Invertebrates Flashcards
Tagmosis
Differentiation of segments (head, thorax, abdomen)
Harmocoel
Open circulatory system
Heart
Dorsal
Pericardium - membrane enclosing
Nerve cord
Ventral
Biramous legs
2 branches
Uniramous legs
Single branch
What genes affect segment identity
Hox genes
Panarthropoda/Lobopoda
Tardigrada
Onychophora
Arthropoda
Onychophorans
Velvet worms
Terrestrial with soft cuticle
Telescopic claws
Oral papillae that secrete slime for predation and mandibles
Tardigrades
Water bears
Marine and terrestrial (extreme environments)
4 pairs of claw bearing legs
Triradiate pharynx (Y)
Fixed no of adult cells
Desiccation
Extreme drying
Mandibulata
Myriapods
Crustaceans
Insects (Hexapoda)
Have mandibles/jaws
Myriapods
Millipedes (Diplopoda)
Centipedes (Chilopoda)
Chilopoda
Centipedes
2 pairs of maxillae (2nd pair enlarged)
Poison glands on specialised limbs (1st trunk segment)
Predators - strong powerful legs
Aposematism
Aposematic colouring
Advertise venom/poison with bright colours
Diplopoda
Millipedes
Fused segments - 2 limbs per segment
Not single segments ^
Reduced number of mouthparts
Herbivores/detritivores
Crustaceans
Malacostraca
Maxillopoda
Branchiopoda
Xenocaridia
2 pairs of antennae
Biramous limbs
Nauplius larvae
Uropods
Tail flaps
Malacostraca
Decapoda
Pericardia
Euphausiacea
Stromatopoda
Phyllocardia
Head - 5 segments
Thorax - 8 segments
Abdomen - 6 segments
Stomatopoda
Mantis shrimp
Burrowing
Raptorial appendages - clubbing/piercing
Eyes - more than 16 pigments and polarised light
Decapoda
Crabs (Brachyurans + Anomurans)
Lobsters - larger claws
Shrimp - swimming limbs
3 most anterior thoracic segments - maxillipeds - food manipulation
Peracaridia
Mysids - shrimp like filter feeders
Amphipods (laterally compressed)
Isopods
Characterised by presence of marsupium - breeding pouch
Euphausiacea
Krill
important primary consumer
Maxillopoda
Theocostraca
Ostracoda
Pentastomida
fewer than 10 segments
next biggest group after Malacostraca
Theocostraca
Barnacles
Acorn + gooseneck
Ostracoda
Marine + fresh
calcareous shell
Pentastomidia
Parasitic crustaceans
Branchiopoda
Notostraca
Spinicaudata
Laevicaudata
Anostraca
Cladocera
Freshwater crustaceans
some developed bivalved carapace
Xenocardia
Cephalocarida
Remipedia
Chelicerata
Pycnogonids
Xiphosura
Mites and Ticks
Arachnida - spiders/scorpions/camel spiders/pseudo scorpions
Anatomy -
Prosoma
Tagmata of chelicerata
tagmosis of 6 embryonic segments
May have carapace
appendages:
no antennae or true mandibles
1 pair of chelicerae
pincers/fangs
1 pair of pedipalps - usually sensory (pincers)
4 pairs of walking legs
Opisthosoma
Tagmata of chelicerata
tagmosis of up to 12 embryonic segments + post-anal telson
May be undivided (spiders)
segmented (scorpions)
Appendages:
Book gills (Horseshoe crabs) - locomotion and respiration
Book lungs
Spinnerets (spiders) - silk manipulation
Chelicerae
Jointed feeding/mouthparts
Pycnogonids
Sea spiders
Marine
V long legs
commensals/ectoparasites of inverts
Small body - digestive system runs into legs
Xiphosura
Horseshoe crab
4 species
Large carapace protect prosoma
opisthosoma is fused
Scorpiones
Scorpions
arachnid
venomous telson
Tropical/sub-tropical/warm temperate environments
Araneae
Spiders
disparate ecologies
Spin silk
Take down prey using venom
sperm transfer with pedipalps
Book lung
Spinnerets - spools and spiggots
eyes:
8 in 4 pairs
main
secondary eyes - reflective tapetum lucidium - good in low light
Which spiders have image forming eyes
Jumping spiders and wolf spiders
Other arachnids (not spiders or scorpions)
Microwhip scorpions
Pseudo scorpions
Camel spider
Opiliones - harvestman/daddy long legs
Mites/ticks
Whip spider
Whip scorpion
Features of Insecta
Head/thorax/abdomen
3 pairs of legs
No appendages on abdomen
adults have 2 pairs of wings on thorax (usually)
compound eyes
ocelli - single lens to collect + focus light
Hexapod exoskeleton
Chitin rods in protein matrix
Spiral layering of chitin rods
‘Tanning’ of protein to Sclerotin
Waxy layer for waterproofing
Resilin - elastic protein
Apterygota
Wingless insects
silverfish
ants
lice + fleas
Apomorphy
New evolutionary development
Not homologous with existing…..
