1. (animals without backbones)
KINGDOM ANIMALIA
Lower Invertebrates
(animals without backbones)

2. PHYLUM PORIFERA - “pore bearers”
Sponges are the most ancient animals alive today.

3. Section 26.1 Summary – pages 693-697
Sponges are pore-bearers
Water out
Sponges are mainly sessile organisms.
Central
cavity
Because most adult sponges can’t travel in search of food, they get their food by a process called filter feeding. Filter feeding is a method in which an organism feeds by filtering small particles of food from water that pass by or through some part of the organism.
Water in
Section 26.1 Summary – pages

4. Section 26.1 Summary – pages 693-697
Osculum
A Sponge
Pore cell
Epithelial-like
cells
Amoebocyte
Collar cells
Direction of
water flow
through pores
Spicules
Section 26.1 Summary – pages

5. Sponges provide habitats for other animals and are symbiotic with bacteria & protists

6. CHARACTERISTICS: No Mouth Aquatic (freshwater & marine)
Lack true specialized tissues & organs. However, they do respire, obtain food, and excrete wastes
Motile larvae
Sessile adults
Filter feeders, able to pump water through its body
Internal skeleton made up of spongin and/or spicules (thin spines ) of calcium carbonate or silica.
Exhibit asymmetry – they lack body symmetry

7. PARTS OF THE SPONGE
The body forms a vaselike wall around a sac
Osculum – opening at the top of the sac. Food enters, wastes leave here

8. COLLAR CELLS – flagellated cells that line the interior of a sponge
COLLAR CELLS – flagellated cells that line the interior of a sponge. They pull a current of water into the central cavity through thousands of pores that ar located in the outer layer, and trap food (organic matter, microscopic organisms)

9. Amebocytes – Cells that move through the sponge’s body, supplying nutrients to other cells and removing wastes. They also build spicules which interlock to form the skeleton.

10. Spongin – network of protein fibers (the part you see in a sponge)
Spicules – Tiny needlelike structures

11. Section 26.1 Summary – pages 693-697
Support and defense systems in sponges
Some sponges have sharp, hard spicules located between the cell layers.
Spicules may be made of glasslike material, silica, or of calcium carbonate.
Spicules
Section 26.1 Summary – pages

12. Asexual Reproduction
1. Budding – buds detach, form new sponge or remain attached to parent

13. 2. Regeneration – Fragments broken off can settle & grow.

14. 3. Forming a sphere shaped structures called gemmules – during extreme conditions (drought or freeze) some freshwater sponges form gemmules. A gemmule is a dormant mass of sponge amebocytes surrounded by protective layers of spicules. Under favorable conditions, amebocytes grow into new sponges.

15. Sexual Reproduction
Many are hemaphrodites: produces both eggs & sperm.
Fertilization: internal or external
Mostly internal: sperm released into the water through osculum, flow into another sponge through pores, amebocytes transport the sperm to an egg.
The zygote (formed by union of sperm and egg) develops into a flagellated larva that swims away and settles on a surface. Grows into a new sponge.

16. Section 26.1 Summary – pages 693-697
Reproduction in sponges
Eggs and sperm form from amoebocytes.
During reproduction, sperm released from one sponge can be carried by water currents to another sponge, where fertilization can occur.
Section 26.1 Summary – pages

17. Section 26.1 Summary – pages 693-697
Egg
cell
Sperm
cells
Flagella
Larvae
New sponge
Section 26.1 Summary – pages

18. PHYLUM CNIDARIA (Coelenterates)
* Aquatic soft-bodies animals with stinging tentacles in circles around the mouth. Used for defense & food capture.

