1.6 Invertebrates Flashcards
Know the difference between a vertebrate and invertebrate animal Describe the main characteristics of 4 invertebrate groups Distinguish between different classes of arthropods Understand the importance of metamorphosis in insects
all animals share one characteristic
feed on organic molecules
vertebrate
have backbone
invertebrate
no backbone
4 groups of invertebrates + examples
nematodes - hookworms
annelid - earthworms
mollusc - snails
arthropods
- crustacea - crabs
- myriapods - milipedes
- insects - flies
- arachnids - spiders
nematodes
parasites
mouth sucks blood long muscles wriggle long, thin body X washed out mucus resists stomach acid large sex organs - many sperm, eggs anus
annelids
long, segmented body
chaetae (bristles on segments for moving)
mouth - bite dead leaves
citellum - binds 2 tgt for sexual reproduction
cylindrical
mucus keeps moist
molluscs
hard shell, soft body, no limbs
shell - hardened by calcium carbonate body - can withdraw entirely into shell eye on tentacles mouthparts scrape at food foot - muscle + slimy covering for creeping
annelid vs nematode vs mollusc
body covering:
hard & slightly waterproof // soft, not waterproof // soft, shell saves water
visible segments:
yes // no // no
movement:
chaetae // wriggles but lives in one place // creeps around
feeding:
herbivores // parasites // most herbivores, some carnivores
arthropods
most numerous
insects, crustacea, arachnids, myriapods
crustacea
hard, serrated claw edge jointed limbs eyes carapace (thick, hard shell) Gill under shell
myriapods
antennae sense chemical & moisture in dark
segments help wriggle about
mouthparts bite (milipedes - vegetation, centipedes - other animals)
hard exoskeleton
walking legs w joints, internal muscles
waterproof body covering
insects
metamorphosis
3 segments head thorax abdomen antennae sense chemicals specialized mouthparts for feeding compound eyes detect food & predators 3 pairs of legs @thorax 2 pairs of wings
metamorphosis
allows different stages w diff food sources, specialized for different things,..
arachnids
head + thorax = cephalothorax
simple eyes >1 pair
spinneret
powerful piercing jaws
