Phylum Platyhelminthes (Flatworms)

Which Superphylum?

Lophotrochozoa

Lophophore

feeding apparatus

cilia around the mouth

Trochophore larvae

Larva have two bands of cilia

Body Plan

Bilateral

True or False: Bilateral would suggest cephilization.

True

Tissues?

Triploblastic

Body Cavity?

Acoelomate

No body cavity

Mesoderm tissue differentiates into layer of longitudinal muscle and a layer of circular muscle. ALSO:

Mesenchymal cells that are excretory

Are they considered to be a Protostome

E yes bro

Protostome meaning?

During gastro, first hole is mouth, second is anus

Feature of body cavity

Flexibility

Eye spots are called

Ocelli

Sense light and dark

Chemical receptors

Free-living species are

predators/scavengers

Digestive system?

Incomplete

Started forming a true digestive system but stopped (still protostome)

Branching GVC

Diffusion and gap junctions

Excretory System

Has one

Network of tubules running along the periphery of the animal

Connect to flame cells with cilia that propel metabolic waste out of the body through pores (epidermis)

Nervous system?

Has one

Consists of two lateral nerve cords running the length of the body

Transverse nerves

____ cerebral ganglia surround _____ for sensing light and chemicals

Two; ocelli

Respiratory system?

Lacks

O2 is absorbed through epidermis; CO2 released

Limits thickness of body

Circulatory System?

Lacks

Gases move through diffusion and gap junctions

Transverse nerves can

Sense poking on the side of the body

Cause movement away

Mouth

Positioned at the posterior, surprisingly

Reproduction

Most species are monecious

Highly regenerative

Asexual reproduction is

Through fragmentation

Sexual reproduction is

Internal fertilization

Penis fencing