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Lab Exercise 4

PoriferaCnidaria

Platyhelminthes

Goals1. Understand the categories of animal attributes

• Level of Complexity, Symmetry, Embryological Development

2. Differentiate between phyla (Gut type, life cycles, anatomy)

3. Identify the main parts of Porifera anatomy

4. Distinguish between the Classes of Cnidarians and contrast the differences (Life cycle & Anatomy differences)

5. Name basic organs and most common Classes in Platyhelminthes on sight (Anatomy)

6. Recognize the embryological origins of major tissues in all three phyla

Organization in Animals

• Cellular level: Random assembly of cells

• Tissue level: Cells connected to form distinct tissues

• Organ level: Tissues connected to form organs

Levels of Biological Organization

• Organ system level

– All more advanced organisms

– Multiple organ systems working together form an complex organism

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Biological Symmetry

• Radial Symmetry

– Body can be divided into mirror image halves through the center

– Examples• Mature Cnidarians

Biological Symmetry

• Bilateral Symmetry

– Body is divisible into left and right halves by a single plane only

– Examples• Flatworms• Arthropods• Vertebrates

Biological Symmetry

• Asymmetry

– Body cannot be divided to produce mirror image halves

– Example• Porifera

Embryonic Development

Cell Cleavage

Blastula Gastrula

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GastrulaGastrula

(Diploblastic)

Ectoderm

Endoderm

Archenteron-Space within

endoderm

Blastopore

Archenteron: becomes adult digestive tract

Blastopore: becomes the mouth or anus

Gastrula(Triploblastic)

Blastopore

Mesoderm

Phylum Porifera

• Diploblastic

• Asymmetrical

• No digestive tissue-absorbs particles from water

Phylum Porifera

• Ostium• Choanocytes• Amoebocyte• Spicules• Spongocoel• Osculum

Ostium

Phylum Porifera— 3 Body Plans

Asconoid Syconoid Leuconoid

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Phylum Cnidaria

• Characteristics– Radial symmetry– Cnidocytes– Simple nerve net– Life cycle alternates between two forms

• Medusa• Polyp

Cnidaria - body plan

MedusaPolyp

Cnidocyte

Operculum

Cnidocil

Cnidocyte

Nematocyst

Class Hydrozoa - Hydras

• Polyps are the mature form

• Individuals or colonies

• Portuguese Man-o-war special colony

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Class Hydrozoa - Hydras

• Prey on zooplankton

• You will observe Hydra feeding on Daphnia– Look at locomotion

http://www.youtube.com/watch?v=Kukv0AtIVdU

Class Scyphozoa: Jellyfish

• Marine

• Medusas: dominant life form

• Aurelia

Oral arms

Gastric pouchMesoglea

Tentacles

Gonad

EctodermEndoderm

Class Anthozoa

• Anemones and corals

• Most complex cnidarians

• Always polyps

• Symbiosis with dinoflagellates

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Class Anthozoa - Anemones

http://www.emc.maricopa.edu/faculty/farabee/biobk/anemone.gif

basal

coelentron

pharynx

Phylum Platyhelminthes- Flat worms

• Triploblastic

• Bilateral Symmetry

• Organs

• Sac-like gut

• Acoelmate– No cavity

Class Turbellaria– Planarian spp.

• Free living

• Cephalization-– You can see where you

are going– Brain center- coordinate

movement

• Bilateral Symmetry = efficient movement

Class TurbellariaPlanarian cross-section

PharynxPharyngeal cavity Gut

Lumen of the pharynx ParenchymaGut

Ectoderm Mesoderm Endoderm

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Class Trematoda- Flukes

• Life cycle with multiple hosts

• Parasites– Opisthorchis

sinensis- Human liver fluke

Class Cestoda- Tapeworms

• Thin, ribbon-like

• Sections = proglottids

• Parasites

• Single Host

• Monoecious

• Self-Fertilizing

Hydranth

Gonangia

Class Hydrazoa Class Scyphozoa

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Class Trematoda

• Life cycle with multiple hosts