BIO Inverts 3 - Cnidarian, Ctenophores, Platyhelminthes

Mesoglea what and func

area between 2 dermus layers (epidermus and gastrodermus) - works as a hydrostatic skelton and provides structural support

Body type of cnid and cteno (composed of and org)

simple nervous system and muscle tissue

diploblastic organization

Polyp vs Medusa

two different body organizations

Polyp - normally asexual stage, sessile, mouth upward…they bud

Medusa - sexual stage w gonads in umbrella, motile, mouth tenticles

Polyp Cell Specialization

theres lots!

Endoderm: has cilia that produce enzymes and aid digestion

Ectoderm:

-neural cells that can sense physical conditions like light and temp

-nematocytes that poke out and poison predators *nematoblast is the precurser

Symmetry of cnid/cten

radial on the oral axis

Simple nervous system features of cnid/cten

nerve net

not integration of signal

sensory info comes from any direction

Mechanisms for Energy of cnid (corals and anemones specifically) cten/everything else

carnivorous inject with poison and they digest in gastrovascular cavity

corals and anemones get a large portion of their energy from symbiotic algae

4 Classes of Cnidaria (HSCA)

Hydrozoa, Scyphozoa (true jellyfish), Cubozoa (box jellyfish #danger), Anthozoa (flower animals - seanemonies and corals)

Coral Bleaching

mutalists zooxanthellae get expelled and they die….stress response due to climate change causing factors

Ctenophora Traits

• diploblastic, radial

• tentacles, nerve and muscle cells with genlatenous bodies

• 8 rows of ctenes for locomotion

• colloblasts (adhesive cells)

• bioluminence!

bilateral symmetry

• mirrored positions and accompanied with cephilization

Platyhelminthes Traits

• 25000 species

• aquatic or terristrial

• free living scavengers or parasites

• blind gut

Cephilization in Platys

concentration of neurons and sensory organs at anterior end - they probe @ environment

allows for directed locomotion/movement

Sensory Structures 3

• mechanoreceptors (touch)

• chemoreceptors (taste and smell)

• photoreceptors (light)

Nervous System of Plays

longitudinal nerve chords (2)

two cerebral ganglia *primitive brain

Diversity of Playtehelmenthes (TMTC)

tubellaria (freeliving planarians)

the rest are parasitic:

monogenea (ectoparasites)

trematoda (endoparasites *male lives in body of female)

cestoda (tape worms :( - very specialized and for intestine of specific vertebrates)