Ch 8: Platyhelminthes Flashcards
all bilateral animals are ? blastic
triplo
how did the need for cephalization and centralization arise?
- evolved when radial animals began moving along a surface to inc probability of finding food
- anterior end adapted to sense the oncoming env
bilateral guts
- usually a complete tube
- foregut and hindgut developfrom ectoderm
- midgut from endoderm
do all bilateral animals have an excretory system?
almost, yes, except the teeny tiny ones
are most bilateral animals proto or deuterostomes?
protostomes
5 characteristics of platyhelminthes
- bilateral
- dorso-ventrally flattened
- triploblastic but acoelomate
- digestive system is a gv cavity
- no separate circ system
2 features that help make platys good endoparasites
- small size, small eaters
- flat; can live in tight spaces
are turbellaria free-living or parasites?
free-living
trematoda/flukes are endoparasites with ? hosts
several
monogenea are ectoparasites with? hosts
1
cestoda/tapeworms are endoparasites with ? hosts
1-2
how do Turbellaria move?
use cilia, muscular creeping, swimming, slime for locomotion
what do the epidermal glands in Turbellaria prod and why?
abundant mucus for locomotion, and perhaps as predator repellant
a variety of other glands in Turb prod other substances like
adhesive substances
what is Turbs epidermus like?
ciliated, mono-layered
6 features of Turbs
- mostly free-living
- mostly bottom dwellers
- extendable pharynx usually near middle of ventral side
- relatively well-developed head and sense organs
- a true CNS and a “brain”
- 2 interconnected ventral nerve cords
what do Turbs eat?
bacteria, single celled algae, small animals, corals
how is prey captured? (5)
- by wrapping around it
- entangling in mucus
- pinning down with adhesive glands
- stabbing with penis
- secreting enzymes
how is food swallowed?
whole, or in pieces via muscular waves of pharynx