19. Section 26.2 Summary – pages 698-705
What is a cnidarian?
Cnidarians (ni DARE ee uns) are a group of invertebrates made up of more than species of jellyfishes, corals, sea anemones, and hydras.
They can be found worldwide, and all but a few cnidarians live in marine biomes.
Section 26.2 Summary – pages

20. Section 26.2 Summary – pages 698-705
A Cnidarian
Tentacles
A medusa is the free- swimming form of a cnidarian.
It possesses an umbrella-shaped, floating body, called a bell, with the mouth on its underside.
Section 26.2 Summary – pages

21. Section 26.2 Summary – pages 698-705
Hydra
Tentacles
Tentacles
Mouth
Nematocyst before discharge
Prey
Bud
Nematocyst after discharge
Section 26.2 Summary – pages

22. Section 26.2 Summary – pages 698-705
Reproduction in cnidarians
Female
Male
Sexual Reproduction
Eggs
Fertilization
Blastula
Asexual Reproduction
Larva
Bud
Polyp
Section 26.2 Summary – pages

23. Section 26.2 Summary – pages 698-705
Reproduction in cnidarians
Medusae
Male
Female
Asexual
reproduction
Egg
Sperm
Sexual
reproduction
Larva
Polyp
Section 26.2 Summary – pages

24. Nematocysts are the stinging cells.
Bodies have 2 layers of true tissues and radial symmetry.
Have a large hollow space called a gastrovascular cavity for food digestion.

25. Section 26.2 Summary – pages 698-705
Body structure
Mouth
A cnidarian’s body is radially symmetrical. It has one body opening and is made up of two layers of cells.
Tentacle
Cavity
Inner cell layer
Jellylike layer
Bud
Disc
Outer cell layer
Section 26.2 Summary – pages

26. Section 26.2 Summary – pages 698-705
Body structure
Mouth
The two cell layers are organized into tissues with specific functions.
Tentacle
Cavity
Inner cell layer
The inner layer is adapted mainly to assist in digestion.
Jellylike layer
Bud
Disc
Outer cell layer
Section 26.2 Summary – pages

27. Most Cnidarians are carnivores which capture and eat animals using stinging cells called nematocysts located on tentacles.
Respiration & excretion is by diffusion into the water

28. Section 26.2 Summary – pages 698-705
Digestion in cnidarians
Once captured by nematocysts, prey is brought to the mouth by contraction of the tentacles.
Mouth
Gastrovascular cavity
Polyp
Mouth
Medusa
Section 26.2 Summary – pages

29. Section 26.2 Summary – pages 698-705
Hydra eating daphnia
Digestion in cnidarians
The inner cell layer of cnidarians surrounds a space called a gastrovascular (gas troh VAS kyuh lur) cavity.
Cells adapted for digestion line the gastrovascular cavity and release enzymes over captured prey. Any undigested materials are ejected back out through the mouth.
Section 26.2 Summary – pages

30. A network of simple nerves concentrated around the mouth detect food, light, etc. They have no brain.
Cnidarians lack muscles but the medusa nerve cells can cause the bell shape to open & close like an umbrella which propels the medusa by a slow “jet-propulsion.”

31. Have 2 basic body types:
1. POLYP – vase-shaped that has its opening on the dorsal surface and tentacles that point upward.
2. MEDUSA – umbrella-shaped that has its mouth on the ventral surface and tentacles that point downward.

32. Section 26.2 Summary – pages 698-705
Body form
Most cnidarians undergo a change in body form during their life cycles.
Polyp
Medusa
Section 26.2 Summary – pages

33. Section 26.2 Summary – pages 698-705
Body form
There are two body forms, the polyp and the medusa.
Poly
Meusa
Section 26.2 Summary – pages

34. Many Cnidarians alternate between sessile polyp (flower-like) and motile medusa (bell-shaped) life forms.
Reproduction is both sexual and asexual.

35. Polyps produce asexually by budding.
Medusas produce sexually by releasing sperm and eggs into the water.
Ciliated larvae, called planula, swim to new areas and become polyps.

