4/25/13

Objective: Phylum Cnideria

DO NOW: 

Which term below can best be used to describe the relationship between the forearm of a cat and the

forearm of an alligator?

a. vestigial

b. homologous

c. analogous

d. bottleneck

Phylum Cnideria (Hydra, Jellies, Sea Anenomies, Coral

2 Characteristics ALL Cniderians Share• Tentacles with stinging cells• Radial symmetry

- No head

- Body parts arranged like pieces of pie

Stinging Cells

• Cnidocytes: stinging cells along tentacles

• Nematocyst: type of stinging capsule

- Coiled tubule with poisonous barb

Body Form

• Polyp: cylindrical body with tentacles coming from one end

- sessile

- ex: hydras

• Medusa: umbrella-shaped with tentacles around lower edge

- Move freely

- Ex: Jellies

Nutrition

• Tentacles: maneuver food into mouth in center

• Gastrovascular cavity: digestive sac

- Fluid in cavity transport digested food to cells lining cavity, and transport waste out

Hydrozoa

• Hydras• Some coral • Portugese man-of-war

• Coloines of polyps

Scyphozoa

• Jellies

Anthozoa

• Sea anemones• Most coral animals

Phylum Cnetophora

• Comb Jellies• No stinging cells

http://video.nationalgeographic.com/video/player/animals/invertebrates-animals/other-invertebrates/jellyfish.html

http://www.youtube.com/watch?v=u0I-3wkH37w