Biology 11- Arthropods

Response of Crustaceans

• Well-developed nervous system 

• Brain which consists of a pair of ganglia  

• Ventral neve cord connects the brain with the rest of the body 

• Simple sense organs (statocysts) and chemical receptors 

• Compound eye 

feeding

• Every mode of feeding and there is a great variation  

• Locusts: herbivores and will eat anything green 

• Carnivores like spiders, preying mantic, centipedes, eat other animals 

• Crabs and crayfish eat already dead animals 

• Parasitic ones may be external or internal (ticks, flea, lice) 

• Some area also filter feeders 

respiration

• Gills 

• Book gills and book lungs 

• Tracheal tubes 

internal transport system

• Well-developed heart pumps blood through an open circulatory system 

• Blood moves through spaces in the tissues called sinuses 

• Blood collects in a large cavity surrounding the heart, then re-enters the heart through small opening  

movement

• Well-developed muscle systems coordinated by the nervous system 

• Pull of muscles against the exo skeleton allows arthropods to beat their wings, walk, or swim 

excretion

• Undigested food becomes solid waste and leaves through anus 

• Nitrogen-containing waste from cellular metabolism are removed in different ways 

  • Terrestrial arthropods use Malpighian tubules which removes waste from body sinuses, concentrate them, and add them to undigested food before it leaves the anus 

  • Some may have excretory glands at the bases of their legs, instead of Malpighian tubules 

  • Aquatic arthropods eliminate it through their heads (green glands) 

Reproduction

• Male produce sperm, female produce eggs 

• Fertilization takes place inside 

Body plan

jointed appendages, segmented bodies, exoskeleton

ecological roles of other arthropods

• Pollination 

• Production of honey, wax, silk 

• Recycle biological material to air in producing topsoil 

• Fomr symbiotic relationship with other organisms 

• Part of the food chain 

3 main features of arthropods

tough exoskeleton, jointed appendages, segmented body

body plan of arthropods

external supporting structures made of chitin

Label

swimmerets

creates water currents, which bring oxygen to their gills and propels them backwards

uropod

used for swimming, steering, tail flipping 

 

maxillipeds

mouth appendages that hold and bring food to the mouth 

cheliped

defend itself and snare prey

antennae

tactile or touch receptors to gather information

green gland

excretion of liquid waste

carapace

large bumpy covering over the thorax used for protection 

mandible

sturdy jaws around the mouth used for chewing

gastric mill

second set of internal "teeth" used to grind food in stomach

3 subphyla of arthropoda

Uniramia- centipedes, millipeds, all insects
Chelicerate- spiders, ticks, scorpians
crustacea- lobsters, crabs