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Notes - Porifera and Cnideria

- Animals exist on every continent on the planet. Most people consider animals to be the most

important kingdom as we are considered animals. But, what is an animal? What characteristics

define an animal?

- Animals are considered to be any _________________, ________________, ______________

without cell walls. Animals have developed a ”division of labour” to better survive. That is, they have

developed _____________ ____________ that take care of a particular function for the

organism. Ex. –

- All organisms have some symmetry to their body plan. The more specialised tissues and organs an

organism has the more likely it will move from ____________ __________ to bilateral symmetry.

- Also, as animals become more complex they tend to undergo cephalisation. _______________ is the

gathering of nerve cells and ________ ________ into their anterior end (_______). A gathering

of nerves is called a ganglion and in the case of large gathering this is called a __________.

- All animals have 7 primary functions they carryout for survival. They are:

1.) __________ – the acquisition of nutrient. Often through a mouth that leads to a digestive

gut. Feeding takes many forms like carnivorous, herbivorous, parasitic, filter feeders, and

_______________ ____________.

2.) Respiration –

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3.) Internal transport – the movement of ___________, _____________, __________

___________ etc. to cells deep inside of the organism. This is often done by a

______________ ______________.

4.) Excretion – the expulsion of toxins (____________) and waste products (_____________).

5.) Response –

6.) Movement – move throughout environment to gather nutrients, ______________, and avoid

_____________. A skeletal system and muscles are needed in most cases.

7.) ____________ – continue species by passing on _________. Can occur sexually or asexually.

Phylum Porifera

- Porifera – _______ _________ – this phylum includes both marine and fresh water sponges.

Sponges are the only animals with no specialised systems like organs. Sponges have a simple body

plan. They are essentially built like a sieve or ____________. They function to pull water through

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their millions of _______ (small holes through their epidermal layer) into their central cavity, using

tiny ______________ that beat back and forth. The flagellum are attached to special cells called

collar cells, that are ___________, and function to pull ________ _______ ____________ out

of the water and engulf them for digestion. The water exits the sponge through the ___________.

The sponge maintains its structure through an internal skeleton made of spicules and/or ________.

The spicules are created of calcium carbonate (______), or silicon dioxide (_____) by the

amebocyte cells. The flow of water serves as the respirator, excretory, and _____________

______________ for the sponge.

- Sponges reproduce both asexually and sexually. ____________ reproduction can occur through

_____________ or budding. Gemmules occur during unfavourable conditions. The sponge will

produce a small _________ shaped collection of amebocytes surrounded by ___________. This

body is very resilient to cold temperatures and _____________. It can grow into a sponge when

conditions improve. Budding occurs when a piece is broken off and simply grows into another sponge.

- Sexual reproduction occurs by sperm being released (male sponge) and carried out the osculum. If

they reach a female sponge they will be taken up by the _____________ cells and delivered to the

eggs. The zygote that develops into the larva, swims away to settle and grow into a new sponge.

_________

_____

______

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Role in Nature

- Sponges often form symbiotic relationships with photosynthetic bacteria in return for protection.

Sponges help breakdown and release minerals from shells as well as filter water. Humans have used

sponges for bathing since the ancient Romans as well as produce chemicals that are antibacterial.

Phylum ____________

- Cnidaria – _________ ________ – are soft-bodied animals with stinging tentacles around their

__________. This phylum includes jellyfish, anemones, and __________. All cnidaria have radial

symmetry and specialised tissues. Most cnidaria have a 2 stage life cycle like many plants do. The

cnidaria alternate between a ____________ polyp and a motile ____________.

- Both stages have a gastrovascular cavity for _____________ of food. They also both have a 3

layered body wall consisting of the epidermis, ___________, and the _______________.

- Cnidarians feed by stinging their prey with nematocysts. Nematocysts are a specialised cell that

functions like a ____________. The nematocyst contains a small barb that is triggered by a

specialised hair (when touched) and injects deadly toxin to stun their prey. Once stunned the prey

is pushed into the __________________ cavity for digestion. Once digested the nutrients move

into cells through __________________.

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- No central nervous system or ___________ exists, but they do have a nerve net concentrated

around the mouth. There are some cells in the epidermis for sensing touch, as well as the

_________ has very simple sense organs formed of _______________ and ocelli cells.

- Waste removal occurs through ____________ as the cnidaria are only a few cells thick.

- For _______________ the cnidaria uses specialised epidermal cells that can change shape when

stimulated. This allows movement without ________________.

- Reproduction occurs sexually and asexually. _______________ occurs by budding or having entire

medusa bud off. Sexual reproduction occurs when medusa release sperm/egg into the water which

grows into a ___________ when fertilised. The zygote will become a larva, which can swim, and will

move to a new area to settle, ____________, and grow into a polyp.

- There are three classes of cnidaria: Hydrozoa, Scyphozoan, and Anthozoa.

- ________________ – includes fresh water hydra and _______________ __________________

(not a true jellyfish as it is a colony of polyps working together). Most hydrozoa are ___________

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and have a very short medusa life stage. Most organisms have separate male and female but a few

are _____________________ (have both male and female reproductive organs).

- Scyphozoa – ____________ ___________ ____________. This class functions oppositely in that

the medusa is long lived and the polyp is very short in duration.

- Anthosoa – includes the anemones and __________. This class has NO medusa stage of life. Eggs

and sperm are released from the polyp, develop into a ciliated larva that attaches and grows into

another polyp. Anemones have a symbiotic relationship with many photosynthetic protists that live

in their cells. As such they need to be near the light at the surface.

Role in Nature

- Many cnidarians have symbiotic relationships with __________, fish, and other small animals. The

animals live amongst the tentacles for protection and feed scraps to the cnidaria in return. Coral

reefs are an integral part of housing and protection for small sea creatures while also protecting

coast lines from wave erosion. Jewelry and medicines are also very important uses for man.