chapter 31: arthropods examples: insects, crustaceans, arachnids, centipedes, millipedes
TRANSCRIPT
Features of Arthropods
“Jointed” appendagesSegmented body: head, thorax, abdomen, cephalothoraxes – fused head and thorax – (arachnids)
Eyes of Arthropods
Compound eyes – eye with many units
Simple eyes – Single lens, see light and dark only, not image
Respiration
Varies from group to group.Examples: trachea with spiraclesGills (aquatic)Book lungs (arachnids)
I. Arachnids-unique characteristics
Examples: spiders, scorpions, ticks, daddy long legsEight legs2 body segments: cephalothorax, abdomenChelicerae – fangsBreath by using book lungs or tracheal tubes
II. Insects
Largest group on earth
3 Body sections:– Head – mouthparts,
antennae
– Thorax- 3 pairs of legs
– abdomen – spiracles- organs for breathing, open to tracheal tubes
Insect life cycle
Metamorphosis – physical changeTwo types – complete and incompleteComplete –– 1. Larva– 2. Chrysalis- cocoon– 3. Pupa – inside cocoons– 4. Adult
Incomplete Metamorphosis
Less of a change 1. Egg2. Nymph – a smaller
version of the adult with no wings
3. Adult
Success of Insects
Found everywhereShort life span, adapt to change quicklyFlight – Elaborate social systems
IV: Millipedes and centipedes
-1 Pair of legs per segment
-Painful bite
-2 pair of legs per segment
-Herbivores
Features of Echinoderms
Spiny, marine invertebratesEndoskeleton – purpose is for protection, muscle attachment– Ossicles with spines
Begin as bilateral, free-swimming larvae
Water Vascular System
System of canalsUsed for locomotion, feeding and gas exchangeWater flow through canals: – Madreporite– Ring canal– Radial canals– Tube feet – used for
locomotion
Additional Characteristics
Nervous system: ring of nerves, eyespotsAbility to regenerate
Diet – hetertrophs: corals, worms, mollusksSome are herbivores