36. 1. CLASS Hydrozoa: Hydras, Portuguese Man of War
1. CLASS Hydrozoa: Hydras, Portuguese Man of War. Gelatinous body is mostly water. Polyp form dominant. Colonial or solitary. Sexual medusa generation & asexual polyp generation.

37. Section 26.2 Summary – pages 698-705
Scyphozoans are the jellyfishes
The fragile and sometimes luminescent bodies of jellyfishes can be beautiful.
Some jellyfishes are transparent, but others are pink, blue, or orange.
The medusa form is the dominant stage in this class.
Section 26.2 Summary – pages

38. Class Scyphozoa: Jellyfish, Sea Wasp
Medusa form dominant. Some species bypass the polyp stage

39. Class Anthozoa: Sea Anemones, Corals.
Colonial or solitary polyps.
No medusa stage.

40. Section 26.2 Summary – pages 698-705
Most anthozoans build coral reefs
Anthozoans are cnidarians that exhibit only the polyp form.
All anthozoans have many incomplete divisions in their gastrovascular cavities.
Sea Anemone
Section 26.2 Summary – pages

41. Section 26.2 Summary – pages 698-705
Most anthozoans build coral reefs
Sea anemones are anthozoans that live as individual animals, and are thought to live for centuries.
Sea Anemone
Section 26.2 Summary – pages

42. Section 26.2 Summary – pages 698-705
Most anthozoans build coral reefs
Corals that form reefs are known as hard corals.
Other corals are known as soft corals because they do not build such structures.
Section 26.2 Summary – pages

43. PHYLUM PLATYHELMINTHES (Flatworms)
Simplest animals with bilateral symmetry
Nervous system consists of sensory receptors and nerve cells.
Ganglia are clusters of nerve tissues that are concentrated at anterior end, forming primitive cephalization (head)

44. Section 26.3 Summary– pages 706-710
What is a flatworm?
The least complex worms belong to the phylum Platyhelminthes (pla tee HEL min theez).
These flatworms are acoelomates with thin, solid bodies.
Planarian
Section 26.3 Summary– pages

45. Section 26.3 Summary– pages 706-710
What is a flatworm?
There are approximately 14,500 species of flatworms found in marine and freshwater environments and in moist habitats on land.
Planarian
Section 26.3 Summary– pages

46. Section 26.3 Summary– pages 706-710
Eyespots
Head
Sensory cells
A Planarian
Mouth
Extended pharynx
Digestive
tract
Flame cell
Cilia
Nucleus
Excretory
system
Cilia
Section 26.3 Summary– pages

47. Section 26.3 Summary– pages 706-710
Feeding and digestion in planarians
A planarian feeds on dead or slow-moving organisms.
Extended
pharynx
It extends a tube-like, muscular organ, called the pharynx (FAHR inx), out of its mouth. Enzymes released by the pharynx begin digesting food outside the animal’s body.
Section 26.3 Summary– pages

48. More developed organ systems than sponges or cnidarians.
Unsegmented and appear flat.
Have 3 layers of tissues: endoderm, mesoderm, & ectoderm
Free living or parasitic
3 Classes

49. 1. Class Turbellaria (Planarians)
Free living aquatic freshwater flatworms.
Detritus feeders that move with
cilia and gliding motion
Has a straight digestive system. A single ventral opening in the middle of its body. The mouth(pharynx) through which food enters and undigested wastes leave. Often called a “tube within a tube”

50. They use muscular pharynx
They use muscular pharynx. It extends and sucks in food into its gastrovascular cavity. That forms an intestine with many branches.
Excretory system – Flame cells, small, bulblike structures excrete water and chemical wastes.

51. Circulatory and Respiratory functions are accomplished by diffusion
Circulatory and Respiratory functions are accomplished by diffusion. Does not have circulatory or respiratory system.

52. Its nervous system consists of a simple brain (nerve net or ganglion) in head with eye spots that are sensitive to light, and touch receptors that help it navigate
Moves with cilia on the ventral surface along on slime-like material that it secretes.

