lecture 5 Invertebrates (non-arthropods): nematodes & echinoderms

Question 1

what does the phylum nematoda mean in latin

Answer 1

nemato = threadlike

Question 2

what kind of symmetry do nematodes have

Answer 2

bilateral symmetry

Question 3

what kind of bodies do nematodes have

Answer 3

cylindrical bodies with tapering ends

tubular, with mouth at head end starts the complete gut

Question 4

what kind of coelomates are nematodes

Answer 4

pseudocoelomates

internal cavity but internal organs not surrounded by a mesoderm

Question 5

what type of cuticle do nematodes have and how does this aid them

Answer 5

multi layered cubicle helps maintain high pressure inside (hydrostatic skelton)

Question 6

what are the two life styles of nematodes

Answer 6

free living and parasites

Question 7

where do free living nematodes live

Answer 7

found in all habitats

90% of animals on seabed, 80% of all individual animals

Question 8

what do free living nematodes eat

Answer 8

in soil most eat bacteria and fungi(most species are microscopic)
some eat crops such as potato cyst nematodes

Question 9

examples of parasitic nematodes

Answer 9

ascariasis
guinea worms
pinworms

Question 10

what is elephantiasis

Answer 10

caused by infection with filariasis type nematodes

infects lymphatic system and causes swelling

Question 11

what are the human stages in filariasis

Answer 11

mosquito takes a bite l3 larvae enters skin

adults in lymphatics produce sheathed microfilarae that migrate into lymph and blood channels

Question 12

what are the mosquito stages in filariasis

Answer 12

mosquito takes a blood meal and ingest microfilariae
microfilariae shed sheaths penetrate mosquitos mid gut and migrate into thoracic muscles
l1 l3 larvae
migrate to head
mosquito takes a meal

Question 13

what kind of sexual reproduction do nematodes have

Answer 13

separate sexes with sexual reproduction (internal fertilisation)

Question 14

why is caenorhabditis elegans an important model for cell and developmental biology

Answer 14

first multicelular organism to have its genome sequenced

very rare case of androdioecous species

Question 15

what does androdioecous mean

Answer 15

most are hermaphrodies but when stressed males exist (rare)

Question 16

what does the phylum name echinodermata mean

Answer 16

echin = spiny
derma = skin

Question 17

what are some included echinoderms

Answer 17

sea lilies
sea urchins
starfish
sea cucumbers

Question 18

what kind of symmetry do echinoderms have

Answer 18

bilateral in larvae

5 fold radial symmetry in adults

Question 19

what kind of coelomates are echinoderms

Answer 19

coelomates

Question 20

what does pentatomerous

Answer 20

radial body symmetry with five sides

Question 21

what does the water-vascular system consist of

Answer 21

internal canals and external tube feet

Question 22

what are the calcareous plates and spines

Answer 22

epidermis covering an endoskeleton

Question 23

how do echinoderms reproduce

Answer 23

sexual reproduction with seperate sexes

Question 24

what does the class crinoidea mean in latin

Answer 24

crino = lily

sea lilies and feather stars

Question 25

what does the class asteroidea mean in latin

Answer 25

astero = star

starfish

Question 26

what does the class ophiuroidea mean in latin

Answer 26

ophiuro = snake tail

brittle star

Question 27

what does the class echinoidea mean in latin

Answer 27

echino = porcupine, hedgehog

seaa urchins and sand dollars

Question 28

what does the class holothuroidea mean in latin

Answer 28

holothuro = kind of water polyp

Question 29

what is special about nematodes external coat

Answer 29

it is thick and needs to be shed to grow