1. Characteristics of Animals
Sponges and Cnidarians

2. Invertebrates make up over 95% of all named phyla of animals
Invertebrates make up over 95% of all named phyla of animals. There are over 30 different phyla.
Animals started an explosion of evolutionary differentiation during the Cambrian Period. This was possible by mutations in Hox genes allowing for new traits/physiology to emerge.
Animals are placed in groups based on characteristics such as Body Symmetry; Tissue Layers; and Development Patterns

3. Symmetry
the arrangement of body structures relative to some axis of the body
Asymmetrical
Radial
Bilaterial

4. Body Plan Symmetry:
Bilateral Symmetry – can be divided equally along one plane, forms mirror-image sides
Radial Symmetry – body parts are arranged in a circle around a central axis
Asymmetrical - no symmetry (typically found in Porifera)
Body Plan Terms

5. ANIMAL SYMMETRY:

6. The Animal Kingdom Multicellular Eukaryotic Heterotrophs
Cells lack cell walls
95% are invertebrates

7. What Animals Do to Survive
Feeding
Respiration
Circulation
Excretion
Response
Movement
Reproduction

8. Trends in Animal Evolution
Cell specialization and levels of organization
Early development
Body symmetry
Cephalization
Body cavity formation

9. Phylum Porifera Sponges
Have tiny openings, or pores, all over their bodies
Sessile: they live their entire life attached to a single spot
They are animals! Why…?

10. SPONGES

11. Sponges
Sponges are really nothing but a loose aggregation of specialized cells.
Of the 6,000 known spp. nearly all are marine.
Amazingly enough, these cells don’t actually form organs, but do serve similar functions, keeping the animal(s) alive.
James Fatherree

12. Sponges are Animals!!! Multicellular Heterotrophic No cell walls
Contain a few specialized cells

13. Form and Function in Sponges
Have nothing resembling a mouth or gut
Have no tissues or organ systems
Simple functions are carried out by a few specialized cells

14. General Sponge Types
Sponges fall into several basic categories, mostly depending on
shape:
branching
tubular
round
encrusting
glass
boring (destructive)
Hawaiian encrusting sponge
Sclerosponge (CaCO3)
Ceratoporella nicholsoni
Harvested sponges

15. Asymmetrical Symmetry
Have no front or back ends, no left and right sides
A large, cylindrical water pump
The body forms a wall around a large central cavity through which water flows continually

16. Choanocytes
Specialized cells that use flagella to move a steady current of water through the sponge
Filters several thousand liters/day

17. Osculum
A large hole at the top of the sponge, through which water exits
The movement of water provides a simple mechanism for feeding, respiration, circulation and excretion

18. Simple Skeleton
Spicule: a spike-shaped structure made of chalk-like calcium carbonate or glasslike silica in hard sponges
Archaeocytes: specialized cells that make spicules

19. Feeding Filter feeders Sift microscopic food from the water
Particles are engulfed by choanocytes that line the body cavity

20. Respiration, Circulation, & Excretion
Rely on the movement of water through their bodies to carry out body functions
As water moves through the cavity:
Oxygen dissolved in the water diffuses into the surrounding cells
Carbon dioxide and other wastes, diffuse into the water and are carried away

21. Response No nervous system
Many sponges protect themselves by producing toxins that make them unpalatable or poisonous to potential predators

22. Reproduction Sexually or asexually
A single spore forms both eggs and sperm; usually at different times

23. Sexual Reproduction
Internal fertilization: Eggs are fertilized inside the sponge’s body
Sperm are released from one sponge and carried by currents to the pores of another sponge

24. Sexual reproduction Many sponges are hermaphrodites, containing
male and female reproductive
capabilities, yet do not self-
fertilize.
Tube sponges, such as this
Verongia archeri which is
common in Caribbean waters
use broadcast spawning to
disperse sperm and eggs in
a flurry of activity that is
often coordinated with lunar
cycles.

25. Asexual Reproduction Budding
Gemmules: groups of archaeocytes surrounded by spicules

26. Still, if you carve ‘em up, they come back for more!!
It’s more amazing than that. If you mix groups of sponges together,
they will usually reorganize into their original groups.