53. Section 26.3 Summary– pages 706-710
Nervous control in planarians
Most of a planarian’s nervous system is located in its head—a characteristic common to other bilaterally symmetrical animals.
Nerve cell mass
Section 26.3 Summary– pages

54. Section 26.3 Summary– pages 706-710
Nervous control in planarians
Some flatworms have a nerve net, and others have the beginnings of a central nervous system.
Nerve cell mass
Section 26.3 Summary– pages

55. Section 26.3 Summary– pages 706-710
Nervous control in planarians
A planarian’s nervous system includes two nerve cords that run the length of the body.
Ganglia
Eyespots
Nerve cord
Muscle cells
Section 26.3 Summary– pages

56. Section 26.3 Summary– pages 706-710
Nervous control in planarians
It also includes eyespots that can detect the presence or absence of light and sensory cells that can detect chemicals and movement in water.
Ganglia
Eyespots
Nerve cord
Mscle cells
Section 26.3 Summary– pages

57. Section 26.3 Summary– pages 706-710
Nervous control in planarians
At the anterior end of the nerve cord is a small swelling called a ganglion (plural, ganglia). The ganglion receives messages from the eyespots and sensory pits, then communicates with the rest of the body along the nerve cords.
Ganglia
Messages from the nerve cords trigger responses in a planarian’s muscle cells.
Section 26.3 Summary– pages

58. Reproduction is sexual or asexual
Planarians are hemaphrodites. Two worms pair up with each worm delivering sperm to the other, fertilizing each other’s eggs
Asexual reproduction is by binary fission and is able to regenerate missing parts.

59. Section 26.3 Summary– pages 706-710
Reproduction in planarians
If a planarian is cut horizontally, the section containing the head will grow a new tail, and the tail section will grow a new head.
Section 26.3 Summary– pages

60. Section 26.3 Summary– pages 706-710
Reproduction in planarians
Thus, a planarian that is damaged or cut into two pieces may grow into two new organisms—a form of asexual reproduction.
Section 26.3 Summary– pages

61. 2. Class Trematoda – Flukes
External parasites on hosts including humans
Usually 2 different hosts in the fluke life cycle
Most absorb blood from the host
Some have tough, protective body coverings that prevent hosts from digesting them

62. Some have hooks that help them attach to their hosts
Some have suckers which they use to attach to a host or to ingest a host’s cells and body fluids

63. Blood flukes, genus Schistosoma, cause a serous disease, schistosomiasis. It results in allergic responses, swelling, ulcers, and liver damage.

64. Reproduction is similar to reproduction in planarians
Transmitted to humans in drinking water from contaminated streams.

65. Section 26.3 Summary– pages 706-710
The life cycle of a fluke
Adult flukes
Embryos
released
Larva
Human
host
Snail host
Larva
Section 26.3 Summary– pages

66. 3. Class Cestoda- Tapeworms

67. Internal parasites, including humans

68. Usually involves 2 or more hosts in the life cycle

69. Have a head called a scolex with hooks and suckers

70. Has repeating body section called proglottids containing male or female sex organs.

71. Section 26.3 Summary– pages 706-710
Tapeworm bodies have sections
Hooks
The body of a tapeworm is made up of a knob-shaped head called a scolex (SKOH leks), and detachable, individual sections called proglottids.
Scolex
Sucker
Proglottid
Mature proglottid
with fertilized eggs
Section 26.3 Summary– pages

72. Section 26.3 Summary– pages 706-710
Tapeworm bodies have sections
Hooks
A proglottid (proh GLAH tihd) contains muscles, nerves, flame cells, and male and female reproductive organs.
Scolex
Sucker
Proglottid
Mature proglottid
with fertilized eggs
Section 26.3 Summary– pages

73. Food is absorbed from the hosts intestines

74. They have neither a mouth or digestive systems
They have neither a mouth or digestive systems. They absorb nutrients through their body walls

