Kingdom Animalia: Phyla Porifera and Cnidaria 2015/Lab_Animalia...1 Kingdom Animalia: Phyla Porifera...

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1 Kingdom Animalia: Phyla Porifera and Cnidaria Essential Question(s): What are key characteristics to the animal kingdom? Objectives: 1. Students will be able to distinguish essential characteristics in the animal kingdom. 2. Students will be able to differentiate between phyla of the animal kingdom 3. Student will recognize defining attributes in the Porifera and Cnidaria phylas. In the following chart are the listed traits of animals and associated new vocabulary. Examine the chart below and new vocabulary. Kingdom Animalia Cell Feature Eukaryotic, no chloroplast present, small cells Body Plan Multicellular, Highly differentiated, Motile, Blastula, Gastrulation Nutrition Heterotrophic, may be predators or parasites. Life Cycle Haploid (sperm and egg) and diploid(multicellular) phase Introduction: Animals originated in the oceans of the Precambrian era about 1.5 billion years ago. The first animals were multicellular, eukaryotic and heterotrophic. They were the first “predators.” By the beginning of the Cambrian period (543 mya), sponges and cnidarians were already present. During the end of the Precambrian and the beginning of the Cambrian, a huge diversification of the animals took place. This is called the Cambrian Explosion, although it spanned the Cambrian-Precambrian boundary (565 to 525 mya). Most extant phyla are directly traced to this period. During this period, animal phyla displayed dramatic variation in tissue formation, body symmetry, gut tube formation, major feeding structures, molting strategies and skeletal arrangements. These evolutionary trends, through natural selection, resulted in the major animal lineages of today. In this particular lab we will study the first two phyla, Porifera and Cnidaria.

Transcript of Kingdom Animalia: Phyla Porifera and Cnidaria 2015/Lab_Animalia...1 Kingdom Animalia: Phyla Porifera...

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Kingdom Animalia: Phyla Porifera and Cnidaria

Essential Question(s): What are key characteristics to the animal kingdom?

Objectives:

1. Students will be able to distinguish essential characteristics in the animal kingdom.

2. Students will be able to differentiate between phyla of the animal kingdom

3. Student will recognize defining attributes in the Porifera and Cnidaria phylas.

In the following chart are the listed traits of animals and associated new vocabulary. Examine the

chart below and new vocabulary.

Kingdom Animalia

Cell

Feature

Eukaryotic, no chloroplast present, small cells

Body Plan Multicellular, Highly differentiated, Motile, Blastula, Gastrulation

Nutrition Heterotrophic, may be predators or parasites.

Life Cycle Haploid (sperm and egg) and diploid(multicellular) phase

Introduction:

Animals originated in the oceans of the Precambrian era about 1.5 billion years ago. The first animals

were multicellular, eukaryotic and heterotrophic. They were the first “predators.” By the beginning

of the Cambrian period (543 mya), sponges and cnidarians were already present. During the end of

the Precambrian and the beginning of the Cambrian, a huge diversification of the animals took place.

This is called the Cambrian Explosion, although it spanned the Cambrian-Precambrian boundary

(565 to 525 mya). Most extant phyla are directly traced to this period. During this period, animal

phyla displayed dramatic variation in tissue formation, body symmetry, gut tube formation, major

feeding structures, molting strategies and skeletal arrangements. These evolutionary trends, through

natural selection, resulted in the major animal lineages of today. In this particular lab we will study

the first two phyla, Porifera and Cnidaria.

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Figure 2: Sea Sponge labeled diagram.

Figure 1: Sea-anemone (cnidarian)

illustration showing radial symmetry

Three essential characteristics to observe while progressing through each animal phyla are symmetry,

cephalization, and body cavity. There are two types of symmetry present in animals, bilateral like

humans, and radially symmetrical like a wheel.

As the exception, sponges do not exhibit any type of symmetry.

Cephalization, having a head, only occurs in bilaterally

symmetrical animals where the brain and most of its sensory

organs are located. Throughout this lab you will observe

acephalic organisms and one cephalic organism. Body cavity

refers to having an area where digestive and other internal

organs form and reside. Though Poriferans and Cnidarians do

not have body cavities they will be included in the next animal

specimens to be observed.

Phylum Porifera

The basic body form of all sponges is a sac-like

structure consisting of three sections, outer-most

epidermal cells and aggregations of specialized

cells beneath them, such as flagellated cells called

choanocytes; and clusters of amoeboid cells that

form skeletal structures of various sorts. These cell

groupings are perforated by a large number of

small pores and canals. The main cavity of this

sac-like arrangement is called the spongocoel and

has at least one large opening to the outside, called

an osculum. The sponges are taxonomically

classified based on the type of skeletal elements

produced.

