Section 26-3 Flashcards
Cnidarians are members of phylum ??
Cnidarians
What important features unite the cnidarians as a group?
Important features of cnidarians are soft-bodied, carnivorous animals with stinging tentacles arranged in circles around their mouths and have specialized tissues with body symmetry.
What are cnidocytes
Cnidocytes are stinging cells that are located on the cnidarians’ tentacles
A poison filled, stinging structure within a cnidocyte that contains a tightly coiled dart is called a ??
Nematocyst
Is the follow sentence true or false? Cnidarians have bilateral symmetry
False
What are the two stages in the cnidarian life cycle
a) polyp
b) medusa
Look at diagram
Polyp and Medusa
Gastroderm
Inner lining of the gastrovascular cavity
Mesoglea
Layer that lies between gastroderm and epidermis
Gastrovascular Cavity
Digestive chamber with single opening
Nerve Net
Loosely organized network of nerve cells
Statocysts
Sensory cells that help determine direction of gravity
Ocelli
Eyespots that detect light
Circle the letter of each sentence that is true about form and function in cnidarians.
A) In a polyp, the mouth points downward.
B) Materials that cannot be digested are passed out of the body through the mouth.
C) Cnidarians respire by diffusion through their body walls.
D) Most cnidarians reproduce sexually and asexually.
B, C, D
What does a cnidarian’s hydrostatic skeleton consist of?
It consists of a layer of circular muscles and a layer of longitudinal muscles, as well as the water in the gastrovascular cavity.
Cnidarian polyp can reproduce asexually by ??
Buddins
In the Aurelia life cycle, how are young medusas released?
An aurelia polyp buds to release medusas
Live lives primarily as medusas
Schohozoa - Jellyfishes
Polyps of most grow in branching colonies; some lack a medusa stage
Hydrozoa - Portuguese man-of-war and hyrdas
Have only the poly stage
Anthozoa - Corals and Sea Anemones
What’s bioluminescence
Bioluminescence is the production of light by an organism. Jellyfishes use it to ward off the predators.
How do hydras differ from other cnidarians in the class hydrozoa
They lack a medusa stage
Circle the letter of each sentence that is true about corals
A) Corals secrete an underlying skeleton of calcium carbonate.
B) Corals are solitary polyps that live at all depths of the ocean.
C) Coral colonies growing near one another produce coral reefs.
D) Most corals are colonial.
A, C, D
Is the following sentence true or false? Sea anemones are solitary polyps.
True
How are corals reefs produced?
As colonies groups grow, they secrete an underlying skeleton of calcium carbonate. Many coral colonies growing near one another do produce coral reefs.
What variables determine the worldwide distribution of corals?
temperature
water depth
light intensity
What do corals depend on to capture solar energy, recycle nutrients, and help lay down their skeletons?
They depend on symbioses with algae
Circle the letter of each way that coral reefs can be harmed
A) Sediments from logging can smother corals.
B) Overfishing can upset the ecological balance of coral reefs.
C) Algae can remove energy from corals.
D) Industrial pollutants can poison corals.
A, B, D
What is coral bleaching?
High temperatures can cause symbiotic algae to be lost from the coral tissues, leaving behind only transparent cells atop ghostly white skeletons.