75. Section 26.3 Summary– pages 706-710
Feeding and digestion in parasitic flatworms
A parasite is an organism that lives on or in another organism and depends upon that host organism for its food.
Hooks
Scolex
Sucker
Proglottid
Parasitic flatworms have mouthparts with hooks that keep the flatworm firmly attached inside its host.
Mature proglottid
with fertilized eggs
Section 26.3 Summary– pages

76. Have an excretory, nervous, and reproductive systems.

77. Tapeworms are consumed by cattle with the grass they eat that contain tapeworm eggs. The eggs hatch into larvae that travel to the muscles. People become infected by eating undercooked meat

78. These worms grow 30 feet long inside humans and produce ½ billion eggs per year

79. Phylum Nematoda (Roundworms)

80. Section 26.4 Summary– pages 711-713
What is a roundworm?
Roundworms belong to the phylum Nematoda.
They are widely distributed, living in soil, animals, and both freshwater and marine environments.
Most roundworm species are free-living, but many are parasitic.
Roundworm
Section 26.4 Summary– pages

81. Examples: ascaris, hookworms, trichinella
Examples: ascaris, hookworms, trichinella. They cause intestinal blockage.

82. Have tube-like digestive system with 2 openings: mouth and anus

83. Mostly free-living

84. Bilateral symmetry

85. Hydrostatic Skeleton – made up of muscles that surround, and are supported by a water-filled cavity. Water pressure keeps the body firm, like air pressure in a tire.

86. Circulatory System – the hydrostatic skeleton also serves as a circulatory system carrying materials throughout a roundworm’s body.

87. Nervous System consists of sensory receptors and nerve cells
Nervous System consists of sensory receptors and nerve cells. Ganglia are clusters of nerve tissues that are concentrated at the anterior end to form primitive cephalization (head)

88. Some are parasites

89. They move by thrashing. The hydrostatic skeleton allows the muscles to push against the water-filled cavity to cause movement

90. Reproduce sexually

91. Section 26.4 Summary– pages 711-713
What is a roundworm?
Roundworms are tapered at both ends.
They have a thick outer covering, which they shed four times as they grow, that protects them in harsh environments.
Intestine
Anus
Mouth
Round body
shape
Section 26.4 Summary– pages

92. Section 26.4 Summary– pages 711-713
What is a roundworm?
Roundworms have a pseudocoelom and are the simplest animals with a tubelike digestive system.
Roundworms have two body openings—a mouth and an anus.
Intestine
Anus
Mouth
Round body
shape
Section 26.4 Summary– pages

93. Section 26.4 Summary– pages 711-713
What is a roundworm?
The free-living species have well-developed sense organs, such as eyespots, although these are reduced in parasitic forms.
Intestine
Anus
Mouth
Round body
shape
Section 26.4 Summary– pages

94. Section 26.4 Summary– pages 711-713
Roundworm parasites of humans
Trichinella causes a disease called trichinosis (tri keh NOH sis).
This roundworm can be ingested in raw or undercooked pork, pork products, or wild game.
Trichinella
Section 26.4 Summary– pages

95. Section 26.4 Summary– pages 711-713
Roundworm parasites of humans
Hookworm infections are common in humans in warm climates where they walk on contaminated soil in bare feet.
Hookworms cause people to feel weak and tired due to blood loss.
Section 26.4 Summary– pages

96. THE END

97. TEST REVIEW The Lower Invertebrates

98. Carnivore b. Herbivore c. Parasite Filter feeder e. Detritus feeder
Animal that lives on and absorbs food from a host.
Animal that eats other animals.
Animal that eats only plants.
Animal that strains plankton from water.
Animal that feeds on bits of dead, decaying organisms.
Parasite
Carnivore
Herbivore
Filter Feeder
Detritus Feeder

