Colonial-> 2 Tissue Layers -> 3 Tissue Layers

The 5 Phyla:

1.     Porifera: Sponges

        Anatomy: epidermis, mesophyl, osculum, spongecoel, porocytes, choanocyte, amoebocyte, spicules
        Charactors: sessile, no true tissues- cells can reorganize into a sponge after being sieved.
2.     Cnidarida:

        Classes: Jellyfish (Scyphozoa), Corals & Anemones (Anthozoa), Hydra (Hydrozoa)
        Anatomy: polyp and/or medusa, mouth=anus, tentacles, gastrodermis, epidermis, mesoglea, gastrovascular cavity
        Charactors: radial symmetry, diploblastic with gastrovascular cavities, cnidocytes w/nematocysts
3.     Platyhelminthes: Flatworms

        Anatomy: eyespots, ganglia, gastrovascular cavity, pharynx, ventral nerve cords
        Charactors: acoelomate, bilateral, triploblastic lacking body cavities. Many are parasitic.
4.     Nematoda: Roundworms

        Anatomy: all muscles longitudinal: only thrashing motion possible
        Charactors: pseudocoelomate, complete digestive tract, red blood, 80,000 species known so far. Many are parasitic.
5.     Mollusca:

        Classes: Clams (Bivalvia), Snails (Gastropod), Octopi, Cuttlefish, Squid, & Nautilus (Cephalopods)
        Anatomy: foot, visceral mass, mantle, mantle cavity, intestine, mouth, shell, stomach, heart, ceolom, anus, gill
        Charactors: coelomate, protostomate, complex and variable form, more than 50,000 species
        Convergence: Eyes of Vertibrates and Cephalopods
        Octopi have no blind spot, even though they DO have an optical nerve
        Cephalopods also have a closed circulatory system, unlike other moluscs

Corals are NOT interconnected. Each polyp is on it's own. See p. 636 of the textbook.

ANIMAL DIVERSITY LAB II
* Which phylum contains an asymmetrical body plan and lacks tissues, organs, and a neural network?
* Know the difference between spicules and spongin.
* What is the central cavity in sponges called?
* What is an osculum?
* What is the function of choanocytes.  Amoebocytes?
* What is the motile juvenile phase of sponges called?
* Be able to distinguish between the three classes of sponges.
* There are three different body plans found in sponges.  Which body plan is considered to be the most simplest? The most complex?
* What feature separates cnidarians from all other animal taxa?
* What are nematocysts?
* In the phylum Cnidaria, where are prey digested?
* Understand the difference between polyp and medusa forms.  Give an example of each.
* Be able to explain the generalized life cycle of cnidarians.
* Be able to distinguish the three classes in the phylum Cnidaria, i.e., which class exists only in the polyp form?  Which class exhibits the most variability in body form and life cycle?  What class, in general, exhibits the dominate medusa stage in its life cycle?
* What photosynthetic protist maintains a mutualistic relationship with corals?  When they take up residence in corals, they loose their characteristic cellulose plates and flagella.  What are they then referred to as?
* Know the difference between aceolomate and pseudocoelomate.
* Which phylum exhibits a pseudocoelom?
* Of the four classes found in the phylum Platyhelminthes, which one is nonparasitic (free-living)?  Which class contains the flukes?  Tapeworms?
* Know the four common classes in the phylum Mollusca, i.e., be able to place organisms into their appropriate classes, e.g., what class does snails, slugs and nudibranchs belong to?
* All organisms within the phylum Mollusca always include three main parts.  What are they and what is the function of each?
* What is the function of a radula?
* Which class contains the only mollusks with a closed circulatory system?
* What is the largest of the molluscan classes?
* Explain what is meant by torsion.

