chapter 31: arthropods
DESCRIPTION
Chapter 31: Arthropods. Examples: insects, crustaceans, arachnids, centipedes, millipedes. Most diverse phylum. Features of Arthropods. “Jointed” appendages Segmented body: head, thorax, abdomen, cephalothoraxes – fused head and thorax – (arachnids). Eyes of Arthropods. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 31: Arthropods
Examples: insects, crustaceans, arachnids, centipedes, millipedes
Most diverse phylum
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
Exoskeleton
Made of chitinPurpose:
Molting – shedding exoskeleton
Respiration
Varies from group to group.Examples: trachea with spiraclesGills (aquatic)Book lungs (arachnids)
Open Circulatory System
Excretory System
Malpighian tubules – sort of like our kidneys. Structures that filter blood.
I. Arachnids-unique characteristics
Examples: spiders, scorpions, ticks, daddy long legsEight legs2 body segments: cephalothorax, abdomenChelicerae – fangsBreath by using book lungs or tracheal tubes
Unique Feeding of Spiders
Spiders can biteAll have venom Spin web for capture
Brown Recluse
Brown Recluse
Wolf Spider
Tarantula
Camel spider
Scorpions
Poisonous Stinger, Nocturnal
Household Dust mite
II. Insects
Largest group on earth3 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
Pupa stage with chrysalis
Adult stage
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
Head Lice
III. Crustaceans
Examples: crayfish, lobsters, pill bugs, crabs, barnaclesUse gills
IV: Millipedes and centipedes
-1 Pair of legs per segment
-Painful bite
-2 pair of legs per segment
-Herbivores
Ch. 32 Echinoderms
Features of Echinoderms
Spiny, marine invertebratesEndoskeleton – purpose is for protection, muscle attachment– Ossicles with spines
Begin as bilateral, free-swimming larvae
Features of Echinoderms
Radial symmetry as an adult
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
Ventral surface of sea star
Additional Characteristics
Nervous system: ring of nerves, eyespotsAbility to regenerateDiet – hetertrophs: corals, worms, mollusksSome are herbivores
Wrap up
Echinoderms
Seastars Brittle stars Sea urchins Feather Stars
Group 1: Sea Stars
Brittle Stars
Highly flexible arms, no anus, also feet on detritus – bottom dweller, regeneration
Feather Stars
Not sessile, but like to be, sticky arms, nocturnal
Sea Cucumbers
Regeneration of organs, tube feet
Sea Urchins
Scrape algae off of rocks, sponges, tube feet