Phylum Porifera ​and Phylum Cnidaria

Phylum Porifera

Attached is a photo was taken of Commerical Sponge Fibers that would clean your dishes with!

Magnification: 10 x .25 magnification

The function of sponge fibers is to help transport nutrients. In addition, they are part of the sponge’s exoskeleton and maintain the structure of the organism.

Types of sponges :

Rope Sponge :

Location of picture: Turks and Caicos
Common name: Scattered Pore Rope Sponge
Scientific name: Aplysina fulva

Tube Sponge :

Location of picture : Turks and Caicos
Common name : Yellow Tube Sponge
Scientific name :Aplysina fistularis

Barrel Sponge:

Location of picture : Turks and Caicos
Common name: Netted Barrel Sponge
Scientific name: Verongula gigantea

Similarities among the listed sponges :

The first major difference that can be seen among all three of the sponges is that each has a certain type of structure. These specialized structures allow each species to filter feed at the rate that best fits each organism. The three types of sponge structures are asconoid, syconoid, and leuconoid. The similarites would be these sponges though may vary in struture feed the same way all of these organisms filter feed by letting water in via pores tehn sucking the nutriets out and expelling the excess water out of the tubes.

Why are sponges brightly colored?

Simply based on the diet of what is being sucked out of the water these sponges show the bright colors as the by-product of the cyanobacteria, bacteria, and plankton they consume.

Phylum Cnidaria

Attached is a photo of an Obelia or a Hydrozoan. These are microorganisms that latch onto solid surfaces in marine ecosystems to feed, reproduce, and survive. They have no brain but posses a nerve system, digestive system, and defense mechanisms.

Specimen : Obelia
Magnification : 10 x .25

The two attached images of Hydra that are “budding” which is a term used to describe the process of how these animals reproduce.

Magnification : 10 x .25
Here we have this specimen of hydra showing stage 5 as this appears to be a new daughter that just was produced from a parent hydra.
Magnification 10 x .25
Here we will see a step 1-3 possibility of a parent hydra budding an offspring

Stages of “hydra budding”

Source of image :

1. Non-reproducing
2. Creating a bud
3. Daughter growing out
4. Beginning to cleave
5. Daughter broken off
6. Daughter clone of the parent

Follow up questions:

Cnidarians come in Polyp and/or Medusa forms what’s the difference ? :

Polyp as adults are sessile and do not move at all ex. sea anemone. In addition, they tend to be in colines sharing one parental stock. Whereas Medusa’s are mobile as adults ex. Jellyfish. These organisms tend to self established and do not share a common parent such as polyps. But some organisms in the phylum shared both these cycles during their lives ex. Portuguese man of war. These organisms share both characteristics of having polys but also colonized to be not sessile and use one another in every move.

How is Obelia different from Hydra?

Hydra Obelia

Hydra are freshwater coelenterates. Structurally like are elongated and have stalk like tubes.

In addition, Hydras are only found in freshwater environments.

Tend to be isolated but exist also in colonies.

Sessile organisms.

Obelia are sedentary organisms. They are also colonial coelenterates that are upright branching stems.

This organism lives in both freshwater and salt water environments

Exists in colonies in the wild.

Both sessile and mobile.

Structurally they posses branching stems and have minute cups that hold polyps.

What does colonial mean to a hydrozoan?

I mean that multiple organisms work together symbiotically in order to establish in a way one organism that is controlled by every single respected organism.

The Life cycle of the Obelia

Specimen : Hydromedusae (Comb Jelly)
Magnification : 10 x.25

This comb jelly is in adulthood it is translucent in appearance and small rounded in shape.

Life Cycle of an Obelia and reproduction took through step by step with each transition labeled. Check out this fellow bloggers post to get the full run down and the source of this image here.

Portuguese man of war

Source : picture of Jelly fish

How is this organism not just one but many organisms that come together to form one thing?

The polyps that form this organism work together in order to survive. They do this by coming together just as a school of fish comes together to decrease predation. As one the polyps would have a decreased fitness but together as one floating among other Portuguese Man of War they are a presence to not be ignored. Although the polyps have no way of moving independently together they form gas sacks on the Jellyfish and are able to navigate the seas via currents, winds and using their inflation of the gas pack.

Cnidarian types

Jelly fish

Image : Taken at the Boston aquarium by myself.
Specimen : Lions mane Jelly

These jellies are found along the coasts of the US. In colder waters is their typical preference environment. They can grow to have a top dome of 6 ft and have 100 feet long tentacles.

Sea Anemone

Image : Source from myself
Specimen : Sea Anemone

The Sea Anemone is classified as a Cnidaria and are sessile in nature. They do not go through a medusa phase and are a great example of these types of individuals. The orange extended tubes are polyps that collect food for the organism.


Image Source : Source
Specimen : Hydroid

Some Hydroids are isolated individuals as shown in the image. These are organisms in the youth stage that will eventually grow and detach from the substrate becoming an adult branching off later.

The similarities/differences of all the organisms listed above


Lengthy appendages

Bright color appearance

All exist within the same phylum and eat the same way.


Movement some are locked down and some are able to be mobile.

Stage of life

Hard Corals

Specimen : Bleached/ dead coral
Image: Taken by myself

What makes up these Corals?

CaCO3 (Calcium Carbonate) are what make up almost all corals. The preparations that you seem on the coral what appears to be holes are remains of what used to be polyps. Once the corals started to die these polyps release themselves and are free while their host (this coral) dies.

Different types of Coral

There are over 2,500 different species of coral that live on our planet!


Specimen : Annella mollis
Image : Taken by myself

Soft Corals

Specimen: Mushroom Leather Coral ( Sarcophyton spp)
Image : Courtesy of Reef Guide

Black Coral

Specimen: Hawaiian Black Coral (Antipathes griggi)
Image: Courtesy of Reef Guide

Stony Corals

Specimen: Common Mushroom Coral (Fungia fungites)
Image: Courtesy of Reef Guide

Similarities of the coral types

All contain polyps that can be seen on the branching surfaces of these corals. All show bright vivid colors from the feeding on zooplankton and phytoplankton. Compared to the dead specimen in the first image, one can see how important the polyps are to these organisms.

Zooxanthellae and the mutualistic relationship they share with coral.

What is a Zooxanthellae?

Defined by the dictionary a Zooxanthellae are a: “yellowish-brown symbiotic dinoflagellate present in large numbers in the cytoplasm of many marine invertebrates.

What benefits do these Zooxanthellae have for corals?

These Zooxanthellae exist in the tissue of corals and provide a mutualistic relationship with them. This relationship is conveyed by the coral giving the Zooxanthellae a place to stay keeping them safe from predators. They also provide the nutrients for them to photosynthesize as well. The Zooxanthellae then provide back to the coral’s oxygen as a by-product of there processes, amino acids, and glycerol which are all essential for corals to carry out building calcium carbonate which is the struture of the corla.

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