Bio Lab 3 Flashcards
phylum platyhelminthes
flatworms
phylum nematoda
round worms
Platyhelminthes and nematoda
- both are freshwater
- have a cellular mesoderm with an ectoderm and endoderm
- bilaterally symmetrical
acoelomate
mesoderm is a solid mass of tissue with no cavity and no cavity for internal organs
pseudocoelomates
have a body cavity called a pseudocoelom with a fluid space and a digestive tract
flatworms are
acoelomate
nematodes are
pseudocoelomates
coelomate
have major organs suspended in a coelomic cavity completely surrounded by mesoderm
triploblastic
have three embryological germ layers
flatworms and roundworms have germ layers…
triploblastic
flatworms and roundworms have ___ symmetry
bilateral symmetry with a distinct anterior and posterior end
draw the body plants for flatworms and roundworms
there is a diagram
Platyhelminthes
- have a gastrovascular cavity that is both mouth and anus (one opening)
- ladder like 2 spinal chords advanced nervous system
- are flat
- free living ones have ocelli called eyespots
- monoecious??
class turbellaria
are hemaphroditic (have both fem and male organs) and are scavengers
- have eyespots that can sense light
- have a ciliated ventral surface
- mouth and anus are at the end of pharynx with intestinal diverticuli
(Platyhelminthes)
species planaria (dugesia)
- free living
has sensory organs called eyespots and feed by sucking through a tubular pharynx that protrudes
class trematoda
- parasites (both end and ecto)
- called flukes
- lack an epidermis but have a epicuticle made of protein and lipids to stop digestion
- ventral surface has an oral sucker
- often require intermediate hosts to distribute
Platyhelminthes
species opisthorchis
from Trematoda
- found in fish and snails
- more clear inside
species fasciola
sucks blood (liver fluke)
- from trematoda
- uterus is near mouth, has a weird line through the middle
NOT LEECHES
species shistosoma
FROM TREMATODA (blood fluke) causes disease schistosomiasis - inhabits veins - is hermaphrodic THE FEMALE FITS INSIDE THE CAVITY TO LAY THE EGGs
intermediate host
harbours immature stages of parasite
definitive host
harbours mature parasite
class cestoda
Platyhelminthes
- anterior end called scolex, then neck then proglottids
- don’t have a gastrovascular cavity as nutrients come from host
- endoparasite
- mature packets called proglottids will detach and make larvae
NEMATODA
- very diverse
are slender with pseudocoelom and complete digestive tract - use hydrostatic pressure to move
- complete GI tract with a mouth an anus
- can be free living and parasitic
- cause disease in humans like elephantiasis
- don’t require multiple hosts to survive
species ascaris
nematoda
- have a hooked posterior end (anus)
- males are smaller
- to survive, they must pass through GI tract and have thick cuticle
how did these organisms evolve?
Syncytial Theory AND Colonial Theory:
Colonial Theory:
Evolved from flagellated protists; daughter cells failed to separate and were held together by an extracellular matrix. Evidenced by an extant colonial form of choanoflagellata (collared flagellates).
SYNCYTIAL theory
Evolved from a multinucleated, unicellular slim mold or ciliated protist; evidenced by insect embryology.
how evolved are they compared to others?
have three germ layers which is more evolved than cnidaria and porifera
- first group that has organs
SA to Volume ratio
as you get bigger, SA ratio gets smaller
- they are long and slender or thin and flat
- must have a metabolism
Platyhelminthes that are free living have eyespots called
ocelli
increased body size means
more surface area
- must be thing and plat. long and slender
diverticuli
inside the tubellaria, there are blind-ended branches in the gastrovascular cavity,
trichinella
causes trichinosis (Nematoda)
females of Trichinella live in the intestine of their host and release lar- vae. These larvae migrate through the body to striated muscles, The larvae remain encysted until the muscle tissue is eaten by another host, where the larvae mature. Humans infect themselves by eating pork
planaria movement
away from light due to eyespots
mature proglottid
contains ovaries and testes
gravid proglottid
contains eggs
do mature or gravid proglottids occur closest to the scolex?
mature
how do proglottis go in size as they near the end?
posterior end is larger
nematode movement
only have longitudinal muscles (no circular or diagonal ones) so it moves by flipping and end.
