12. Arthopods Flashcards
what are Arthopods?
segmented coelomates
exoskeleton
jointed appendages
what enviornment are they found in?
all enviornments - marine, freshwater, air
what phylum may they have derived from? why?
primitive annelids (segmented worms) or from ancestors common to both annelids and arthopods,
they share several features - both metameric (reptition of segments)
what is tagamatistaion?
the segments in arthopods - head, thorax and abdomen
what is an exoskeleton and why is it so important?
being able to secrete an outer layer of cuticle that is not damaged by water and gas. important for survival
what is the exoskeleton made out of?
a waxy layer of epicuticle. refer to image
what is the order of the exoskeleton from external to internal?
outer epicuticle
inner epicuticle
cement
wax
oriented wax
cuticulin
inner epicuticle
exocuticle
pore canal
how is the procuticle hardened? the process name
hardened via ‘tanning’ via a process called sclerotistion
how do arthopods move? how do they do this? (their body). how do their muscles work?
locomotion through they jointed foot. this is because the parts of the body where the cuticle is thin and flexible, joints form. joints opperate antagonastically (like humans)
how does an arthopod grow?
the exoskeleton cuticle cant grow, arthropods pierce it with sensory hairs and gland openings
what are the 6 steps of the shedding of the exoskeleton?
- pierced by sensory glands and gland openings
- enzymes secreted by the epidermis digest some of the exoskeleton
- cuticle is shed - includes front and hind parts, digestive system and gut lining
- old cuticle is split
- blood pressure increases causing swelling and growth
- new layer of cuticle is secreted
what was the shape of the body of the class trilobites?
flattened dorsoventrally and divited into three tagmata
what class were king crabs in?
malocostraca
who are king crabs most closely related too?
spiders
what class are mites and ticks within?
arachnids
