Midterm II (Non-arthropod ecdysozoa) Flashcards
1
Q
Phylum Nematoda
A
- “thread”; roundworms; <5 cm
- around 30,000-1 000 000 spp!
- V. abundant all over world; high human impact
solid/oceans/FW/polar/mountains/plants/animals - Most important of all parasitic animal groups
- Ecto- and endoparasites: plants and animals; crops
- Adapted mouth parts (hooks, etc.)
- Reproduction (100 000s of eggs)
2
Q
Nematoda morphology
A
- Thick cuticles (collagen) = defense and support
- Fluid-filled pseudocoelom functions as a hydrostatic skeleton
- No circular muscles (4 quadrants extend to pseudocoelem; antagonistic muscle support from cuticle)
- Thrashing motion in water, more controlled in soil
3
Q
Examples of common nematode parasites
A
- Intestinal Roundworm (Ascaris)
- up to 1 billion people infected! - Hookworm (blood suckers)
- around 650 million people infected - Pinworms
- don’t need an intermediate host
- most common nematode parasite of developed countries - Filarial worms
- arthropod transmission
- around 200 million people infected
4
Q
Caenorhabditis elegans
A
- free-living, non-hazardous/infectious/pathogenic/parasitic
- around 1mm; lives in soil/rotting vegetation; feeds on bacteria and yeast
- One of most important experimental biological models
- All 959 cells traced from zygote to adult
- Entire nervous system known
- Genome entirely mapped and all 19 820 genes sequenced
5
Q
Phylum Nematomorpha
A
- “thread + form”; horsehair worms
- up to 1 m long!
- around 320 species; live in wet/moist areas
- Pseudocoelomates
- Semi-parasitic (via eating/drinking water)
- adults free-living
- parasitic in arthropods as juveniles
- Paragodius obamai: parthenogenetic
- Intermediate (halted) and definitive host for development; bit free-living reproduction
- Encysts on vegetation or in intermediate host
6
Q
Parnarthropoda -> Phylum Onychophora
A
- “claw + to bear”; velvet worms
- around 200 species
- 500 million yr history in fossil record. originally marine
- Tropical and subtropical leafy habitats (high moisture)
- Caterpillar-like; 0.5-15 cm
- Mostly predators (insects/snails/worms) w slime
- Soft cuticle - repels water (“velvet”)
- 14-43 pairs of unjointed legs w pad and 2 claws
7
Q
Panarthropoda -> Phylum Tardigrada
A
- “slow + step”; moss piglets, water bears!
- Marine, freshwater, damp terrestrial (mosses, lichens)
- around 1150 species; < 1 mm
- 8 unjointed legs w claws
- Pair of sharp stylets (some) and sucking pharynx
- piercing and sucking plant juices or other small invertabrates
- Parthenogenetic or sexual
- Cryptobiosis!!