Criteria
Nematoda
Platyhelminthes
Tissue Layers and
Organization
Nematodes have triploblastic
tissue (tri- meaning three germ
layers). They have endo- and
ectoderm as well as mesoderm.
They are more advanced
because they have an extra
inside layer.
Platyhelminthes have
triploblastic tissue (tri- meaning
three germ layers). They have
endo- and ectoderm as well as
mesoderm. They are more
advanced because they have an
extra inside layer.
Cephalization
Roudnworms have
Flatworms are the simplest
animals to have cephalization
present, which is an
advancement.
Development of a Coelom
Psuedocoelom, have a body
cavity lined partially with a
mesoderm.
No coelom.
Symmetry
Roundworms have a bilateral
symmetry, meaning that they
have one central axis which has
symmetry.
Flatworms are the simplest
animals to have a bilateral
symmetry, meaning that they
have one central axis which has
symmetry.
Reproduction
Roundworms manly produce
sexually and have different
sexes. They reproduce using
internal fertilization.
Flatworms reproduce mostly
sexually but can also perform a
form of asexual reproduction
called regeneration. Most are
hermaphordites meaning they
have both female and male
reproductive parts.
Life Cycles
Life cycle of an ascaris, the
infective eggs are swallowed,
and when they reach the small
intestines they hatch. When they
hatch they migrate through the
intentional wall into the lungs.
The larva in the lungs is coughed
up and then re swallowed. when
larva reach the small intestine for
the second time they are more
mature and latch onto the
intestinal walls and lays eggs.
The eggs go out through the
feces and the eggs in the feces
get into grass or veggies and
humans eat the infected food
and the process starts again.
An adult fluke will reproduce
sexually by transferring sperm
with another worm in the blood
vessels of the human intestines.
The embryos produce will then
be released out your feces and
somehow get into water an
become swimming larvae. At this
times they will infect the
intermediate host, commonly a
snail. After the larvae carry’s out
asexual reproduction the new
larvae are released from the
snail, and then infect the primary
host (human). They do this by
burrowing into your skin. They
make their way through the
humans body into the intestine
where they will mature and then
the process will start again.
Criteria
Nematoda
Platyhelminthes
Feeding, Excretion, and
Circulation
They exchange gases through
their body walls and they also
use their body walls to excrete
metabolic waste. They use
diffusion to carry nutrients
through their bodies. They feed
on many different organisms,
fungi, bacteria, by using their
mouths.
They are the first phylum with an
excretory system made up of
“flame cells”. Along with
cnidarians they get their nutrients
and oxygen by diffusion.
Flatworms feed on recently
deceased waste or tiny aquatic
animals. They have a singular
opening into a digestive cavity by
which food enters and excretes.
Response and Motility
They expand and contract the
length of their body to move
using specialized muscle. Also
they have a simple nervous
system consisting of several
ganglia.
Free-Living flatworms typically
move by gliding and twisting and
turning. This allows them to react
rapidly to environmental stimuli.
Also they have a more advanced
nervous system including a head
made up of ganglia that controls
the nervous system. They also
have and eyespot which can
detect light in the environment.