LAB #2:  PHYLUM PORIFERA, CNIDARIA, PLATYHELMINTHES, NEMATODA, AND MOLLUSCA
 

I.  PHYLUM PORIFERA ? SPONGES

*Aquatic, largely marine animals.
* Asymmetrical body plan.
* Aceolomates (lack an enclosed body cavity).
* Lack tissues, organs, and neural network.
* Perforated with pores (ostia).
* Internal skeleton composed of spicules (siliceous material) or spongin (fibrous material)
* Water is drawn through the pores into a central cavity, spongocoel; water exits through a larger opening called the osculum.
* Suspension feeders; have structures called choanocytes which contain flagella that generate a water current; choanocytes trap food particles and ingest them by phagocytosis.
* Amoebocytes take up food from the choanocytes, digest it, and carry nutrients to other cells.
* Reproduce sexually and asexually; motile juvenile phase is called the amphiblastula; adults are sessile.

There are three classes of sponges; based on internal skeletal structure:

1. Calcarea (calcareous sponges) ? skeleton composed of calcium carbonate; simplest of sponges.
2. Hexactinellida (glass sponges) ? skeleton composed of siliceous material fused into a network.
3. Demospongiae (natural or bath sponges) ? skeleton composed of spongin or spicules,  or both.

Sponges exhibit three different body plans.

1. Asconoid ? simplest body plan; ostia opening into an incurrent canal which then leads into the spongocoel.
2. Syconoid ? ostia leads into incurrent canals, then feeds into excurrent canals which then leads into the spongocoel.
3. Leuconoid ? further elaboration of the syconoid body form.

II.  PHYLUM CNIDARIA ? HYDRAS, JELLYFISHES, SEA ANEMONES, AND CORAL ANIMALS

* Primarily marine animals.
* Radially symmetrical.
* Aceolomates (lack an enclosed body cavity).
* Tissues and a nerve net present; capable of movement.
* Contain cnidocytes which are stinging cells that contain nematocysts that are used to capture prey.
* Prey is digested in the gastrovascular cavity.
* Two different forms present ? a sessile polyp which is a cylindrical form containing a mouth with tentacles, e.g., hydras and sea anemones; a floating medusa, free-living form which is a flattened, mouth-down version of a polyp, e.g., jellyfishes.
*Reproduce both sexually and asexually.

Generalized life-cycle of cnidarians

a. A sessile polyp reproduces asexually which produces the medusa.
b. The medusa then reproduces sexually by release of sperm and egg into the sea.
c. The zygote develops into what is called a planula that swims about until a suitable resting area is located where it then develops into a polyp.

There are three classes within the phylum:

1. Hydrozoa ? exhibit the greatest variability; alternates between polyp and medusa stages.
2. Scyphozoa (jellyfishes) ? the medusa stage generally dominates in the life cycle; most scyphozoans go through a small polyp stage, but jellyfishes that live in the open ocean have generally eliminated the sessile polyp.
3. Anthozoa (sea anemones and corals) ? occur only as polyps.

III.  PHYLUM PLATYHELMINTHES ? FLATWORMS

* Bilaterally symmetrical.
* Contain internal organs that are more complex than cnidarians, simple nervous system, and rudimentary excretory system; lack organs specialized for gas exchange and circulation.
* Lack a body cavity (aceolomate) as do sponges and cnidarians but contain three-tissue layers (ectoderm, mesoderm, endoderm).

There are four classes within the phylum:

1. Turbellaria ? nearly all are free-living (nonparasitic) and mostly marine.
2. Trematoda (flukes) ? live as parasites in or on other animals.
3. Cestoda (tapeworms) ? parasitic flatworms that live mostly in vertebrates.
4. Monogenea ? ectoparasites of fish and other aquatic vertebrates.

IV.  PHYLUM NEMATODA ? ROUNDWORMS

* Nearly ubiquitous and abundantly diverse.
*Found in most aquatic habitats, e.g., in wet soil, in the moist tissues of plants, and in the body fluids and tissues of animals.
*Bilaterally symmetrical.
* Contain three tissue layers as in flatworms but have developed a pseudocoelom (a fluid-filled body cavity that allow organs to float).
* Outer surface is covered by a thick multi-layered cuticle.
* Contain a complete digestive tract but lack a circulatory system.