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Figure 3: 1=Porifera body structure. Colour-coding: *Yellow: pinacocytes *Red: choanocytes *Grey: mesohyl * Pale

blue: water flow Structure types: *Left: asconoid *Middle: syconoid *Right: leuconoid Re

These include calcareous spicules, siliceous spicules, or proteinaceous spongin fibers. This leads to

the basic sponge taxonomy, which includes three classes.

Sponges in the Class Calcarea have calcium carbonate spicules, which have three or four rays. All of

these sponges are marine. The Class Hexactinellida have siliceous spicules, which are 6 rayed. These

sponges are all marine and most often cylindrical in form and found in deep water. The Class

Demospongiae are typically called “bath sponges” because they are used by humans for bathing. These

sponges have spongin fibers, or siliceous spicules, or both. They represent over 90% of the sponges in

the world, and one family is found in fresh water.

In all sponge types, the body is designed to facilitate filter-feeding. Water is pulled into the pores and

canals by the beating of the flagella of choanocytes. The water moves into the spongocoel and is

eventually forced out through the osculum. As the water passes across the choanocytes, food

particles (microscopic algae, bacteria, and organic debris) adhere to the cells and are eventually taken

into food vacuoles for intracellular digestion.

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Figure 5: Grantia cross section

Figure 7: Isolated Spicules

(right)

Figure 6: Spongin fibers

(left)

Figure 4: Scanning electron micrograph images of a selection of microscleres and megascleres of demosponges, not to scale, sizes vary

between 0.01 and 1 mm.

Observe:

1) Obtain a preserved specimen of Grantia, look closely and try to see how their bodies are designed

to move water in order to feed and move water.

a. Are any of the features observed in Grantia those of an animal? Explain.

2) Examine a slide of a Grantia cross-section. Pay close

attention to the folded body wall.

a. Draw your observation indicating the external environment and the

Spongocoel.

b. Label choanocytes and amoebocytes from your previous drawing.

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3. Examine a prepared slide of sponge fibers. These are the commercial sponges.

Cnidaria:

Members of the largely marine Phylum Cnidaria are considered to be more "advanced" than the

poriferans for two major reasons. First, they are the first animal to show multicellular layers, i.e.

tissue level organization, although they have no organs. Second, the adult forms are derived from

two distinct embryonic germ layers, the ectoderm and the endoderm hence, they are diploblastic.

Higher phyla are triploblastic (derived from three distinct embryonic germ layers). The organisms in

the phylum Cnidaria are characterized by radial symmetry. Terms for direction use the mouth as a

point of reference. The end of the organism which contains the mouth is oral; the opposite end of the

animal is aboral. Radial symmetry refers to the fact that any plane passing through the oral-aboral

axis divides the animal into two equal halves, or that the body tends to radiate out from the oral-

aboral axis like spokes of a wheel.

The basic body plan of the cnidarians is a sac-like structure, with a gastrovascular cavity. The

gastrovascular cavity has a single opening which serves as both mouth and anus; it is often

surrounded by tentacles. The body wall has an external cell layer, the epidermis; an internal cell

layer, the gastrodermis that lines the gastrovascular cavity; and a jelly-like layer between these two,

called the mesoglea which may be either cellular, or more often, acellular. Unique cellular

components, called nematocysts are found in cells called cnidocytes. Cnidocytes (hence the phylum

name Cnidaria) are especially abundant on tentacles, but may be generally distributed throughout

the epidermis and gastrodermis.

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Figure 8. Diagram of a cross section of a jellyfish (Olindias formosa) showing the main parts of a jellyfish

The life cycle of a typical cnidarian alternates between an often sessile polyp stage and a free-

swimming medusa stage. The existence of two distinct forms such as this is known as developmental

polymorphism. Both stages exhibit the radial body plan described above; however, the polyp stage is

cylindrical and attached at the aboral end to a substrate, while the medusa stage is flattened or

domed in appearance with the mouth oriented downward. In Scyphozoans the polyp is an asexual

stage, while the medusa is a sexual stage. In some Cnidarian classes, either the polyp or the medusa

stage may be reduced or completely absent (e.g. Hydra). You will examine the three classes of the

Phylum Cnidaria: Class Hydrozoa, Class Scyphozoa, and Class Anthozoa.

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Figure 9: Hydra budding 4X

Summary characteristics of class Hydrozoa and specific specimens.