99. The side of an animal considered to be its back or top side.
Posterior b. Anterior c. Dorsal d. Ventral
The side of an animal considered to be its back or top side.
The end of an animal where the head is located.
The side of an animal considered to be it’s front or bottom(stomach).
The end of an animal where the anus is usually located.
Dorsal
Anterior
Ventral
Posterior

100. An animal without a backbone.
a. Invertebrate b. Vertebrate c. Bilateral d. Radial
An animal without a backbone.
An animal having a symmetry similar to a cylinder.
An animal with a backbone.
An animal having a symmetry with two halves alike, having an anterior & posterior.
Invertebrate
Radial
Vertebrate
Bilateral

101. Thin skeletal-like spines made of calcium carbonate or silica.
Spicules b. Collar cells c. Amebocytes d. Gemmules
Flagellated cells that pull water through pores in a sponge to a central chamber.
Motile cells that move around in a jelly-like layer of a sponge to build skeletal material
Thin skeletal-like spines made of calcium carbonate or silica.
Sphere shaped collection of cells for asexual reproduction.
Collar Cells
Amebocytes
Spicules
Gemmules

102. Porifera b. Cnidaria c. Platyhelminthes d. Nematoda
Phylum of animals having species that capture prey with tentacles bearing nematocysts.
Phylum of animals that filter their food from water currents flowing through their bodies.
Phylum of animals with some species that absorb their food already digested by a host using hooks and suckers on a head.
Phylum of animals having a straight digestive system with a mouth and an anus, often called a “tube within a tube.”
Cnidaria
Porifera
Platyheleminthes
Nematoda

103. a. Polyp b. Medusa c. Hydra d. Jellyfish e. Sea Anemone
22. An example of species in Class Anthozoa consisting of solitary polyps with no medusa.
Commonly the sessile flower-like stage in Cnidarians.
An example of species of Class Hydrozoa.
An example of species in Class Scyphozoa in which the dominant form is a solitary medusa.
Commonly the motile bell or umbrella shaped stage in the lifecycle of Cnidarians.
Sea
Anemone
Polyp
Hydra
Jellyfish
Medusa

104. A. Scolex B. Osculum C. Pharynx D.Mouth
27. An organ in planarians that extend and sucks in food.
28. A head-like organ in tapeworms with hooks and suckers.
29. An exit for water currents used by sponges in food getting.
30. An opening to a tube that ends with an opening called an anus.
Pharynx
Scolex
Osculum
Mouth

105. Platyhelminthes b. Nematoda c. Turbellaria d. Trematoda e. Cestoda
Class of flat worms including tapeworms that are internal parasites on at least two different hosts in its lifecycle including man.
Phylum of roundworms including parasites of man such as hookworms and Trichinella worms but also many free-living beneficial species found in soil.
Class of flatworms including flukes that are external and internal parasites on at least two hosts and may include man.
Phylum of flatworms having primitive cephalization, bilateral symmetry and three layers of tissues.
Class of flatworms including planarians which are free-living freshwater detritus feeders.
Cestoda
Nematoda
Trematoda
Platyhelminthes
Turbellaria

106. a. Planaria b. Tapeworm c. Hydra d. Fluke e. Sea Anemone
Class Anthozoa
Class Turbellaria
Class Cestoda
Class Trematoda
Class Hydrozoa
Sea Anemone
Planaria
Tapeworm
Fluke
Hydra

107. a. Hydra b. Fluke c. Jellyfish
Moves by somersaulting
Eats by aborbing nutrients from a host
Gelatinous body is mostly water
Hydra
Fluke
Jellyfish

108. Eats phytoplankton caught by stinging cells
a. Sponge b. Planaria c. Tapeworm d. Hydra
Eats phytoplankton caught by stinging cells
Has a motile larva and sessile adult
Attaches to host by hooks and suckers
Mouth and anus are at the end of a tube (a single tube).
Hydra
Sponge
Tapeworm
Planaria

109. .
You will need to study the illustrations to recognize major structures and the organisms.