Porifera and Cnidaria – Flashcards
Unlock all answers in this set
Unlock answersquestion
How do sponges obtain their nutrients.
answer
Sponges are filter feeders: They filter out food particles suspended in the surrounding water as they draw it through their body, which in some species resembles a sac perforated with pores.
question
What is the name of the central cavity and what is its function?
answer
Water is drawn through the pores into a central cavity, the spongocoel.
question
How does water leave the sponge?
answer
Water flows out of the sponge through a larger opening called the osculum
question
What sets sponges apart from the rest of the animal kingdom?
answer
Unlike nearly all other animals, sponges lack true tissues, groups of similar cells that act as a functional unit and (in animals) are isolated from other tissues by membranous layers.
question
Do Sponges have specialized cells?
answer
yes, sponges have several different specialized cells.
question
What is the role of a Choanocyte?
answer
choanocytes, or collar
cells (named for the finger-like projections that form a "collar" around the flagellum). These cells engulf bacteria and other food particles by phagocytosis.
question
What is the layer that separates the bilayer of the sponge?
answer
The body of a sponge consists of two layers of cells separated by a gelatinous region called the mesohyl
question
What is a distinct feature of a amoebocyte, and name one fucntion of the cell?
answer
amoebocytes, named for their use of pseudopodia. These cells move through the mesohyl and have many functions. For example, they take up food from the surrounding water and from choanocytes, digest it, and carry nutrients to other cells.
question
What is remarkable about ameobocytes, and how are they similar to stem cells?
answer
Finally, and perhaps most importantly, amoebocytes are totipotent (capable of becoming other types of sponge cells). This gives the sponge body remarkable flex- ibility, enabling it to adjust its shape in response to changes in its physical environment
question
Do sponges have a gender, Do they reproduce sexually?
answer
Most sponges are hermaphrodites, meaning that each individual functions as both male and female in sexual reproduction by producing sperm and eggs.
question
How does cross fertilization occur? What is the relusting product?
answer
Cross-fertilization can result when sperm released into the water current by an individual functioning as a male is drawn into a neighboring individual that is functioning as a female. The result- ing zygotes develop into flagellated, swimming larvae that disperse from the parent sponge.
question
What are some examples of Cnidarians?
answer
Cnidarians have diversified into a wide range of sessile and motile forms, including hydras, corals, and jellies.
question
How are Cnidarians arranged anatomically?
answer
The basic body plan of a cnidarian is a sac with a central digestive compartment, the gastrovascular cavity. A
single opening to this cavity functions as both mouth and anus.
question
There are two variations on this body plan?
answer
There are two variations on this body plan: the largely sessile polyp and the more motile medusa
question
What is a polyp and what are some examples?
answer
Polyps are cylindrical forms that adhere to the substrate by the aboral end of their body (the end opposite the mouth) and extend their tentacles, waiting for prey. Examples of the polyp form include hydras and sea anemones.
question
How do polyps exert movement?
answer
Although they are primarily sedentary, many polyps can move slowly across their substrate using muscles at the aboral end of their body. When threatened by a predator, some sea anemones can detach from the substrate and "swim" by bending their body column back and forth, or thrashing their tentacles.
question
What is a Medusa, and what animals exhibit these traits?
answer
A medusa (plural, medusae) resembles a flattened, mouth-down version of the polyp. It moves freely in the water by a combination of passive drifting and contractions of its bell-shaped body. Medusa include free-swimming jellies. The tentacles of a jelly dangle from the oral surface, which points downward.
question
Do all Cnidarians have both plans or only one body plan
answer
Some cnidarians exist only as polyps or only as medusae; others have both a polyp stage and a medusa stage in their life cycle.
question
What feature is unique to the Cnidarians, and act as a prey and defense mechanism?
answer
The tentacles are armed with batteries of cnidocytes, cells unique to cnidarians that function in defense and prey capture
question
What are the cells that contain a stinging threat used to kill a Cnidarians prey?
answer
nematocysts contain a stinging thread that can penetrate the body wall of the cnidarian's prey. Other kinds of cnidae have long threads that stick to or entangle small prey that bump into the cnidarian's tentacles.
question
How is the nervous system of the Cnidarian organized?
answer
Movements are coordinated by a nerve net. Cnidarians have no brain, and the noncentralized nerve net is associated with sensory structures distributed around the body allowing it to react instantly.
question
How does part the poly stage resemble a colony?
answer
The polyp stage, a colony of interconnected polyps in the case of Obelia, is more conspicuous than the medusa.
question
How are hydras unusual to the rest of the Cnidarians?
answer
Hydras, among the few cnidarians found in fresh water, are also unusual hydrozoans in that they exist only in polyp form.
question
What is the clade Medusozoa?
answer
All cnidarians that produce a medusa are members of clade Medusozoa, a group that includes the scyphozoans (jellies) and cubozoans (box jellies)
question
How do the Medusozoa reproduce?
answer
1) A colony of interconnected polyps (inset, LM) results from asexual reproduction by budding.
2)Some of the colony's polyps, equipped with tentacles, are specialized for feeding.
3)3Other polyps, specialized for reproduction, lack tentacles and produce tiny medusae by asexual budding.
4)Medusae swim off, grow, and reproduce sexually.
5)The zygote develops into a solid ciliated larva called a planula.
6)The planula eventually settles and develops into a new polyp.
question
spicules
answer
A skeleton/ structural support system for the sponge that are used to catch prey for carnivorous sponges.
question
Cnidaria
answer
They are diploblastic, and have radial symmetry, they have a gastrovascular cavity that does circulation and waste. They have one opening that acts as both a mouth and a anus.
question
Herbavoric Cnidaria
answer
Some corals use alga to photosynthesize light. The use the protein GFP green Florissant protein in order to protect algae from uv light.
question
Rapalla
answer
Eyes that box jellyfish have to navigate.