Lecture 10 Flashcards
major arthropod lineages
chelicerata (subphylum) / merostomata (class)
arachnida (class)
why do curstaceans and insects ‘rule’ their respective habitata
describe variation in arthropod paired appendages
describe respiratory and excretory system in insects
subphylum trilobitomorpha
dominant during cambrian period, extinct now
flattened body with three tagmata (head, thorax and pygidium)
Biramous appendanges (two parts)
subphylum chelicerata
spiders, mites, ticks and horseshoe crabs
first land animals
first paired appendages = chelicerae
second paired appendages = pedipalps
two tagmata: prosoma and opisthosoma
no antennae
limulus
class: Merostomata
phylum: arthropods
subphylum: chelicerata
most forms are extinct
arachnida
spiders, mites, ticks, scorpions and harvesters
excretion via coxal glands or malpighian tubules
book lungs or trachea
dioecious
direct development (no larvae)
eleborate courtship rituals in some spp
subphylum Myriopoda, e.g…..
myriad = ten thousand
podos = foot
primitive body plan
two tagmata ) head and trunk)
one or two pairs of legs per body segment
millipedes:
- x section, two pairs of appendages/body seg
centipedes:
- depressed, one pair of appendages/ body seg
crustaceans
not a valid taxonomic group (paraphyletic)
aquatic
antennae always in two pairs
biramous appendages
three classes:
- malacostraca
- copepoda
- branchiopoda
class malacostraca
shrimps, lobsters, crabs, isopods, amphipods
two body regions
- cephalothorax (sensory and feeding tagmata fused with locomotory tagmata)
- abdomen (visceral and locomotor function
economically and ecologically important
malacostraca appendages:
Antennae (2 pairs)
Mouth:
mandibles
maxillae (2 pairs)
maxillipeds (3 pairs)
abdomen:
pereopods (5 pairs)
tail:
pleopods (5 pairs)
uropod
class copepoda
cylindrical body and median ocellus (eye spot)
first atennae modified for swimming (enlarged)
dominant in northern oceans
critical for food webs
branchiopoda
branchio = gill
podos = foot
fairy shrimps, brine shrimps, water fleas
mostly freshwater
leaflike respiratory appendages
some seasonally parthenogenic (development from unfertalized eggs, asexual)
subphylum Hexapoda
three tagmata: head thorax abdomen
five pairs of appendages on head antennae and mouth parts)
three pairs of appendages on thorax + one or two pairs of wings
class insecta
Huge diversity
one pair of antennae
gas exchange via trachea system; malpighain tubules (excretion)
30 orders, characterized by mouth part
enormous ecological importance
insect mouthparts variation
chewing, piercing-sucking, siphoning and sponging
arthropod tracheal system
gas exchange
series of tubules extended from exoskeleton
can regulate using muscle contractions
arthropod excretion/digestive system
active transport: NaK, uric acid (in Malpighian tubule), NA/K/sugars/amino acids (in rectum)
passive transport/movement: water/sugars/amino aicds )in malpighian tubule), water (in rectum)
Defecation: uric acid