V.  PHYLUM MOLLUSCA ? SNAILS AND SLUGS, OYSTERS AND CLAMS, AND OCTOPUSES AND SQUIDS
 

* Most are marine animals, though some inhabit fresh water, and there are snails and slugs that live on land.
* Bilaterally symmetrical
* Contain a true coelom (body cavity filled with fluid lined with special mesodermal lining called a peritoneum; unlike a pseudocoelomate, the organs are slung in pouches of peritoneum rather than floating within the cavity).
* Soft-bodied organisms; usually protected by a hard shell made of calcium carbonate; squids and octopuses have reduced shells that have been internalized, or lost their shells completely during evolution.
* All have a similar body plan, contain three main parts:  a muscular foot, usually for movement; a visceral mass, containing most of the internal organs; and a mantle, a heavy fold of tissue that drapes over the visceral mass and may secrete a shell.
* Contain gills, though in some they are secondarily lost.
* The radula is a rasping structure used for feeding.

There are eight classes belonging to the phylum; listed below are 4 of the most common classes:

1. Polyplacophora (chitons) ? marine animals with oval shapes and shells divided into eight dorsal plates; attaches to rocks in the intertidal via its foot, acts like a suction cup which is almost impossible to dislodge; grazers that use their radulas to cut and ingest algae.
2. Bivalvia (clams, oysters, scallops, mussels) ? have shells that are divided into two halves; abductor muscles close the shells tightly to protect the soft-bodied organim; foot used for digging and anchoring; mantle cavity contains gills used for feeding and gas exchange.
3. Gastropoda (snails, slugs, limpets, whelks, abolone, nudibranchs) ? largest of the molluscan classes; during embryonic development, one side of the visceral mass grows faster than the other causing the visceral mass to rotate up to 180 degrees (process known as torsion); most are protected in spiraled shells (lost in slugs and nudibranchs and highly modified in others); many have a distinct head with 1 or two pair of antennae.
4. Cephalopoda (octopus, squid, cuttlefish, nautilus) ? built for speed, an adaptation that fits their carnivorous lifestyle; octopuses lack a rigid skeleton, but squid and cuttlefish have an internal skeleton; contain a large prominent head with well developed eyes; a beak-like jaw, which is surrounded by 8-10 tentacles, is used to subdue prey; cephalopods have a well-developed nervous system with a complex brain capable for learning and memory; are the only mollusks with a closed circulatory system, a type of blood vascular system in which blood is always contained in vessels.

TWO MAJOR ANIMAL LINEAGES:
 

Protostomes Deuterostomes

Egg cleavage pattern:
Spiral cleavage ? produces unequally-sized spirally arranged cells.
 Egg cleavage pattern:
Radial cleavage ? produces equal-sized cells that lie directly above one another.
Determinate cleavage ? cleavage of the fertilized egg is determinate, i.e., if the egg is allowed to undergo a few cell divisions and the cells are then separated, each cell develops into only a partial embryo.
 Indeterminate cleavage ? cells separated after several cell divisions can still develop into complete embryos.
Blastopore becomes mouth
 Blastopore becomes anus
Mesoderm derives from cells on lip of blastopore
 Mesoderm derives from walls of developing gut
Mesoderm splits to form coelom Mesoderm usually outpockets to form coelom

Blastula ? A hollow sphere of cells surrounded by a central cavity; eventually becomes the gastrula.
Gastrula ? An embryo forming the characteristic three cell layers (ectoderm, endoderm, and mesoderm) which will give rise to all of the major tissue systems of the adult animal.
Blastopore ? An opening from the digestive tract to the exterior of the gastrula.
Blastocoel ? The central hollow cavity of the blastula.

Aceolomates ? organisms which lack an enclosed body cavity.
Pseudocoelomates ? organisms which contain a fluid-filled body cavity that allow organs to float.
Coelomates ? organisms which contain a body cavity filled with fluid lined that is lined with special mesodermal tissue called a peritoneum; unlike a pseudocoelomate, the organs are slung in pouches of peritoneum rather than floating within the cavity.
 

