LAB 2

Question 1

what makes up phylum platyhelminthes

Answer 1

flatworms with 4 classes: turbellaria (mostly free living), monogena, trematoda and cestoda (al parasitic)

Question 2

key features of platyhelminthes

Answer 2

triploblasts, cephalisation, CNS, excretion systems, bilateral and dorso-ventrally flattened, acoelomate

Question 3

where are platyhelminthes found

Answer 3

widespread and found in terresrial, marine and freshwater habitats

Question 4

what layer provieds compression to the hydrostatic skeleton in platyhelminthes

Answer 4

ciliated ventral epidermis or the mesenchymal tissues

Question 5

how do platyhelminthes reproduce

Answer 5

sexual with the exchange of sperm. the fertilised eggs are the released and usually develop directly into flatworms

Question 6

what kind of larvae to platyhelminthes have

Answer 6

muller’s larvae

Question 7

how do free-living platyhelminthes move?

Answer 7

by a ciliated ventral surface

Question 8

are platyhelminthes cephalised?

Answer 8

they are cephalised with a simple cns and lateral nerve cords and a nerve ladder

Question 9

nematodes are freeliving and parasitic true or false

Answer 9

true

Question 10

key features of nematodes

Answer 10

ubiquitous, triploblastic, unsegmented, well developed cuticle, no circular muscles, longitudinal muscles, unique excretory cells called Renette cells

Question 11

nematodes are blastocoelomates true or false

Answer 11

true.

Question 12

nematodes are gonochoristic true or false

Answer 12

true

Question 13

what are nemertea

Answer 13

ribbon worms and arrow worms

Question 14

key features of nemertea

Answer 14

mostly marine, mostly predators, triploblastic, bilateral, unsegmented, through gut, circulatory system, unique proboscis

Question 15

what is a proboscis

Answer 15

an extendable feeding aparatus housed in the rhynchocoel. it is extended by hydrostatic pressure for capturing prey

Question 16

what are proboscis armed with

Answer 16

piercing and toxic stylets for killing prey

Question 17

what nemertean features indicate cephalisation?

Answer 17

centralisation of nerves and feeding utensils at one end of the body (CNS)

Question 18

nemertea digestive track is complete with a mouth and anus true or false

Answer 18

true

Question 19

how many muscle layers do nemertea have

Answer 19

2 to 3 layers

Question 20

nemertea have an open circulatory system true or false

Answer 20

false - closed with some haemoglobin, diffusion of gases across body wall

Question 21

what type of larvae do nemertea have

Answer 21

pilidium larvae