Lab Practical One

Question 1

During the past two labs, which Domain and which Kingdom have we been examining?

Answer 1

The Domain is Eukarya
The Kingdom is Animalia

Question 2

Name and explain the body types for the Class Phylum Porifera.

Answer 2

1. Ascon - no folding to body wall (simply a hollow tube with just a few cells) (gen. small)
2. Sycon - simple infolding to body wall (allows for larger size)
3. Leucon - much folding with series of chambers connected by canals (most sponges today)

Question 3

Explain the function of “choanocytes” in the Class Phylum Porifera.

Answer 3

1. Choanocytes - line the interior surface of radial canals and trap food particles with their flagella, which are passed on to the amoebocytes.

Another function is that the beating flagella creates water currents.

Question 4

Explain the function of “porocytes” in the Class Phylum Porifera.

Answer 4

Porocytes are tiny pores that are scattered along the folds of incurrent canals.

They channel water into the radial canals (have the flagellated choanocytes helping)

Question 5

Explain the function of “amoebocytes” in the Class Phylum Porifera.

Answer 5

Amoebocytes are mobile cells that reside between the choanocytes and pinacocytes (outer layer).

They carry food to other cells within the sponge.

They also can transform into any other cell type that the sponge may need to function properly.

Question 6

Explain the function of “pinacocytes” in the Class Phylum Porifera.

Answer 6

Pinacocytes are the cells making up the outer layer

Question 7

Explain the function of “sclerocytes” in the Class Phylum Porifera.

Answer 7

Sclerocytes secrete the skeletal elements of sponges (spicules) or (spongin)

Question 8

Describe the path of water in the Class Phylum Porifera.

Answer 8

As oxygen rich water passes through the sponge body, simple diffuses into the cells occurs (CO2 diffuses outward) (metabolic waste also diffuses out)

The oxygen-devoid water passes out each radial canal through a large opening called apopyle into the spongocoel, and is finally pushed out of the osculum.

Question 9

Name the different reproductive methods of sponges.

Answer 9

1. Regeneration
2. Fragmentation and Budding (some)
3. Formation of Gemmules (freshwater)
4. Sexually (occasionally)

Question 10

Explain Gemmules in Sponges.

Answer 10

Gemmules are dense, hardened balls that contain amoebocytes surrounded by collagen and spicules.

The rest is history.

Question 11

Briefly explain sexual reproduction in sponges.

Answer 11

Occasionally, choanocytes will lose their collars and flagella and divide meiotically to become haploid and are released into the water.

When another sponge receives them, they become embedded into a haploid egg, and the egg develops into a larva, breaks free and becomes another sponge.

Question 12

Name and explain the body forms from the Phylum Cnidaria.

Answer 12

Polyps - generally a cylindrical organism with a mouth that usually faces upward.

Medusa - generally a more circular, umbrella shaped form with a mouth on the underside, and tentacles that surround the mouth.

Question 13

Name and explain the locations the tissue layers of the Phylum Cnidaria.

Answer 13

1. Epidermis - outermost layer
2. Gastrodermis - innermost layer, which lines the central digestive cavity, the gastrovascular cavity.

Question 14

What is the mesoglea in the Phylum Cnidaria?

Answer 14

The mesoglea is the thin gelatinous layer that is between the epidermis and the gastrodermis.

Question 15

What are Cnidocytes in the Phylum Cnidaria?

Answer 15

They are the unique stinging cells that are present on the tentacles and body of members of the group.

Question 16

What is the Taxonomy of the Phylum Cnidaria?
(the three classes we learned about)

Answer 16

1. Class Hydrozoa (hydra, obelia)
2. Class Scyphozoa (jellyfish)
3. Class Anthozoa (sea anemones and coral)

Question 17

Name the tissues of the Phylum Platyhelminthes.

Answer 17

1. Epidermis - outer most layer
2. Mesoderm - middle layer (eventually differentiates into muscle (why they are the first motile animals)
3. Gastrodermis - inner most layer (to the gastrovascular cavity

Question 18

Name and explain the organ systems of the Phylum Platyhelminthes.

Answer 18

1. Rudimentary nervous system with ganglia focused on the anterior side (cephalization) and protrudes downward.
2. Gastrovascular System has a cavity with a singular opening.

While most waste is eliminated through diffusion, pouches called flame cells (in a network of tubules) to excrete.

3. Muscular System - the mesoderm tissue develops into muscles during embryonic development

Question 19

Name the three classes of the Phylum Platyhelminthes.

Answer 19

1. Turbellaria (planarians)
2. Trematoda (flukes)
3. Cestoda (tapeworms)

Question 20

Explain the habitat and feeding of the class Turbellaria in the Phylum Platyhelminthes.

Answer 20

They typically habitat freshwater streams, ponds, oceans, or even under rocks. Basically anywhere that is moist.

They are predatory and feed on small crustaceans, protists, and roundworms.

They secrete mucous from gland cells that entangle small prey and then projects its muscular pharynx through the ventral mouth and sucks like a straw.

Question 21

Explain the habitat of the Class Trematoda in the Phylum Platyhelminthes.

Answer 21

Trematoda are parasitic in that they attach to another organism (host) by means of suckers in the internal organs, such as intestines, lungs and blood vessels, bladder or liver.

Question 22

Explain the habitat and growth of the Class Cestoda of the Phylum Platyhelminthes.

Answer 22

Cestoda are parasitic and they (like the Trematoda) reside in the internal organs of other organs, and attach via suckers.

The body is a series of continuously growing segments called proglottids.

New proglottids form behind the scolex, and as they enlarge they are shifted towards the rear of the tapeworm

Question 23

Explain the habitat of the Phylum Nematoda.

Answer 23

Nematodes are free living (soil, freshwater, marine) or (parasitic)

Question 24

Explain the tissue layers of the Phylum Nematoda.

Answer 24

1. Epidermis
2. Gastrodermis
3. Mesoderm

Question 25

Explain the digestive tract of the Phylum Nematoda.

Answer 25

Nematodes have a complete digestive tract which includes two openings, a mouth and an anus.