Phylum PoriferaChapter 26

General Characteristics• No mouth, gut, specialized

tissues or organ systems• Multicellular• Kept rigid through

deposits of calcium carbonate, silica or spongin

• Reproduce asexually through budding and/or sexually through sperm and egg

• Water enters through the central cavity, deposits nutrients, and leaves through a hole called the osculum (filter feed)

• sessile• majority are marine (salt

water) species, ranging from tidal zones to depths exceeding 8,800 metres

Gemmules• When conditions

deteriorate, for example when temperatures drop, many freshwater species and a few marine ones produce _______________,

• “survival pods,” of unspecialized cells that remain dormant until conditions improve and then either form completely new sponges or re-colonize the skeletons of their parents.

Ecological Importance

• Environmental>____________________________________

• Economical>____________________________________

• Medicinal>___________________________________

____________________________________

Phylum Cnidaria

General Characteristics• • • Have a mouth and gastrovascular

cavity with digestive enzymes• Lacks an _______________(excretory

system) and _______________________• Simple nervous system (nerve nets

and sensory cells – statocysts and ocelli)

• Soft bodied with stinging tentacles around their mouth

• Carnivores (capture prey with their nematocysts)

• Asexual reproduction: _________________

• Sexual reproduction occurs in medusa form (depending on the species, fertilization is external – chance encounter or inside an egg-carrying medusa)

Two Body Forms

1. Polyp – sessile flowerlike

2. Medusa– motile bell-

shaped

Depending on the type of cnidarian, their life cycle may include both body types.

Three Classes of Cnidarians

1. ___________________-size: few cm to a metre -freshwater-polyp and short medusa phase-usually separate sexes, but a few are hermaphroditicex: hydras

Portuguese Man-of-War

Three Classes of Cnidarians

2. ____________________-medusa is large and long-lived-polyp is a tiny larval stage-can grow up 2m in diameter-most nematocysts are harmless to humansex: Jellyfish

Three Classes of Cnidarians

3. _________________-polyp stage only-many shallow water species depend on photosynthetic symbiotic relationships-can grow up to 1mex: sea anemones and corals

Ecological Importance

•

•

•

•

Unsegmented WormsPhylum Platyhelminthes and Phylum Nematoda

General Characteristics

• _____________________• _____________________• Simple nervous system

with sensory organs and a simple brain in their anterior region (head)

• Has 3 germ layers (ectoderm, mesoderm and endoderm)

Phylum Platyhelminthes(Flatworms)

-Carnivores that feed on tiny aquatic animals, scavengers feeding on recently deceased animals, or parasites feeding on blood or tissue fluids inside their hosts body

-Use a pharynx to suck food into a gastrovascular cavity

-Undigested food is expelled through the mouth (____________________________)

-Lack a specialized circulatory and respiratory system. Depend on diffusion to transport oxygen and nutrients to their tissues and wastes out

-Have light sensitive organs ( ____________________)

Examples:>Class Turbellaria: __________________________>Class Trematoda: __________________________>Class Cestoda: ____________________________

Phylum Nematoda(Roundworms)

• Have a ____________ and an ______________

• Simple nervous system

• Bilateral symmetry• Free-living• Mostly carnivorous• Breathe and excrete

their wastes through their body walls via diffusion

• Reproduce ___________

Ecological Importance

• Mostly negative – disease causing in humans and animals– Example: Trichinella, elephantiasis,

Ascaris, etc.

Your Task: read and make notes pages 570-578

answer questions #1-5 pg 578