Porifera
What level of organization do sponges have?
What type of nervous system do cnidarians have?
A nerve net
What is cephalization?
Concentration of nerves at the anterior region (a simple head)
What type of body cavity do nematodes have?
Pseudocoelom
Why is segmentation beneficial?
Segmentation allows for more efficient movement because they can move independently from each other. And if one segment is damaged, the rest can still function/the organism won’t die.
Which cells make spicules for a sponge? And what do spicules do?
Amoebocytes
Spicules provide structural support for the sponge.
What is the function of nematocysts?
To sting and capture prey
What is the tegument?
An absorptive outer body covering/cuticle for protection
What is the advantage of having a complete digestive system?
Because food can move in one direction, allowing continuous feeding and digestion. And different parts can specialize in digestion and absorption.
What is the process by which food moves through the digestive system of an annelid?
Peristalsis
What is the function of choanocytes (collar cells)?
What type of symmetry to cnidarians have?
Why are parasitic flatworms able to survive without a digestive system?
Because the host provides nutrients and does the digesting for them.
What role do shell glands play for nematodes?
They produce a protective covering (shell) around fertilized eggs, helping them survive harsh environments.
What are the three tissue layers that flatworms, roundworms, and segmented worms have?
Endoderm, Mesoderm, Ectoderm
Why are sponges important to aquatic ecosystems?
To filter the water/improve water quality
What is the main difference between the polyp and medusa forms?
Polyps are sessile
Medusa are motile
What does hermaphrodite mean?
An organism that has both male and female gametes (reproductive parts)
What type of symmetry do nematodes have?
Bilateral
What type of skeleton do annelids have?
Describe how a sponge feeds
Filter feeding; water flows in through pores (ostia), collar cells create a current that sucks water in and traps particles, the trapped food is ingested by the cells, and after the water along with waste products is pushed out through the osculum.
How does food enter and leave the body? (# of openings)
Through the mouth, same (1) opening
Why is having hooks and suckers beneficial adaptations for parasitic worms?
Because they allow them to attach to host tissues so that they can remain in the body and not be swept away in a digestive tract.
Are nematodes hermaphrodites or dioecious?
Dioecious (separate sexes)
What is the 'small brain' that all 3 worm phylums have called and what are they attached to?
Ganglion attached to ventral nerve cords
What type of symmetry do sponges have?
None - asymmetrical
What is one advantage of sessile life for a cnidarian?
They can avoid drifting away because they are attached to a surface.
Why is diffusion still sufficient for flatworms?
Because they have a thin body and low metabolic demands (high surface area:volume ratio)
Why do nematodes move in a side-to-side motion?
Because they only have longitudinal muscles.
What type of circulatory system do annelids have?
Closed circulatory sysem - blood is contained within vessels