Phylum ARTHROPODA

The most successful animal group to have ever lived

Phylum Arthropoda

  ARTHRO (joint) + PODA (foot) have “jointed feet”

  jointed appendages (legs & other outgrowths)

  chitinous exoskeleton for protection, but restricts size MOLTING

  bilateral symmetry, triploblastic, coelomate

Phylum Arthropoda

  body segmented forming specific body regions

Structure and Function

  Feeding – complete digestive tract   Internal transport – open circulatory

system w/ dorsal heart   Respiration – varied   Excretion – varied   Nervous system – brain + ventral nerve

cord; sense organs (sight, smell, hearing, balance, taste, touch, etc.)

Structure and Function

  Reproduction – sexes separate

Taxonomy of Phylum Arthropoda   Subphylum TRILOBITA

  Subphylum CHELICERATA

  Subphylum CRUSTACEA

  Subphylum UNIRAMIA  Class CHILOPODA  Class DIPLOPODA  Class INSECTA

Subphylum TRILOBITA

  early arthropods all extinct   pronounced segmentation   little or no variation in appendages

Subphylum CHELICERATA

  CHEILOS (lips) + CHEIR (arm)   cepalothorax & abdomen   no antennae   6 pairs of appendages:

chelicerae – claw-like, for feeding (pincers or fangs)

pedipalps – sense chemicals, touch; for holding food, sperm transfer in males

walking legs – 4 pairs

Subphylum CHELICERATA

  respiration: book lungs   e.g. spider scorprion tick & mite horseshoe crab

Subphylum CRUSTACEA   two pairs of antennae   cephalothorax & abdomen   most marine, some freshwater; few

terrestrial   e.g. lobster, crab, shrimp

waterflea, barnacle, crayfish

Structure & Function of the Crayfish

  paired appendages: antennules, antennae, maxillipeds, chelipeds, walking legs, swimmerets, uropods capable of self-amputation & regeneration

Structure & Function of the Crayfish   excretion: green glands   circulation & respiration: heart

arteries sinuses gills   sense organs: compound eyes,

antennules, antennae, statocyst   reproduction: dioecious; fertilized eggs

attach to female’s swimmerets… young, too (for a while)

Subphylum UNIRAMIA

  one pair of antennae uniramous (unbranched)

  jaw-like mandibles for feeding   compound eyes

Subphylum UNIRAMIA

Class Chilopoda •  w/ head & worm-like body made up of

similar segments •  segments have one pair of legs •  head w/ one pair of antennae & various

mouthparts •  e.g. centipede (“hundred legger”)

Centipede

Subphylum UNIRAMIA

Class Diplodopa •  distinct head w/ worm like body •  two pairs of legs per segment •  head w/ one pair of antennae &

mouthparts •  e.g. millipede (“thousand legger”)

Millipede

Subphylum UNIRAMIA

Class Insecta •  most successful class most terrestrial,

capable of flight •  body regions: head, thorax & abdomen •  pair of antennae, several mouthparts,

3 pairs of walking legs + wings •  variations: mouthparts, body form, legs

Subphylum UNIRAMIA

•  respiration: spiracles opening into tracheae

•  excretion: malpighian tubules •  metamorphosis:

incomplete (e.g. grasshopper, cockroach)

egg nymph adult complete (e.g. butterfly, bee, fly, beetle)

egg larva pupa adult

Incomplete Metamorphosis

Complete Metamorphosis

And the famousest of them all…