Animal Characteristics Sponges and Cnidarians

Zoology

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

Describe the Body Plans of Animals

1. Symmetry: balance in body proportions

a. Asymmetrical:have irregularly shaped bodies, no symmetry

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

Planes ofsymmetry

Radial

Planes of Symmetry

Dorsal

Ventral

Anterior end

Posterior endBilateral Symmetry

2. Body arrangements:

a. anterior: head regionb. posterior: tail regionc. dorsal: back or topd. ventral: abdomen or bottom

Sponges: Phylum Porifera (“pore bearer”)

• Simplest of all animals• Assymetrical • Sessile filter-feeders

whose bodies have many pores

• Obtain oxygen by filtering water

• No nervous system or organ systems

• No tissue organization

• Acoelomates

Digestion: NO SYSTEM filter feeders - chooanocytes

Excretion: NO SYSTEM Basic diffusion; wastes exit thru osculum

Circulation: NO SYSTEM- amoeboid cells

Respiration: NO SYS. diffusion-obtain oxygen from water

Reproduction: ASEXUAL AND SEXUAL

SPONGES

Section 26-2

Water flow

Choanocyte

Spicule

Pore cell

Pore

Epidermal cell

Archaeocyte

Osculum

Central cavity

Pores

 The Anatomy of a Sponge

• Outer epidermal layer

• jellylike middle layer ( amoeboid cells and spicules)

• Spongocoel- inner cavity lined with choanocytes

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 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

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Simple Sponge Morphology

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)

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Sponge Body Forms

Classes• Calcarea- spicule

made of calcium carbonate-

• Hexactinellida- glass sponge (spicule-silicon)

• Demospongia- “people’s sponge”, spicules are spongin (ex. Bath)

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Class CalcareaGrantia

• Small• Vase shape• Spicules of calcium

carbonate– Straight or 3-4 rays

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Class Hexactinellida Euplectella

• Spicules– Siliceous – 6 rays

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Class Demospongiae Spongia

• Spicules– Siliceous– spongin

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Sponge ReproductionAsexually:• Fragments break off and grow into

new individuals• Buds form from sides of parent

sponge, break offnew sponge• can grow back missing parts

(regeneration)• Gemmules: During droughts or cold

weather, some freshwater sponges produce internal buds called gemmules. A food-filled ball of amebocytes surrounded by a protective coat made of organic material and spicules

Sexually:

• Hermaphrodites: produce both eggs and sperm

• Gametes are released into water (external fertilization)larva swim to new area

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

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PoriferaPorifera PlatyhelmithesPlatyhelmithes MolluscaMollusca ArthropodaArthropoda

HemichordataHemichordataCnidariaCnidaria NemerteaNemertea AnnelidaAnnelida

EchinodermataEchinodermataChordataChordataLophophoresLophophores

ProtozoansProtozoansPrecambrian

Before 670 MYA

How much did your brain “sponge” in?

1. What are the basic characteristics of Animals?

2. What does the word Porifera mean?

3. What type of structure?a. provide the skeleton of a sponge?

b. Filter food out of the water?

c. Allows water to exit the sponge?

d. Class Hexactinellida has spicules made of?

4. How do sponges survive without body systems? (Be specific)

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Hypothesis of Multicellularity

Cnidarians• Phylum Cnidaria: “stinging cell”• Hollow gut- (coel)• radial symmetry• Germ Layers: 2

epidermalgastrodermal

• NO ORGAN SYSTEMS• Segmentation: none• Coelom: Acoelomate• Movement: sessile or motile• Have tentacles- stinging cells

found on tentacles

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

• NEMATOCYSTS tentacles that contain stinging cells(cnidocysts) used to capture and poison prey

Label the hydra on your notes!

http://www.arkive.org/common-jellyfish/aurelia-aurita/video-10.html

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: none• Circulation: none• Reproduction: asexual and sexual,

alternation of generations

Cnidarian Reproduction• Asexually: by budding

• Sexually: in medusa form only, sperm and eggs are released into water (fertilized egg zygotelarvaadult)

• Thousands of gametes are released at a time

Alternation of Generations:Video: medusa releasing from polyp

Answer the following:

