Practical #1 Exam: Porifera and Cnidaria

Question 1

What phylum do sponges fall under?

Answer 1

Porifera

Question 2

Characteristics of Portifera

Answer 2

• cellular level of organization
• multicellular
• cells don’t quite fit the definition of tissue
• filter feeding through pores and canals
• skeleton made of spicules and spongin
• have special cells lining their canals called
  choanocytes for feeding and moving water
• mutualistic (both benefiting)
  symbiotic relationship with algae
• sponges get food (glucose) from the photosynthesizing
  algae
• algae gets protection from the sponge

Question 3

Pores

Answer 3

• ostia
  -osculum

Question 4

Canals

Answer 4

• spongocoel
• radial canals

Question 5

Path of Water Through Sponges

Answer 5

Ostia → Radial Canal → Spongocoel → Osculum

Question 6

What are Choanocytes?

Answer 6

• the lining that is the inside of the sponge
• single, flagellated cells
• flagella move in the water which create water flow
• cells filter out nutrients from the water

Question 7

Types of Sponges

Answer 7

• asconoid
• syconoid
• leuconoid

Question 8

Asconoid Sponges

Answer 8

• don’t have radial canals (ostia → spongocoel → osculum).

Question 9

Synconoid Sponges

Answer 9

• have radial canals that all connect to the spongocoel

Question 10

Leuconiod

Answer 10

• have a network of canals and a very small spongocoel.

Question 11

What is the phylum for corals, anemones and jellyfish?

Answer 11

Cnidaria

Question 12

Phylum Cnidaria Characteristics

Answer 12

-radial symmetry
-tissue level of organization
-diploblastic (2 tissue layers)
-have a gastrovascular cavity
-have cnidocytes on their tentacle that contain nematocysts
-usually have 2 types of body form, polyp and medusa

Question 13

What is Diploblastic tissue?

Answer 13

• epidermis
• gastroderm

Question 14

Cnidocytes

Answer 14

cells

Question 15

Nematocysts

Answer 15

• stinging organelles
• type of cnidocyte
• covered by operculum (cover/flap)
  -triggered by cnidocil (modified cilium)
  -threadlike filament injects venom when contacts prey/threat
• once fired, cannot be reloaded
  -the cell is reabsorbed and replaced

Question 16

Polp

Answer 16

sessil body form

Question 17

Medusa

Answer 17

free swimming body form

Question 18

Class Hydrozoa Characteristics

Answer 18

• small
• usually colonial
  -have cnidocytes (stinging cells)

Question 19

What class is Aurellia (jellyfish) in?

Answer 19

Scyphozoa

Question 20

Class Scyphozoa

Answer 20

-aurelia or jellyfish
-size ranges usually from 2 to 40cm,
-most of body comp. is water
- carnivorous organisms that feed on fish and other marine vertebrates.

Question 21

What class do anemones and corals fall under?

Answer 21

Anthozoa

Question 22

What is Metridium?

Answer 22

A sea Anemone

Question 23

Class Anthozoa

Answer 23

-strictly marine animals usually found on rocks and pilings
-usually solitary, sessile animals
-can be found in colonies as well
-polp body form
-no medusae

Question 24

What is Astrangia?

Answer 24

Stony coral

Question 25

Astrangia

Answer 25

-small anemones
-usually colonial.
-some colonies consists of millions of individuals, forming coral reefs.
-shallow water coral
-feeds principally on zooplankton, which are paralyzed by nematocysyts
on its tentacles and carried to its
mouth via its cilia.

Question 26

Local sponges (freshwater)

Answer 26

-have digitiform (finger-like) growth forms
-are not very big (live in small colonies)
-latch onto rocks and sticks
-found in lakes, ponds, rivers, and streams (permanent water sources)

Question 27

Metridium Whole Specimens Anatomy

Answer 27

-sea anemone internal and external structures
-general body structure is cylindrical
-body can be divided to three sections: oral disc, cylindrical column, basal disc,
-sessile, sea anemone
can glide slowly on its basal disc

Question 28

What is oral disc?

Answer 28

tentacles and mouth

Question 29

What is cylindrical column?

Answer 29

forming of the main body

Question 30

What is basal disc?

Answer 30

attaches itself to a solid object