1. Jellyfish, Sponges, and Worms
Chapter 15

2. Porifera Platyhelminthes
spongin flame cells
spicules Nematoda
collar cells Annelida
Cnidaria arteries
ectoderm
endoderm
cnidocyte

3. What is an Animal? Eukaryotic Multicellular Has organized tissues
Sexual reproduction
Moves during at least part of its life
Most animals
Eat their food
Have organs

4. What is an Invertebrate?
An animal without a backbone
Most animal species are invertebrates.

5. Invertebrate Skeletons
Function
Provide mechanical support for muscle attachment
Maintain body shape
May be external or internal
May be made of limestone, silica, protein, or water

6. Phylum Porifera

7. Sponges “Pore animals” Sponges pump water through their pores
Bring food and oxygen in
Carry wastes out
All sponges live in water.
Most species live in the oceans.
Adult sponges remain attached to an object.
Embryonic sponges can swim about briefly.

8. Sponge Skeletons Spongin Spicules Made of a fibrous protein
Soft and flexible
Spicules
Made of calcium carbonate or silica
Pointed

9. Sponge Nutrition Filter feeders – filter water to obtain food
Collar cells – line the central cavity
Cells in a jellylike middle layer transport nutrients and other materials within the sponge

10. Phylum Cnidaria

13. Jellyfish Structure Two tissue layers – one cell layer thick
Ectoderm – outer layer
Endoderm – inner layer
Gastrovascular cavity – digestion
Mouth – only body opening
Tentacles surround the mouth
Nerve net throughout the body
Control some contractile fibers

14. Jellyfish Structure Hydrostatic skeleton
Primary support for the jellyfish
A jellylike mass that fills the spaces between two tissue layers

15. Obtaining food
Nematocysts – cells found in the ectoderm of the tentacles
This paralyzes or kills the prey.
The jellyfish uses contractile fibers to push its prey into its gastrovascular cavity.
A trigger in the nematocyst can cause a thin tube to be forced out of the nematocyst.
A poison is forced through the tube.

18. Digestion
Digestive enzymes released by the endoderm break down the food.
Substances which the jellyfish cannot digest are expelled through the mouth.

19. Movement
A set of contractile fibers around the rim of the jellyfish contracts.

20. Jellyfish are mostly harmless, though some deadly varieties do exist, and have been described by marine experts as the cockroaches of the sea thanks to being tough, durable and able to survive in damaged environments.
Students do not need to copy this.

22. Other Cnidarians Hydras, corals, sea anemones
Capture prey with stinging tentacles and digests it in a central cavity.
Possess radial symmetry
Several different planes could divide an animal into equal halves.

23. Radial Symmetry

26. Phylum Platyhelminthes

27. Platyhelminthes Flatworms Bilateral symmetry – two equal sides
Planarian – a free living flatworm found in freshwater streams and in soil

28. Nervous System Neurons – long, thin nerve cells
Carry impulses from one point to another
Nerve – a collection of neurons wrapped in protective coverings
Ganglion – simple brain

29. Nervous System Neurons Nerves Ganglion
Neurons – the wires that go to individual phones
Nerves – the individual wires join to form cables
Ganglion - switchboard

30. Simple Nervous System
Longitudinal nerve runs down each side of the body
Transverse nerves connect the longitudinal nerves

31. Nervous System Stimulus – something an organism can touch
Planarians respond negatively to the touch of an object.
In water, planarians normally travel upstream.
They respond positively to the touch of flowing water.

32. Nervous System Planarians respond to chemicals in water. Eye spots
For locating food
Eye spots
“Cross eyed worm”
Sensitive to the presence or absence of light
Does not see colors
Normally, a planarian respond negatively to light (turns away).

33. Digestive System Body covering is one cell layer thick
Cilia on the underside of the body help it to glide over underwater surfaces.
Mouth – on the underside, near the middle of the body
Intestine – long, branched cavity
Extends to every area of the body

34. Digestive System
Pharynx – muscular tube through which food is sucked into the intestine
Non-digestible material is pushed out of the intestine through the mouth.

35. The thinness of a planarian’s body allows for gas exchange.
Excretory system
Flame cells – cilia move water and wastes through tiny tubes to the excretory pores

36. Bottom image is a land planarian, originally from southeast Asia
Bottom image is a land planarian, originally from southeast Asia. Can reach up to 10 inches.

38. Tapeworms Common parasite of animals and humans
Found in the digestive tract
Head is equipped with hooks or suckers to attach it to the digestive tract.
Most of the body consists of reproductive segments.
Fill with eggs, are released, and exit in the animals feces.

