1. MONDAY 2/29/16 Learning Goal:
Describe the main characteristics of cnidarians
Explain why coral reefs are important
Warm up:
What makes up a coral reef?
Homework:
Finish all questions on packet pages 6, 7, 8, & 9
TEST on Wednesday on Ch. 9 Sec 1 & 3
MONDAY 2/29/16

2. Cnidarians
Chapter 9 Section3

3. Cnidarians Jellyfish, corals, and sea anemones
Invertebrates that have stinging cells to capture food and protect themselves
Take food into central body cavity
Cnidarians

4. Cnidarians: Body Structure
Two different body plans (vase and bowl)
Radial symmetry
Central hollow cavity
Tentacles containing stinging cells
Cnidarians: Body Structure

5. Radial symmetry - symmetry around a central axis, as in a starfish

7. Vase-shaped body plan is a POLYP
Sea anemone
Mouth opens at top
Tentacles spread out from around mouth
Most are attached to underwater surface
Body Structure: Polyp

8. Body Structure: Medusa
Bowl-shaped body plan is a MEDUSA
Jellyfish
Adapted for a swimming life
Mouths open downward and tentacles trail down
Body Structure: Medusa

9. Obtaining Food Use stinging cells to catch animals they eat (prey)
Contains threadlike structure with spines
Uses tentacles to pull prey to mouth
Takes food into central body cavity
Expels undigested food through mouth
Obtaining Food

10. Unlike adult sponges, many cnidarians move to escape danger and to obtain food
Jellyfish
Swim through the water
Hydras turn slow somersaults
Sea Anemones
Stretch out, shrink
down, bend slowly
from side to side
Movement

11. Reproduction Asexual Reproduction Sexual Reproduction
Hydras, corals, and sea anemones
Sexual Reproduction
Jellyfish
Reproduction

12. Colony Life in a Colony a group of many individual animals
Stony corals and Portuguese man-of- war
Life in a Colony

13. Stony Coral a coral reef is built by cnidarians
coral reefs are home to more species of fishes and invertebrates than any other environment on Earth
Coral polyps produce hard, stony skeletons around their soft bodies
Stony Coral

14. Portuguese Man-of-War
Contains as many as 1,000 individuals that function together as one unit
Top: gas filled chamber, allows colony to float
Bottom: polyps with different functions drift below
Some catch prey and help with digestion and reproduction
Portuguese Man-of-War