Class Hydrozoa Specimen 1 :

Hydra

Specime 2:

Obelia

Specimen 3:

Physalia

Specimen 4:

Ganoneimus

*Dominant Polyp

stage *Germ layers

are separated by

acellular mesoglea

*Ectodermal cells

have cnidocytes and

muscular contractile

cells *Endodermal

cells secrete

enzymes for

digestion

*Small * lives

in shallow

freshwater

*Prey on

smaller

invertebrates

*Do not have

medusa stage

*Has colonial

polyps

*Polymorphic

polyps

*Gastroid

polyps are for

feeding

*Gonozoid

polyps are for

reproduction.

*Floating

polymorphic

colony of polyps

*Gas filled polyps

for floatation

*Nutritive polyps

make up long

tentacles

*Tentacles are

lethal for small

fish

*Large

medusae

*Gonads

attach to

radial canals

and appear

similar in

males and

females

*Tentacles

have a rough

surface

Observe:

1) Obtain a live Hydra sample. Allow a few minutes for specimen to relax in petri dish and then

observe under a dissecting microscope.

2) Tap the edge of petri dish and observe behavior of Hydra. Place live Daphnia near Hydra tentacles.

a. Describe your observations.

b. What tissues must exist for the behaviors observed?

3) Examine prepared slides of budding hydras and a cross section of hydra showing

endoderm and ectoderm.

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3) Under a microscope examine prepared slide of both polyp and medusae of Obelia.

Differentiate a feeding polyp from a reproductive polyp.

4) Examine preserved sample of Gonionemus,

Class Scyphozoa

Commonly called the jellies are the Aurelia and Cassiopeia. The planula is the

typical larva of a cnidarian. After sexual reproduction, this larva is formed; it

swims to a new location and develops into a polyp or medusa. The gelatinous

medusa is the dominant body form in the life cycle of Schyphozoans.

Class Anthozoa: Corals

Corals are colonial cnidarians, often having huge numbers of polyps. They

have internal skeletons, which you see here. You should be able to see the small holes where the polyps

lived. When the coral was alive, the entire skeleton was covered by a skin of living tissue. These corals

made their living mostly by symbiosis with photosynthetic zooxanthellae, a type of dinoflagellate

(Protista)

Figure 10: Obelia 4X Figure 12: Physalia Tentacle Figure11: Obelia Medusae 40X

Figure 13: Jelly cc10

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Figure 15: Planaria Body plan

Observe:

1) Examine anthozoans on display.

a. How does the feeding method of a sponge compare with that of a coral?

Introduction to the Flatworms:

Phylum Platyhelminthes Flatworms. The acoelomates

are animals that lack a coelom. Acoelomates lack a

body cavity, and instead the space between the body

wall and the digestive tract is filled with muscle fibers

and loose tissue called parenchyma. These animals

possess three living cell layers (i.e.: ectoderm,

mesoderm, and endoderm) which makes them

triploblastic. The Platyhelminthes, or flatworms are

an economically important group because they

include the parasitic tapeworms and flukes, which

affect both humans and the livestock we depend on.

These acoelomates are advanced over other radiate animals in several ways. 1. Their bilateral

symmetry adapts them for direct movement. 2. Their tissues are well defined and organized into

complex organs. 3. The nervous system is organized and concentrated in the anterior end of the

animal (cephalization). 4. They do not depend on simple diffusion for elimination of nitrogenous

wastes, but have an

excretory system based on

structures called flame

cells.5. They possess a

complex digestive tract

with both a mouth and

anus.

Figure 14: Coral Polyp anatomy

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Figure 16: Planaria digestive tract 4X

Class Turbellaria (Planarians)

Planarians are found on the underside of stones and submerged leaves or sticks in freshwater springs

and ponds. They are often confused with leeches, which they resemble in size, shape and color.

Unlike leeches planarians are not segmented and usually do not resort to blood meals.

Slides of stained Turbellaria

(Planaria)

View slides of stained whole mount of

planaria. Sketch and label the digestive

system in your preparation.

Observation of live Planarians

Gently, using forceps, an eyedropper or a finger, place a live planarian in a petri dish with the

spring water provided. Periodically replace the water as it evaporates.

External Structures:

Observe the animal and decide which is the anterior, posterior, dorsal and ventral surface.

On your live specimen note the ear-like auricles. These structures bear sensory cells but they are

tactile neither auditory nor olfactory. Note the eyes, do they possess lenses?

Locomotion:

Note how your specimen moves across the petri dish. This gliding movement is accomplished in part

by mucus on which the planarian moves via cilia. The body is also propelled by waves of muscle

contractions. Note how the animal will shorten and lengthen its body length to accomplish

movement.

11 Figure 18. An adult tapeworm.

Reactions to Stimuli:

Observe the responses of planarians to touch (thigmotaxis) and light (phototaxis) through the

following experiments: - Response to touch. Very gently touch the outer edges of the worm with a

probe or pencil. Which parts of the body are the most sensitive? - Response to directional

illumination. Direct a strong light at the planarians from one side of the dish and observe their

movements. Periodically, move the dish around the light pausing to note the animal's response. Is the

response random or directional?

