Nematodes, Tardigrades and Onychphorans ECDYSOZOA

Question 1

What are ecdysozoa?

Answer 1

External cuticle, secreted by underlying epidermis.
Grow by shedding or moulting exoskeleton.
Evolved in cambrian period 500mya

Question 2

What are the four phyla of ecdysozoa

Answer 2

Nematoda - small, widespread, most individual animals, half parasites.
Tardigrada- Small, widespread in water, few species, herbivores.
Onychophora- damp forest, carnivores, few spp
Arthropoda- Crustacea, myriapoda, insecta, chelicerata.

Question 3

Nematoda, what are they?

Answer 3

REMEMBER: Ascaris, caenorhabditis.
roundworms
25,000 species probs 1 million
Free living in all habitats
Some parasitic - kidney worm

Question 4

What us the body of a nematoda like?

Answer 4

Psuedocoel
Complex cuticle covers body with 9 layers of collagen secreted by epiderms
Hydrostatic skeleton to make undulatory swimming movements
Through gut, sub terminal anus, faeces expelled with energy
Mouth has 3 lips

Question 5

What is special about ascaris?

Answer 5

It can squirt shit up to 60m

Question 6

What is the nervous system of a nematoda like?

Answer 6

Has a pharynegal nerve ring , 4 ganglia and 6 longitudinal nerves
UNIQUE muscle send processed into nervous system to make connections

Question 7

What is special about Caenorhabditis

Answer 7

Has hermaphrodite and male forms

Question 8

Caenorhabditis

Answer 8

Been to space
Egg to mature in 4 days,lives 4 weeks
1mm long
Model organism for biology of development

Question 9

What does ascaris cause?

Answer 9

River blindness

Question 10

What are Tardigrada

Answer 10

Almost everywhere damp
Minute
4 pairs of legs with claws
Haemocoel
Eutelic and cryptobiotic

Question 11

What are Onychophora

Answer 11

12-43 pairs of conical baggy legs
Cuticle thin protein and chitin
Squirt slime up to 4m to attack prey or defence