zool 5.3

• animals with jointed legs

body covered with a

is a major component of the exoskleleton of insects helping them in protecting their delicate soft tissue

nervous system of arthropods

segmentation

symmetry

circulatory system

tagmata of arthropods

covers the entire arthropod body; tough • thin & flexible

exoskeleton are divided into sections, connected by

enables arthropods to move

à periodic shedding of exoskeleton

growth results from addition of new segments to the region immediately anterior to the terminal section of the body called

• fossil marine arthropods • all extinct now • 200 million years ago • one pair of antennae • biramous appendages

1st pair of appendeges

have chelicerae, • no antennae, no mandibles • simple eyes • 4 pairs of walking legs • 1 pair of pedipalps

for feeding and reproduction of Chelicerata

fossils dates back to Triassic (245 million years ago) • with carapace & telson

example of class merostomata

spiders, scorpions, ticks, mites § mostly free-living & are far more common in warm, dry regions

2 body segments of class arachnida

fused segments § parasitic (blood suckers) – vertebrates, invertebrates, plants

defining characteristic: the only arthropods with two pairs of antennae

• marine & freshwater • most with carapace • biramous appendage (2 branches, two pairs of antenna

remipedes means

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

horseshoe shrimp • no carapace; lack compound eyes (muddy habitat) • abdominal appendages • uniramous antennule • biramous antennae

•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

• 5 cephalic segments • 6 thoracic segments • 4 abdominal segments • telson • no abdominal appendages

• ~3/4 of known crustaceans • include the largest crustacean

crabs, lobsters, prawns, shrimps § commercially important

how many walking legs does Decapoda have

how many maxilliped does Decapoda have

the 1st pair of walking legs is modified into what in decapods?

• barnacles, ~1000 species • attached to hard substrates • suspension feeders • live enclosed in calcareous plates • all marine

have thorax with 6 segments • 1st thorax segment is fused to the head • have single median eye

many legs • head has a pair of antennae • 3 pairs of appendages modified as mouthparts, including jaw-like mandibles

each trunk segment has 2 pairs of legs § feed on decaying leaves & other plant matter

example of class diplopoda

each trunk segment has 1 pair of legs § carnivores

examples of Class Chilopoda

most diverse & abundant group § body has 3 regions: head, thorax with 2 pairs of wings, abdomen with 3 pairs of legs

nervous system of Class Insecta

sensory organs of CLass insecta

circulatory system of Hexapoda

respiration: tracheal tubes open to the outside body through the

allow 02 to enter & diffuse directly to cells

in excretory sytem, this remove metabolic wastes from hemolyp

key to great success of this group

complete metamorphosis

Incomplete metamorphosis

Pest of many trees and shrubs

Destroys cotton

Vector (Malaria, Yellow fever, Encephalitis, West Nile virus)

Vector for Plague

Eats harmful insects

Lava produces silk Breakdown dung

Honey Pollinates crops