parasites

Phylum Arthropoda (arthropods)

*    Chelicerates (subphylum Chelicerata)

  Class Arachnida (arachnids)

  Class Merostomata (horseshoe crabs)

  Class Pycnogonida (sea spiders)

*    Crustaceans (subphylum Crustacea)

  Class Malacostraca

  Class Maxillipoda

*    Uniramians (subphylum Uniramia)

  Class Chilopoda (centipedes)

  Class Diplopoda (millipedes)

  Class Insecta (insects)

 

Phylum Arthropoda (arthropods)

*    Subphylum Uniramia

*    Mouthparts are mandibles

*    Mandibulate appendages _______________

*    Breathe through tracheae, have Malphigian tubules to excrete wastes

*    Mostly terrestrial (or freshwater), few marine

Phylum Arthropoda (arthropods)

*    Subphylum Uniramia

*    Class Chilopoda (centipedes)

*    Class Diplopoda (millipedes)

*    Class Insecta (insects)

Phylum Arthropoda (arthropods)

*    Class Chilopoda (centipedes)

*    2500 species, terrestrial

*    Head followed by many similar segments, each with appendages

*    One pair legs per segment

 

Phylum Arthropoda (arthropods)

*    Class Chilopoda (centipedes)

*    Carnivores (most eat insects)

*    Appendages on first trunk segment: __________________

*    Bites can be dangerous to humans

 

Phylum Arthropoda (arthropods)

*    Class Diplopoda (millipedes)

*    10,000 species, terrestrial

*    Head followed by many similar segments, each with appendages

*    Two pairs legs per segment

 

Phylum Arthropoda (arthropods)

*    Class Diplopoda (millipedes)

*    Herbivores/detritivores with chewing mouthparts (no fangs on 1st segment)

*    Each segment with glands: make ___________ fluid (defense)

 

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Largest group: number species, number individuals (one billion billion, 1018, living individuals on planet)

*    All habitats, except few marine

 

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    1) 3 body sections: head, thorax, abdomen

*    2) 3 pairs of legs attached to thorax

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    3) Mouthparts: ________, pair maxillae, pair mandibles, labium (fused pair appendages)

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    3) Mouthparts modified for various feeding modes

 

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    4) Compound eyes, often ocelli

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    5) Often one or two pairs of wings (on thorax)

  Sometimes first pair thick and hard (elytra: beetles)

  Sometimes wings covered with scales (butterflies/moths)

 

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    6) Other senses

  sensory hairs (can detect sounds, chemicals). ___________: chemicals used for communication (find mates, mark trails, etc.)

  tympanal organs: sound detection (grasshoppers, crickets, cicadas, some moths).......Moths??

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    6) Other senses

  tympanal organs: moths detect bat ___________ and do evasive maneuvers

 

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    7) Development

  Metamorphosis: simple (top) or complete. Larval stages called _______

Phylum Arthropoda (arthropods)

*    Class Insecta (insects)

*    Features:

*    7) Development

  Metamorphosis: complete example. Caterpillar goes through instars, pupates, becomes butterfly (monarch).

Phylum Arthropoda (arthropods)

*    Major insect orders

  Coleoptera (beetles): Chewing mouthparts. _______ cover hind wings. Most species (350,000 named)

 

Phylum Arthropoda (arthropods)

*    Major insect orders

  Diptera (flies): _________ wings. Hind wings reduced to knobs. Larva legless maggots (complete metamorphosis)

  Ex, carrion flies. Used to tell how long bodies have been dead!

 

Phylum Arthropoda (arthropods)

*    Major insect orders

  Lepidoptera (butterflies, moths): Broad scaly wings, ________ mouthparts, complete metamorphosis (larvae are caterpillars)

 

 

Phylum Arthropoda (arthropods)

*    Major insect orders

  Hymenoptera (bees, wasps, ants): Many can sting, ________ transparent wings.

  Some are social: form complex societies with specialized tasks for certain individuals (males only present briefly)

Phylum Arthropoda (arthropods)

*    Major insect orders

  Hemiptera (true bugs, leafhoppers): Piercing sucking mouthparts, usu. 2 pairs wings

Phylum Arthropoda (arthropods)

*    Major insect orders

  Orthoptera (grasshoppers, crickets, roaches): Some can jump

Phylum Arthropoda (arthropods)

*    Major insect orders

  Odonata (dragonflies and damselflies): 2 pairs of wings, ___________. Aerial predators as adults, aquatic predators as larvae.

Phylum Arthropoda (arthropods)

*    Major insect orders

  Isoptera (termites): social with complex societies, eat wood (digested by protists). Some make aboveground nests.

Phylum Arthropoda (arthropods)

*    Major insect orders

  Siphonaptera (fleas): wingless, small, laterally flattened body, vertebrate ectoparasites

  Can carry disease. Ex, bubonic plague (bacterium). Killed almost ______% of Europeans in the 1300s. Carried by rat fleas.

Phylum Arthropoda (arthropods)

*    Major insect orders

  Plague still around.

Phylum Arthropoda (arthropods)

*    Major insect orders

  Anopleura (lice): ____________, dorsoventrally flattened body, vertebrate ectoparasites