Class Trematoda (Flukes)

All trematodes are parasitic, harbored in or on a

great variety of animals. Many have two

intermediate hosts before reaching the final host.

Examine a slide of Schisistosom

jamonicum. An odd feature of this genus is

the strong sexual dimorphism. The males are

stouter than the females and have a longitudinal

groove called the gynecophoric canal. Even odder,

the thinner female normally resides there,

permanently embraced by the male. Note the

strong oral sucker and secondary sucker near the

anterior end.

Class Cestoda (Tapeworms)

Tapeworms are all endoparasitic and

show extreme adaptations to their

existence through the complete loss

of their digestive tract, and a focus

Figure 17. A fluke showing internal

anatomy.

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on reproduction. Most require a single intermediate host and a final host, where the adult tapeworm

resides. As their name implies their long bodies are usually made of segments called proglottids. As

new proglottids are formed anteriorly the older ones are pushed towards the tail, hence the most

mature proglottids are found at the posterior end. The scolex is located on the head and is used for

attachment.

Examine the preserved slides of Taenia pisiformis. Attempt several sketches of the scolex

and suckers, which are used for attachment. Sketch both mature and immature proglottids if present.

Label the structures you can discern.

Since tapeworms are hermaphroditic each proglottid contains both male and female gonads. The

mature proglottid contains a genital pore laterally (on the side). From this pore two tubes extend into

the interior. The anterior, convoluted tube, which branches in the middle of the proglottid, is the

sperm duct. It branches to the different testes in the segments. The posterior duct is the vagina, which

connects to the ovaries via the oviducts.

Planarian Regeneration Experiment:

As we learned in class planarians have incredible powers of regeneration. It's now time to make some

cuts! Now pair up with another classmate.

1. Clean razor blade or sharp scalpel

2. A clean petri dish with cover and partially filled with spring water

3. Obtain two flatworms per group

Procedure:

Using a pair of forceps, place the planarian on a piece of tissue paper and place both on a cube

of ice. The planarian will immediately extend and become catatonic.

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Place the ice, tissue paper, and planarian under a dissecting microscope and decide how you

want to cut your worms. If you decide to make longitudinal cuts make sure the cut is clean

and has completely separated the cut surfaces.

Place the cuts and cut planarians into the petri dish (with your name on the cover) and place in

a cool place. To insure the health of our specimens the water must be changed every 3 days

with fresh spring water. At each water change remove any dead pieces which will appear

fuzzy and gray.

Use the attached tables on the following page to sketch your initial cuts. At each water change

(every 3 days) examine and sketch the regeneration of new body parts.

Observe the specimens for 1 week.

Important: If you make longitudinal cuts for 2 headed worms, you will need to renew the cuts

1 and 2 days after the initial incisions. This is done to prevent the two pieces fusing back

together.

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Sources:

1. De Anza Lab Manualhttp://faculty.deanza.edu/heyerbruce/bio6a

2. Survey of the Animal Kingdom : Phyla Porifera, and Cnidaria

3. http://cfcc.edu/blogs/jrogers/files/2014/09/Phylum-Platyhelminthes.pdf

Image Sources:

Figure 1 - Sea anemone

Figure 2: Sea Sponge labeled diagram.

https://commons.wikimedia.org/wiki/File:Sea_sponge_diagram.svg#/media/File:Sea_sponge_diagra

m.svg

Figure 3: https://commons.wikimedia.org/wiki/File:Porifera_body_structures_01.png

Figure 4: Scanning electron micrograph images of a selection of microscleres and megascleres of

demosponges, not to scale, sizes vary between 0.01 and 1 mm.

https://upload.wikimedia.org/wikipedia/commons/b/ba/Demospongiae_spicule_diversity.png

Figure 8:

https://commons.wikimedia.org/wiki/File:Cross_section_jellyfish_en.svg?fastcci_from=24861

Diagram of a cross section of a jellyfish (Olindias formosa) showing the main parts of a jellyfish

Figure 13: : "Jelly cc10". Licensed under CC BY-SA 2.0 via Wikimedia Commons -

https://commons.wikimedia.org/wiki/File:Jelly_cc10.jpg#/media/File:Jelly_cc10.jpg

Figure 14: http://oceanservice.noaa.gov/education/tutorial_corals/media/supp_coral01a.html

Figure 17: http://www.phsource.us/PH/PARA/Chapter_6.htm

Fugure 18: http://pathologyoutlines.com/topic/parasitologydipylidiumcaninum.html