Phylum Arthropoda
• animals with jointed legs
chitinous exoskeleton (hard) & jointed appendages
body covered with a
Chitin
is a major component of the exoskleleton of insects helping them in protecting their delicate soft tissue
Ventral nerve cord
nervous system of arthropods
True segmentation
segmentation
bilateral
symmetry
open
circulatory system
Head, thorax, abdomen
tagmata of arthropods
Exoskeleton
covers the entire arthropod body; tough • thin & flexible
articular membrane
exoskeleton are divided into sections, connected by
joint
enables arthropods to move
Molting
à periodic shedding of exoskeleton
Telson
growth results from addition of new segments to the region immediately anterior to the terminal section of the body called
SP Trilobita
• fossil marine arthropods • all extinct now • 200 million years ago • one pair of antennae • biramous appendages
Chelicerae
1st pair of appendeges
SP Chelicerata
have chelicerae, • no antennae, no mandibles • simple eyes • 4 pairs of walking legs • 1 pair of pedipalps
Pedipalps
for feeding and reproduction of Chelicerata
Class Merostomata
fossils dates back to Triassic (245 million years ago) • with carapace & telson
Limulus
example of class merostomata
Class Arachnida
spiders, scorpions, ticks, mites § mostly free-living & are far more common in warm, dry regions
Cephalothorax, abdomen
2 body segments of class arachnida
Order Acari
fused segments § parasitic (blood suckers) – vertebrates, invertebrates, plants
SP Crustacea
defining characteristic: the only arthropods with two pairs of antennae
SP Crustacea
• marine & freshwater • most with carapace • biramous appendage (2 branches, two pairs of antenna
oar footed
remipedes means
Class Remipedia
living in caves that have connections with the sea • no carapace, eyes & pigmentation • have large cephalic appendages (head) • swimming appendages laterally present on each segment • animals swim on their back; generally slow-moving
Class Cephalocarida
horseshoe shrimp • no carapace; lack compound eyes (muddy habitat) • abdominal appendages • uniramous antennule • biramous antennae
Class Branchiopoda
•water fleas, brine shrimp, fairy shrimp)• carapace: absent or present • no maxillipeds • antennules reduced • with compound eyes • capable of parthenogenesis (growing from unfertilized eggs) • feeding: suspension feeding, scraping
Class Maxillopoda
• 5 cephalic segments • 6 thoracic segments • 4 abdominal segments • telson • no abdominal appendages
Class Malacostrata
• ~3/4 of known crustaceans • include the largest crustacean
Order Decapoda
crabs, lobsters, prawns, shrimps § commercially important
5
how many walking legs does Decapoda have
3
how many maxilliped does Decapoda have
Chelae
the 1st pair of walking legs is modified into what in decapods?
Class Cirripedia
• barnacles, ~1000 species • attached to hard substrates • suspension feeders • live enclosed in calcareous plates • all marine
Class Copepoda
have thorax with 6 segments • 1st thorax segment is fused to the head • have single median eye
SP Myriapoda
many legs • head has a pair of antennae • 3 pairs of appendages modified as mouthparts, including jaw-like mandibles
Class Diplopoda
each trunk segment has 2 pairs of legs § feed on decaying leaves & other plant matter
Millipedes
example of class diplopoda
Class Chilopoda
each trunk segment has 1 pair of legs § carnivores
Centipedes
examples of Class Chilopoda
SP Hexapoda Class Insecta
most diverse & abundant group § body has 3 regions: head, thorax with 2 pairs of wings, abdomen with 3 pairs of legs
cerebral ganglion & nerve cords
nervous system of Class Insecta
Antennae, concentrated in the head
sensory organs of CLass insecta
open
circulatory system of Hexapoda
Spiracle
respiration: tracheal tubes open to the outside body through the
Tracheal tubes towards spiracle
allow 02 to enter & diffuse directly to cells
Malpighian tubes
in excretory sytem, this remove metabolic wastes from hemolyp
Flying
key to great success of this group
Holometabolous
complete metamorphosis
Hemimetabolous
Incomplete metamorphosis
Tent caterpillar
Pest of many trees and shrubs
Boll Weevil
Destroys cotton
Mosquitos
Vector (Malaria, Yellow fever, Encephalitis, West Nile virus)
FLea
Vector for Plague
Lady bug
Eats harmful insects
Silkworm moth
Lava produces silk Breakdown dung
Honey bee
Honey Pollinates crops