Insect wing
Forewing + hindwing
Apomorphy
More derived wings - more hinges for folding wings back
More derived wings - less wing veins
Beetle wings
forewing sclerotized
hardened cover - elytra
flightless beetles - elytra fused
Dipteran fly wings
hindwing reduced to haltere for balance during flight
Insects with 2 pairs of wings
Dragonfly - overlapping wings
Bees - wings hook together
Damselflies - out of phase
direct wing movement
Direct acting muscle (DAM) - basilar muscle contracts - directly pulls wing downward
Notum pushed upward
found in less derived insects - dragonflys (use indirect for raising)
Notum
top of thorax
indirect wing movement
To raise - indirect dorsoventral muscle contracts - notum pulled down - wings pulled upward due to mechanism of hinge
To lower - longitudinal muscles, in thorax contract - notum arch + lifted up - hinge of wing pops up forcing wing downward
Dipterian flies use indirect for both
Much higher flapping freq with indirect muscles
Tracheal system of Insects
Air piped through tubes - direct O2 delivery
Opens to outside via spiracles - one per segment of abdomen
open into atrium (small hairs + spines reduce dust + debris)
Feeding strategies of insects
Large variety of plants
maggots can feed on live flesh - myiasis
Feed on invert and vert - blood/tissue fluid in some species
large diversity of mouthparts - depends on diet (primitive for chewing) (evolved piercing + sucking parts)
Can feed on diff foods at diff stages of life - avoids comp between adult and young
Internal fertilisation in insects
Male passes spermatozoa in package - spermatophore
Female stores in organs called spermathecae until eggs mature
Releases sperm as eggs are being laid to fertilize
Reproductive diversity in insects
Viviparity - live larvae birthing (aphids)
Parthenogenic - young produced without mating (ants + aphids)
Parental care - ear wig + dung beetle supervise eggs
Colonial - one reproductive individual - social insects - colony is sterile (termites/ants/wasps/bees)
3 types of insect life cycle
Ametabolous
Hemimetabolous
Holometabolous
Ametabolous life cycle
found in wingless silverfish
No metamorphosis
simple development
juvenile looks like small adult
Hemimetabolous life cycle
juveniles similar to adults
Get bigger after each moult
Final moult - development of reproductive organs,/adult coloration/wings
wings are just wing pads in juveniles
Both live and eat the same
Holometabolous
full metamorphosis - most derived type
adult very different from larvae
larvae given different name - grub/maggot/caterpillar
Feed on different food
no antennae or compound eyes
mouthparts usually very different
wing pads not present
pupa stage - immobile and cryptic - gonads and wings develop
Biggest order - 10-1 outnumber
Mollusc anatomy
Foot
Mantle/mantle cavity
ctenidia
Radula
Shell + sclerites
tetraneurous nervous system
Mollusc foot
cilary locomotor organ
glide across soft + hard substrate - cilary beating + muscular undulations
modified into arms in cephalopods
burrowing organs in bivlaves + scaphopods
Mollusc mantle
Protecting covering surface
secretes shell and sclerites
gap between foot and mantle - mantle cavity - contains gills and other organs)
Mollusc ctenidia
gills/feeding in bivalves
Cilary beating - water current through lamellated structure
Many in chitons + monoplacophorms - reduced to 1/2 pairs in other forms
Mollusc radula
ventrally attached feeding organ
conveyer belt of teeth - replaced from posterior
Attached to tough proteinaceous odontophore - can be manipulated by muscles
Mollusc shell
CaCO3
structure varies - diff properties
nacre - mother of pearl
consist of several shell layers - organic periostracum + several underlying mineralised layers
secreted by mantle
Mollusc Nervous system
tetraneuros - 4 longitudinal nerves through body
pedal ganglion
visceral ganglion
circumoral nervering
Mollusc embryology
spiral cleavage
Trochophore larva
Mollusca
Aculifera
Conchifera
Aculifera
Polyplacophora
Aplacophora
Polyplacophora
Chitons
8 overlapping shell plates
Numerous ctenidia in mantle cavity
Radula enforced with magnetite
mantle has sclerites in arranged zones
Aplacophorans
Neomenimorpha
Chaetodermomorpha
shell less molluscs
Mantle has minute aragonite sclerites
Foot is reduced or absent
Neomenimorphs prey on hydroids
Chaetodermomorphs are infaunal selective detritovores
Conchifera
Monoplacophorans
Cephalopods
Gastropods
Bivalves
Scaphopods
Monoplacophorans
Serial gills
Have a number of muscle scars
similar to chitons
Scaphopods
Tusk shells
Tapering, tubular shells
infaunal burrowers
selective detritovores
