12 Phylum Arthropoda Flashcards
The most species-diverse phylum in the animal kingdom
(3/4th of all known species)
* Utilize all modes of feeding: carnivory, herbivory, omnivory,
and some parasitic
* Most widely distributed in all kinds of habitats, some
surviving in places where no other animal could survive
* Mainly characterized by having segmented bodies, and
having legs and appendages that are jointed
* Bilateral symmetry
* Triploblastic body
* Eucoelomate body cavity
* Level of complexity: Organ-system grade
* Definite cephalization
Phylum ARTHROPODA
Segmented body is divided into functional groups called
tagmata
(arthron = “ ” + podos = “ ”)
joint, foot
The number of tagmatas depends on the subphylum:
Subphylum Myriapoda
Subphylum Hexapoda
Subphylum Crustacea
2 tagmatas: Head and Trunk
Subphylum Myriapoda
3 tagmatas: Heat, Thorax, and Abdomen
Subphylum Hexapoda
2 tagmatas: Cephalothorax (a fusion of head and
thorax) and Abdomen
Subphylum Crustacea
– a strong and highly protective covering that is also very flexible
Exoskeleton
makes up the hard exoskeleton. It is mainly composed of a protein called chitin and sometimes calcium carbonate
Cuticle
– the outer, thin layer that can harder to increase protective capability
Epicuticle
the inner, thick layer that is flexible. It is
further divided into 2 layers:
Procuticle
(secreted before molting)
Exocuticle
(secreted after molting)
Endocuticle
the process of shedding of the outer covering at
the cuticular exoskeleton as the arthropod grows.
Molting
The process of molting terminates at the actual
shedding of the old exoskeleton (called )
ecdysis
After molting, the arthropod has new but soft exoskeleton. In time, it will harden (the process of
hardening is called
schlerotization)
abundant inside hollow limbs for rapid movement
Striated
found in the organs (like in digestive system.
Smooth
– has a long, straw-like proboscis to suck liquid food (ex. Butterfly, mosquito, etc.)
Sucking type
– the tip of the proboscis contains grooves that sponges up liquid/semi-liquid food (ex. Housefly, bees, etc.)
Sponging/Lapping type
(lays eggs)
oviparous
– their mouthparts contain powerful, horizontally cutting mandibles/jaws to cut
solid food (ex. Beetles, grasshopper, spiders, crabs, cockroaches, etc.)
Chewing type
(lays eggs inside body and
births larva/young)
ovoviviparous
(gives birth directly to
larva/young)
viviparous
Many arthropods pass through metamorphic changes, including a larval form that is morphologically
different from the adult
metamorphic changes
(the “blood” of
arthropods)
hemolymph
– type of excretory and
osmoregulatory system consisting of branching tubules extending from the alimentary canal.
Malpighian tubule system
The respiratory system of most insects; it consists of cuticle-lined air tubes
that branches throughout the body and open in tine holes in the abdomen called spiracles.
Tracheal system
a series of highly vascular plates (that are arranged like pages of a book) that
serves as respiratory system in arachnids (spiders, scorpions, etc) and crustaceans (crabs,
lobsters, etc.)
book lungs
– the “blood” of most arthropods, which is white and fatty
Hemolymph / Hemocoel
(not enclosed in vessels and are found throughout the body cavity)
Open circulatory system
