flatworms Flashcards
what are platyhelminthes
small, short bodied worms
what germ layer do flatworms have
tripoblastic 3 germ layer, causes organic system but with no coelum
why is size and volume limited in a flatworm
because they are dependant on diffusion for water and gas exchange
what type of symmetry do flatworms have
bilateral symmetry
how many species of flatworm are there
30 000
how many major classes and what are their names
4 major classes,
Turbellaria (5000sp), Trematoda (18 000sp), Monogenea (~6000sp), and Cestoda (6000sp)
how does the epidermis in flatworms range
from multinucleated cells to syncytial
how to most free moving flatworms move
by cilia beating in self-secreted mucus, and by muscular contractions
how does Turbellaria get their name
by the whirling motion of cilia in mucus
what does the very glandular epidermis secrete
specialised rhabdites (rod shaped), swell into mucous sheet in contact with water
what happens when the anterior secretory cells are aggrivated
production of ‘glue’ to stick to surfaces
how are flatworms bodies flattened
through the dorsoventral muscularate contracting and relaxing
roles of epidermal pigmentation in flatworms
uv protection, camouflage, conspecific ID, possible warning mimicry
what type of digestion system does flatworms have
incomplete, where the gut has numerous lateral branches
how is undigested material excreted
through the pharynx
what is the pharynx in flatworms
mid ventral, simple tube
how does excretion and osmoregulation occur in flatworms
through cutaneous diffusion and via specialised functional units called protonephridia
what are some types of asexual reproduction that flatworms do
fission and cloning
how do most flatworms reproduce
clonally at some point by dividing and regenerating missing parts from neoblasts
what is paratomy in flatworms
parent differentiates into chain of zooids before fission
what is architomy
differentiation after fission
what type of hemaphroditism does flatworms have
simultaneous, have both male and female parts at the same time
what is internal fertilisation in flatworms
where the male gametes is inserted, is the norm
what type of competitions do flatworms do to assume male role
penis fencing and hypodermic inpregnation
what are the 2 types of eggs that can be laid
summer eggs that have thinner capsules, and resting eggs that have thick capsules. can resist freezing, drying and stay dormant
