1. Invertebrates Part 1 Animal Characteristics Sponges and Cnidarians
April Adams
Zoology

2. Zoology Standards
SZ2. Students will explain the evolutionary history of animals over the geological history of Earth.  
a. Outline the geological history of Earth and discuss the major environmental changes that have occurred over time.
c. Describe the fossil record of the animals including discussing the Cambrian Explosion and major extinction events.
SZ3. Students will compare form and function relationships within animal groups (clades) and across key taxa.
a. Explain the similarities and differences among major body plans (e.g., asymmetry, radial and bilateral symmetry).
SZ4. Students will assess how animals interact with their environment including key adaptations found within animal taxa.  
a. Discuss morphological and physiological adaptations relative to ecological roles.
b. Relate animal adaptations, including behaviors, to the ecological roles of animals.
c. Explain various life cycles found among animals (e.g., polyp and medusa in cnidarians;

3. Characteristics of Animals
1. Multicellular, eukaryotes
2. Heterotrophs
3. Cells w/out cell walls, many have specialized functions
4. Usually have a method of movement
5. Most reproduce sexually
6. Require oxygen

4. Describe the Body Plans of Animals
1. Symmetry: balance in body proportions
a. Asymmetrical:have irregularly shaped bodies, no symmetry

5. b. Radial symmetry: can be divided along any plane to produce 2 halves which look alike
c. Bilateral: can be divided only one way to produce mirror image halves
Radial
Bilateral Symmetry
Posterior end
Dorsal
Ventral
Planes of Symmetry
Anterior end
Planes of symmetry

6. 2. Body arrangements:
a. anterior: head region b. posterior: tail region c. dorsal: back or top d. ventral: abdomen or bottom

7. Sponges: Phylum Porifera (“pore bearer”)
Simplest of all animals
Assymetrical animals that live in shallow waters
Sessile filter-feeders whose bodies have many pores
Obtain oxygen by filtering water
No nervous system or organ systems
No tissue organization
Acoelomates

8. SPONGES
Digestion: NO SYSTEM filter feeders / many pores .Choanocytes are flagellated cells that pull food in thru ostia (pores) and the amoebocyte cells circulate food around the organism
Excretion: NO SYSTEM Basic diffusion; wastes exit thru osculum
Circulation: None
Respiration: NO SYS. diffusion-obtain oxygen from water
Reproduction: sexual-Hermaphrodites(have sperm & egg)-Both sexes in same organism called monoecious: asexual- bud; Regenerate body parts

9. The Anatomy of a Sponge Outer epidermal layer
Section 26-2
Water flow
Osculum
Central cavity
Choanocyte
Pores
Spicule
Pore cell
Pore
Epidermal cell
Archaeocyte
Outer epidermal layer
jellylike middle layer ( amoeboid cells and spicules)
Spongocoel- inner cavity lined with choanocytes

10. Sponge Body Structures
A. Osculum: water exits-part of feeding
B. Pore cells (ostia): water enters-part of feeding
C. Collar cells:(choanocytes)- line interior, have flagella to filter out food from water
D. Amoebocytes: carry nutrients from collar cells to body of the sponge
E. Spicules- support/skeleton
F. Epithelial cells-”skin”-support/protection

11. Simple Sponge Morphology
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Simple Sponge Morphology

12. Three Body Types(Forms)
Asconoid- simple- pore cells open directly into sponge
Syconoid- more complex- pore cells open into canals
Leuconoid- most complex- pore cells open into canals that open into chamber (ex. Bath sponge)

13. Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sponge Body Forms

14. Classes Calcarea- spicule made of calcium carbonate
Hexactinellida- glass sponge (spicule-silicon)
Demospongia- “people’s sponge”, spicules are spongin (ex. Bath)

15. Class Calcarea Grantia
Small
Vase shape
Spicules of calcium carbonate
Straight or 3-4 rays

16. Class Hexactinellida Euplectella
Spicules
Siliceous
6 rays

17. Class Demospongiae Spongia
Spicules
Siliceous
spongin

18. Fig a

19. Sponge Reproduction Asexually:
Fragments break off and grow into new individuals
Buds form from sides of parent sponge, break offnew spong
can grow back missing parts (regeneration)
Sexually:
Hermaphrodites: produce both eggs and sperm
Gametes are released into water (external fertilization)larva swim to new area

20. Lifestyle and Importance
Aquatic- mostly marine
sessile as adults with free living larva
Importance- As filter feeders, they clean water in ecosystem
Large sponges filter 1500 liters/day

21. Precambrian Before 670 MYA Porifera Platyhelmithes Mollusca Arthropoda
Echinodermata
Hemichordata
Cnidaria
Nemertea
Annelida
Lophophores
Chordata
Precambrian
Before 670 MYA
Protozoans

22. How much did your brain “sponge” in?
What are the basic characteristics of Animals?
What does the word Porifera mean?
What type of structure?
provide the skeleton of a sponge?
Filter food out of the water?
Allows water to exit the sponge?
Class Hexactinellida has spicules made of?
How do sponges survive without body systems? (Be specific)

23. Hypothesis of Multicellularity
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Hypothesis of Multicellularity

24. Cnidarians Phylum Cnidaria: “stinging cell” Hollow gut
Marine animals with radial symmetry
Germ Layers: 2
epidermal
gastrodermal
NO ORGAN SYSTEMS
Segmentation: none
Coelom: Acoelomate
Movement: sessile or move
Have tentacles- stinging cells found on tentacles
Predators: capture and poison prey with stinging cells(cnidocysts) on tentacles called NEMATOCYSTS

25. One body opening (mouth) for food to enter and wastes to exit
Structures:
One body opening (mouth) for food to enter and wastes to exit
Gastrovascular cavity: interior cavity where food is digested & nutrients are circulated around the body
Nerve net: net of nerves that allow impulses to travel around the body, senses the environment
Label the hydra on your notes!

26. Without Body Systems, how do they survive?
Nervous: Cephalization absent; Nerve Net-conducts impulses
Skeleton: Hydrostatic- water pressure maintains shape
Respiration: Oxygen diffuses into body from water
Digestion: one body opening for food & wastes
Excretion:
Circulation: none
Respiration: oxygen diffuses into body from water
Reproduction: asexual and sexual, alternation of generations

27. Cnidarian Reproduction
Asexually reproduce by budding
Sexually reproduce in medusa form only, sperm and eggs are released into water (fertilized egg zygotelarvaadult)
Thousands of gametes are released at a time

28. Alternation of Generations:

29. In the box on your notes answer the following:
Explain why sponges and cnidarians release so many gametes into the water

30. Cnidarians: Body Forms
Polyp: body with tentacles hanging upward
Ex: hydra, sea anemone
Medusa: body with tentacles hanging downward
Ex: jellyfish

31. Structure:The Polyp and Medusa Stages
Epidermis
Mesoglea
Gastroderm
Tentacles
Mouth/anus
Gastrovascular cavity
Mesoglea
Gastrovascular cavity
Mouth/anus
Tentacles
Medusa
Polyp
basal disc: sticky structure at the bottom of polyp ; sessile

32. Groups & Uses of Cnidarians
3 Groups of Cnidarians:
1. Hydrozoans: colonies which appear to be one organism
Ex: Hydra, polyp, Portuguese-man-of-war,
2. Scyphozoans: independent medusa forms
Ex: jellyfish, box jelly, medusa
3. Anthozoans: colonies of polyps
Ex: corals, sea anemone
Riches of the sea