Explain why sponges and cnidarians release so many

gametes into the water

Cnidarians: Body Forms

• Polyp: body with tentacles hanging upward

• Ex: hydra, sea anemone

• video polyp predation

• Medusa: body with tentacles hanging downward

• Ex: jellyfish

basal disc: sticky structure at the bottom of polyp ; sessile

Epidermis

Mesoglea

Gastroderm

Mesoglea

Gastrovascular cavity

Mouth/anus

Tentacles

Tentacles

Mouth/anus

Gastrovascularcavity

Polyp

Medusa

Structure:The Polyp and Medusa Stages

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Diploblastic - 2 germ layers

– Epidermis - outer covering (ectoderm)– Mesoglea - middle non-living jelly-like layer– gastrovascular cavity (endoderm)

Classes of Cnidarians

1.Hydrozoa:fresh water and marine, polyp and medusa present ex. Hydra, man-o-war, Obelia

2. Scyphozoans: cup- large jellyfish ex. box

3. Anthozoans: flower -all marine -polyps only

Ex: corals, sea anemoneRiches of the sea

Video jewel anenome

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Class Hydrozoa• Freshwater & marine.• Medusa and polyp colonies

which appear to be one organism-different types of polyps work together to serve the entire colony

• Ex: Hydra, Obelia, Gonionemus

Physalia (portuguese-man-of-war)

• Asexual repro.-budding.• Sexual repro. via gametes

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Class Scyphozoa• Scyph= “cup”• Large- Tentacles up

to 70 meters in length• All marine• Independent medusa

forms• Lack polyp stage or

have for a very short time

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Class Anthozoa• ANTHO=“flower”

• All polyps-Medusa stage absent

• Solitary or colonial

• Some produce protective skeletons

• All Marine

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Class AnthozoaSea Anemone

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Class AnthozoaMetridiumClass AnthozoaMetridium

MouthMouthMouthMouth

TentaclesTentaclesTentaclesTentacles

PharynxPharynxPharynxPharynx

SeptumSeptumSeptumSeptum

Gastrovascular cavityGastrovascular cavityGastrovascular cavityGastrovascular cavity

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Symbiosis

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Class AnthozoaCorals

• Protective skeleton of calcium carbonate

• Polyp retracts when not feeding

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CoralsColony of interconnected polyps

CoralsColony of interconnected polyps

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Class AnthozoaMeandrinaBrain Coral

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Class AnthozoaGorgoniaSea Fan

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Class AnthozoaTubiporaPipe Organ Coral

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Class AnthozoaActinodiscusMushroom Coral

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Class AnthozoaAcroporaStaghorn Coral

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Coral Reefs• Formed over thousands of

years from successive layers of coral skeleton deposits (calcium carbonate forms underwater mountains of coral animal skeletons)

• The underwater equivalent of the amazon jungle- very high species diversity and biomass

• Reefs contain sponges, colonial hydrozoans, anemones, many varieties of coral, fish, many types of worms we’ve not discussed, not to mention bryozoans, ctenophores, protists, bacteria, etc etc..

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Coral Reef Ecosystem

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Photo © McGraw-Hill Higher Education, Barry Barker, Photographer

Coral Reefs

• 200 C or warmer water; large formations of calcium carbonate laid down by organisms over thousands of years

1. Fringing Reef

• Less than a quarter of a mile from shore

2. Barrier Reef

• Runs parallel to shore, has a wider and deeper lagoon

3. Atoll Reef

• Reef that circles a lagoon of water rather than an island

Here they are together…

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AnthozoaScyphozoa Cubozoa

Hydrozoa

Radial symmetry, cnidocytes, planula larva

Septa divide gastrovascular cavity

Medusa cuboidal

Polyp stage reducedLoss of medusa

Cladogram of Cnidaria

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The End

Phylum Ctenophora• Characteristics• All marine • Includes comb jellies • Have eight rows of fused cilia called "comb rows" • Largest animal to move by cilia • Move by beating cilia • Lack cnidocytes but have cells sticky cells called

colloblasts that bind to prey • Colloblasts located on two ribbon-like tentacles • Have sensory structure called apical organ to detect

direction in the water • Most are hermaphrodites (make eggs & sperm) • Produce light by bioluminescence

Comb jellies