Dr. Kathy S. Williams (email firstname.lastname@example.org)
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The large group of segmented animals with exoskeletons is known collectively as the arthropods and includes the most diverse of
all animals. (614-624) * FIG. 48.13 Animal clade
Understand the evolution of arthropods by studying their ancestors & relatives. (615-617)
u There are 2 groups intermediate
between annelids & arthropods: Onychophorans & Tardigrades
* Figures of an onychophoran & a tardigrade
Development of an exoskeleton was a major evolutionary change in animal body form. (1012)
u includes jointed appendages
u has limitations What are the advantages / disadvantages of an exoskeleton?
Most of all living arthropods are classified into one of three major
Uniramia (myriapods & insects). (617-624)
(compare and contrast with protonephridia & metanephridia)
ARTHROPOD DIVERSITY: Chelicerata & Crustacea
Most living arthropods (crabs, lobsters, scorpions, spiders, insects) - classified into one of 3 major taxa: Chelicerata, Crustacea, & Uniramia.
Chelicerata includes Merostomata (horseshoe crabs), & Arachnida (spiders, scorpions, mites, & relatives) (617-618)
Merostomata (horseshoe crabs) is a "living fossil"
u respiratory surfaces
u respiratory surfaces *
FIG. Book lungs CLICK
HERE FOR BOOK LUNG OVERHEAD
CLICK HERE FOR CRUSTACEA OVERHEAD
• also barnacles & pillbugs
Uniramia are closely related to Crustacea.
u 3-part brain * FIG. 3-part brain
Notable myriapods are the millipedes & centipedes. * FIG. 33.31 Myriapods
u Chilapoda are active predators & have poisonous fangs.
u Diplopoda are scavengers,
without fangs. What does the word ‘diplopod’ signify?
u wings, on most adults
u gas exchange system - spiracles & tracheae (828-830, * FIG. 42.21 Tracheae)
u excretory organs - malpighian tubules (881, * FIG. 44.17 Malpighian tubules)
u development & metamorphosis (* FIG. 33.34 Insect metamorphosis)