39. Marine flatworms (polyclads) – order polycladidia

40. Other Flatworms

41. Review: Phyla Porifera Cnidaria Platyhelminthes Sponges Jellyfish
Hydra
Sea anemone
Coral
Platyhelminthes
Flatworms
Planerian
Tapeworm

42. Support What is an invertebrate?
Animal without a backbone
What provides mechanical support for muscle attachment and maintains body shape?
Skeleton
Sponge?
Spongin and spicules
Jellyfish?
Hydrostatic – jellylike substance

43. Review: Symmetry
Cnidarian
Radial
Platyhelminthes
Bi-lateral

44. Review: Miscellaneous
Filter feeder
Sponge
Possesses longitudinal and transverse nerves and ganglia
Planerian
Uses nematocysts to obtain food
Jellyfish

45. Phylum Porifera

46. Phylum Cnidaria

47. Phylum Platyhelminthes

48. Phylum Nematoda

49. Phylum Nematoda Roundworms – round, tubelike bodies
Parasites and free-living
Many are microscopic.

50. Ascaris
May be found in the intestines of various animals

51. Ascaris Life cycle Eggs are released in an animal’s intestines.
Eggs exit in the feces.
Eggs are swallowed and hatch in intestine.
Larvae burrow into the intestine walls and enter blood stream.
The larvae reach the lungs, travel up the throat, and are reswallowed.
The larvae grow into adult worms once back in the intestine.

52. Other Roundworms Parasites - hookworms, pinworms, trichina worms
Vinegar eel – contribute to the development of the unique cider taste.

53. Phylum Annelida
Polychaete in upper right hand corner (marine)

54. Phylum Annelida Segmented body plan
Earthworms, leeches, tubeworms, and polychaetes
Polychaetes include bristle worms, lungworms, fireworms and clam worms

55. The Body of an Earthworm
Epidermis – covers the body
Exchanges gases with the environment
Must be kept moist for gas exchange
Cuticle – protects the earthworm from harmful parasites and substances
Secreted by the epidermis

56. Two muscle layers - Provide support and aid in movement
When the circular muscles contract, the worm becomes longer and thinner.
When the long muscles contract, the worm becomes shorter and wider.
Bristles – aid in movement.

58. The Body of an Earthworm
Two muscle layers
Provide support
Aid in movement
Circular muscles
Longitudinal muscles
Bristles – aid in movement.

59. Sensory receptor – a structure that can sense a stimulus and start an impulse traveling along a neuron.
More in the front end (An earthworm leads with it’s front end.)
Large ganglia - Located in the third segment; Receives impulses from the front end
Small ganglia - One in each segment; Found along the length of the nerve cord.

60. Earthworm’s Nervous System
Sensory receptor – senses a stimulus and starts an impulse traveling along a neuron.
Large ganglia
Third segment
Receives impulses from the front end
Small ganglia
One in each segment
2 suprapharyngeal ganglia attached to 1 subpharyngeal ganglion

61. An earthworm eats the soil as it forms tunnels. Most is indigestible
Mouth – secretes fluids that moisten the soil.
Upper lip – helps force food into its mouth.
Pharynx
secreted liquids lubricate food
Muscle fibers help pull food into body
Esophagus – carries food from the pharynx to the crop
Crop – temporary storage
Gizzard – muscular to grind food
Intestine
Enzymes break down food
Nutrients are absorbed

62. Earthworm’s Digestive System
An earthworm eats the soil as it forms tunnels.
Most is indigestible

63. Mouth – secretes fluids that moisten the soil.
Upper lip – helps force food into its mouth.
Pharynx – Muscular organ pulls food into the body
Esophagus – carries food from the pharynx to the crop
Crop – temporary storage
Gizzard – muscular to grind food
Intestine
Enzymes break down food
Nutrients are absorbed

64. Earthworm’s Digestive System
Anus - indigestible wastes leave the body
Castings – wastes which form piles outside the earthworm’s tunnels.

65. Earthworm’s Circulatory System
Closed circulatory system – the blood never leaves the blood vessels
Open circulatory system – blood leaves the blood vessels before returning to the heart.
Aortic arches – help control blood pressure
Dorsal blood vessel – carries blood toward the aortic arches
Ventral blood vessel – carries blood away from the aortic arches

66. Earthworm Respiration and Excretion
Gas exchange occurs through skin.
Capillaries lining skin receive and release gases.
Excretion
Nephridia – looped tubes that collect wastes from the blood
Wastes leave the body through tiny pores