Sponges and cnidarians represent a different animal lineage and do not fall under the protostome or deuterostome lineage; flatworms are neither classified as protostomes nor deuterostomes.

Roundworms and mollusks are protostomes.
 

Animal Lab 3 vocab:

* Phylum Annelida (worms)

* Charactors: 3 cell layers, true coelom, schizocoelous (protostomate), closed circulatory system, heart, vental nerve cord, segmented, setae
* Classes:

* Polychaeta: marine, parapodia, eyes
* Oligochaeta: terestrial or fresh water, no parapodia or eyes (earthworms)
* Hirudinea: parasitic, no parapodia or eyes, no internal segmentation (leaches)
 
 

Arthropods (nolonger a phyla, now split into the below phyla)

* Charactors: chitinous, segmented, jointed legs, open circulation, ventral nerve
* Phyla:
 
 

1. Chelicerata (horseshoe crab, sea spiders, arachnids)

* Charactors: 8 legs, chelicerae, cannibals, ovipary or vivipary, compound eyes, pedipalps, book lungs

2. Crustacea

* Charactors: cephalothorax, carapace, 2 pr. antennae, mandibles
* Classes: Decapoda (crab, shrimp, crayfish, lobster), Isopoda (sowbugs), Cirripedia (barnacles), Cladocera (water fleas), Ostracoda (clam shrimp), Amphipoda (sand fleas), Copepoda (copepods), Anostraca (fairy shrimp)

3. Uniramia

* Allied phyla: Onychophora (velvet worms) which have segmented nephridia and unjointed legs, and Tardigrada (water bears) which are microscopic
* Subphyla Myriapoda

* Class Chilopoda (centipedes) one pr. legs per segment, carnivorous
* Class Diploda (millipedes) two pr. legs per segment, herbivorous

* Subphyla Insecta: chitinous, 3 segments and 3 segments in thorax, 1 pr. antennae, compound eyes (mostly), wings (mostly) attached to thorax, varied metamorphic patterns

* Class Apterygota: ancestral state wingless
* Class Pterygota: winged, with some loss of flight
 

3. Trilobita: extinct
 

ANIMAL LAB 3: ANNELIDS AND ARTHROPODS
* Understand the difference between protostomes and deuterostomes.
* Review the meaning of acoelomates, pseudocoelomates, and coelomates.
* Know the difference between schizocoelous and enterocoelous.
* In lab, we examined the internal anatomy of an earthworm.  Briefly explain how blood moves through the body of an earthworm.  What type of circulatory system is found in earthworms, i.e., open or closed?  What is the function of the crop and gizzard?
* Compare/contrast leeches and earthworms.
* There are certain features shared with all arthropods.  Describe several of these features.
* What two characteristics are present in all arachnids?
* What are book lungs?
* What is a cephalothorax?
* What distinct feature separates crustaceans from all other arthropods?
* What are chelipeds and what are they used for?
* How is sex determined in crayfish?
* In lab, you did some hypothesis testing on crayfish.  Be able to explain specifically what you tested and describe the outcomes.
* Compare and contrast centipedes with millipedes.
* There are several external characteristics displayed in insects.  Be able to name at least five.
* Explain how gases are exchanged in insects.
* What are malpighian tubes?
* Be able to explain the following terms:  ametabolous, hemimetabolous, and holometabolous.
* Name the two major classes of insects and know the specific characteristic that separates them.
* Be able to match the following organisms we examined in class with their appropriate phylum/subphylum and/or class:
 
 

Spiders/scorpians/mites
Centipedes/Millipedes
Earthworms
Crayfish
Leeches
Grasshoppers/butterflies/beetles/dragonflies/flies

Oligiochaeta (Phylum ? Annelida)
Hirudinea (Phylum ? Annelida)
Arachnida (Phylum ? Chelicerata)
Insecta (Phylum ? Uniramia)
Decapoda (Phylum ? Crustacea)
Myriapoda (Phylum ? Uniramia)
 

* Which phylum exhibits the largest number of animals?