27. Ecology of Sponges
Ideal habitats for marine animals such as snails, sea stars, sea cucumbers, and shrimp
Mutually beneficial relationships with bacteria, algae and plant-like protists
Many are green due to these organisms living in their tissues

28. Ecology of Sponges
Attached to the seafloor and may receive little sunlight
Some have spicules that look like cross-shaped antennae
Like a lens or magnifying glass, they focus and direct incoming sunlight

29. Sea anemones, jellyfishes, coral, etc.
Phylum Cnidaria
Sea anemones, jellyfishes, coral, etc.

30. Cnidarians Phylum Cnidaria Hydras, jellies, sea anemones, and corals
Soft-bodied
Carnivorous
Stinging tentacles arranged in circles around their mouths
Simplest animals to have body symmetry and specialized cells

31. General Cnidarian Structure and Function
Macrorhynchia phillipina
General Cnidarian Structure and Function
Centrally located mouth
Oral surface (mouth)
Aboral surface (opposite end)
Tentacles
Gut
Nematocysts (cnidae)!
Polyp and Medusa: reproductive
stages
Beautiful, but deadly! This colonial
hydrozoan still contains cnidae.

32. Cnidocytes Stinging cells that are located on their tentacles
Used for defense and to capture prey

33. Nematocyst
A poison-filled, stinging structure that contains a tightly coiled dart
Found within cnidocytes

34. Form and Function in Cnidarians
Only a few cells thick
Simple body systems
Most of their responses to the environment are carried out by specialized cells and tissues

35. Radially Symmetrical
Central mouth surrounded by numerous tentacles that extend outward from the body
Life cycles includes a polyp and a medusa stage

36. Body Plan
Polyp: cylindrical body with arm-like tentacles; mouth points upward
Medusa: motile, bell-shaped body; mouth on the bottom

38. Feeding
Polyps and medusas have a body wall that surrounds an internal space: the gastrovascular cavity
Gastrovascular cavity: a digestive chamber with one opening
Food enters and wastes leave the body

39. Respiration, Circulation, & Excretion
Following digestion, nutrients are usually transported throughout the body by diffusion
Respire and eliminate wastes by diffusion through body walls

40. Response
Specialized sensory cells are used to gather information from the environment
Nerve net: loosely organized network of nerve cells that together allow cnidarians to detect stimuli
Distributed uniformly throughout the body in most species
In some species it is concentrated around the mouth or in rings around the body

42. Response
Statocysts: groups of sensory cells that help determine the direction of gravity
Ocelli: eyespots made of cells that detect light

43. Portuguese Man of War - cnidarian that floats in the water and has long tentacles

44. Carukia barnesi: the baddest of the bad!
Irukandji syndrome:
A sting from this little guy can cause the following:
“It begins with a mild sting, followed by severe lower back pain,
muscle cramps in arms, legs, stomach and chest. It causes sweating,
anxiety, nausea, vomiting, headaches and palpitations, and has also
been known to cause cardiac failure.”

45. Movement
Hydrostatic skeleton: a layer of circular muscles and a layer of longitudinal muscles that enable cnidarians to move

46. Reproduction: Sexually and Asexually
Polyps can reproduce asexually by budding
External sexual reproduction
The sexes are separate-each individual is either male or female
Both egg and sperm are released into the water

47. CNIDARIANS

48. Groups of Cnidarians Jellies (formerly jellyfishes)
Hydras and their relatives
Sea anemones
Corals

50. Types of Cnidaria Cnidaria come in all shapes and sizes.
Sea fan
Cnidaria come in all shapes and sizes.
Hydrozoans- feathey hydroids
Siphonophores- man-o-war
Scyphozoans- large jellyfish
Anthozoan-sea anemones and coral
Most of the animals found within Cnidaria
are all carnivores.
multiple comb jellies

51. Ecology of Corals The worldwide distribution is determined by:
Temperature
Water depth
Light intensity
Many suffer from human activity
Coral bleaching has become common
Global warming may add to the problem

52. http://video. nationalgeographic

53. Multimedia
Sponge Images and Videos -
Cnidarian Images and Videos -
General Invertebrate Movies at National Geographic 
--- really good video on the portuguese man of war (under invertebrates)
Hydra Video at