1. Ctenophores

2. Radial vs. bilateral symmetry and evolution of the eumetazoans

3. Phylum Platyhelminthes

Ctenophores - The Comb Jellies

Source: http://faculty.washington.edu/cemills/Ctenophores.html 	Source:http://scilib.ucsd.edu/sio/nsf/fguide/ctenophora.html

Sourece: http://faculty.washington.edu/cemills/Ctenolist.html

1. Ctenophores are:

2. Superficially similar to Cnidarians, but distinctly different:

3. One deep sea species size of football (and bright orange!), with tentacles > 60 feet! (most are much smaller)

Like aliens from another planet!

If you are hungry for more Ctenophore information, you can go to:

http://reefkeeping.com/issues/2004-03/rs/index.htm

This is not required reading for this course, but the article is interesing, and it has some nice links to follow

Symmetry, and Eumetazoan Evolution

1. Sponges not symmetrical

2. Cnidarians radially symmetrical

3. Ctenophores radial (sort of) or bilateral

3. All other forms of animal life bilateral (at least at some stage in life cycle).

Source: http://www.cals.ncsu.edu/course/zo150/mozley/fall/loweranimphy.jpg

4. The Eumetazoans probably evolved from a planula-like ancestor

Phylum Platyhelminthes

Required reading

http://web.archive.org/web/20020614014036/www.animalnetwork.com/fish2/aqfm/1998/sep/wb/default.asp

1. Traditionally divided into 3 major groups:

2. ~ 6,000 - 10,000 species! (most species parasitic)

3. The simplest bilaterally symmetrical animals

4. Three tissue layers:

5. No body cavity between digestive tract and body wall

Cross section of a flatworm: http://www2.palomar.edu/users/warmstrong/images/fworm1.gif

6. No circulatory system, no special respiratory organs, so....

7. Turbellarians - the flatworms

Freshwater "planaria" - predators/scavengers (eating other animals):

Source: http://biodidac.bio.uottawa.ca/Thumbnails/filedet.htm?File_name=TURB006P&File_type=GIF

Marine flatworms - diverse lifestyles, often are highly specialized predators:

Source: http://www.ucmp.berkeley.edu/platyhelminthes/platyhelminthes.html

Some videos of a large marine polyclad flatworm shot during Bio 152 lab spring 2016
(this species is a predator of snails!)

https://photos.app.goo.gl/seJniY3f7zeOvL9U2

https://photos.app.goo.gl/lIKmkOTs8Z76mIlX2

A large marine polyclad flatworm swimming

https://www.youtube.com/watch?v=4ji9Olvc12U

A video of a large terrestrial flatworm eating an earthworm

(More info on flatworm lifestyles at: http://web.archive.org/web/20020614014036/www.animalnetwork.com/fish2/aqfm/1998/sep/wb/default.asp)

8. Anatomy of freshwater turbellarian flatworms:

http://web.archive.org/web/20020618114805/www.animalnetwork.com/fish2/aqfm/1998/sep/wb/wbfig1.asp

http://slideplayer.com/slide/9815288/32/images/15/Gastrovascular+cavity+Nerve+cords+Mouth+Eyespots+Nervous+tissue.jpg

9. Trematoda - flukes

Example of a fluke - A gut parasite in sea urchins:

Another example of a fluke - An ecto-parasite on fish gills:

Source of two photos above: http://www.animalnetwork.com/fish/library/simage.asp?Src=aqfm_art/2001/jan/wb3.jpg

Life cycle of the fluke that causes schistosomiasis:

See page on schistosomiasis

Male and female Schistosoma mansoni (schistosomiasis trematodes) live together for years, with female held in a groove in the male's body:

See page this photo came from

10. Cestoda: Tapeworms

Source: http://www.cals.ncsu.edu/course/zo150/mozley/fall/Tapeworm1.gif

Source: http://www.marvistavet.com/html/tapeworm.html

A large tapeworm (and they can get much larger than this!):

Source: http://www.cmlto.com/photocontest/

Tapeworm lifecycles may involve multiple hosts:

• here is the life cycle of the pork tapeworm, for example (there are also other tapeworms you can get from beef, fish, or other animals):

From: http://www.humanillnesses.com/original/T-Ty/Tapeworm.html

• and here are some tapeworm cysts in a human brain:

From: http://www.isradiology.org/tropical_deseases/tmcr/chapter7/clinical6.htm