Jellyfish: Enigmatic Ocean Dwellers

1. Spineless As a Jellyfish

2. What makes something a Jellyfish? Take a second: • On a blank sheet of paper write down all of the characteristics that identify a jellyfish. • When you think of a jellyfish—what do you think of? Describe the picture in your mind • Now: Draw the jellyfish you just described.

3. Jellyfish History • Jellyfish have been around for over 650 million years • There are more than 2000 known species • Can be found everywhere from the surface of the water to the depths of the ocean

4. What is a Jellyfish? Where do they fit in? • A jellyfish is not a fish at all, it is an invertebrate in the phylumCnidaria • Cnidarians are a group of invertebrates that have stinging tentacles • This includes corals, anemones, andJELLYFISH

5. Cnidarian Characteristics All Cnidarians share the following characteristics: • Invertebrates(no backbone) • Radial symmetry(tentacles arranged around a central mouth) • Tentacles • Only 2 cell layers • Saclike digestive tract (in and out the same way) • Simple nervous system (nerve net)

6. Bounce on the Tops • The top of the jellyfish is called the medusa • It is made of 2 cell layers • Epidermis (outside) andgastrodermis(inside) • In between the layers is a jelly-like material called the mesoglea • A jellyfish is 90% water

7. Jellyfish Movement • Jellyfish float on the water because the mesoglea is less densethan the ocean • Move by contracting the medusa in a rhythmic motion • Very weak swimmers and will not swim after humans or prey

8. Living and Breathing • Oxygenwill diffuse directly INTO the cell membrane from the water • Carbon dioxide and wastes will diffuse OUT OF the cell membrane into the water

9. Feed Me: Tentacles have 2 main functions: • Tentacles: • Gather food and • Bring the food to the mouth and digest it in the cavity • CNIDOBLASTS are the stingingcellsIN the tentacles: • Little barbs in the cellscalled NEMATOCYSTSpoke into prey and disable them • They can only be used once and then need to be replaced

10. Nematocyst The barbs inside the stinging cells (cnidoblasts) that are inside tentacles and contain toxins >Now watch it in slow motion!

11. Predators and Prey • Predators (who eats jellyfish?): • Tuna • Sharks • Turtles • Prey (what do jellyfish eat?): • microscopic plankton, fish larvae, other jellyfish

12. Making More Jellyfish • The four-leaf clover on top of the jellyfish are the sex organs • Sperm cells swim out of the mouth of the male and into the mouth of the female • Egg cells are fertilized in the female ovary

13. Jellyfish Life Cycle • Larva are called planula • They attach to a substrate and develop into a POLYP • The POLYPwill mature and develop into a MEDUSA which is a free floating organism

15. Human Uses of Jellyfish • Food: 12 different species of jellyfish are used in food in southeast Asia • Bioluminescence: Scientists found a protein for bioluminescence in jellyfish and recreated it to help detect specific genes in cells

16. Jellyfish Blooms • A jellyfish happens when ocean currents and other environmental events cause there to be groupings of thousands of jellyfish! • Blooms can have a bad effect on people as they result in: • More jellyfish stings • Decline in tourism on coasts • Decline in commercial fish supplies due to jellyfish feeding • Clogging engines of boats, power plants and desalination plants

17. Jellyfish Stings • Many jellyfish stings are not deadly and only cause irritation • Some jellyfish venom can cause anaphylaxis (allergic reaction where you can’t breath)—which may result in death • Box jellyfish stings can be deadly

18. Treatment of Jellyfish Stings • Primary Goal of treating jellyfish stings: • Prevent injury to rescuers • How to treat Jellyfish stings: • Inactivate nematocysts—using vinegar or salt water(do not use alcohol, ammonia, or urine) • Remove tentacles attached to the patient - shaving the area with a safety razor or credit card also removes nematocysts

19. Largest Jellyfish • Lion’s Mane Jellyfish • Medusa can be up to 7 feet in diameter • Tentacles can reach 120 feet

20. Smallest Jellyfish • Irukandji • Only 1.5 inches across • Almost invisible

21. Most Toxic Jellyfish • Box Jellyfish • Most deadly venom in the animal kingdom (caused 5568 recorded deaths since 1954) • Found in the warm waters of Australia and Indo-Pacific

22. Amnemonemomne Sea Anemones

23. Sea Anemone Characteristics • Classified in the class Anthozoa (which means “flower animal”) • Tentacles • Radial Symmetry • Nerve net • Sessile (stationary) lifestyle

24. Feeding in the Sea Anemone • Tiny organisms and small fish swim into the tentacles and are paralyzed • Bring food to mouth • Food is digested in the digestive sac • Undigested food and wastes are eliminated through the mouth

25. Sea Anemone Life Cycle • Sea anemones do not reach a medusa stage • They live as a polyp, attached to a substrate • Reproduction: • Asexually - fission, regeneration • Sexually - male and female sex cells combine

26. Symbiosis • Symbiosis: a mutually beneficial relationship between different species • Ex: sea anemones and clownfish • Clownfish keep the anemone from being bitten by other fish • Sea anemones protect the clownfish from predators

27. Predators and Prey • Predators: grey sea slug, tompot blenny • Prey: small fish, shrimp, sea stars

28. Sea Anemone Habitat • Sea anemones are mostly found in rocky coastal areas • When the tides go out, they can be found in tide pools

29. Sea Anemones vs. Jellyfish