Lab 3

Question 1

Cnidarians

Answer 1

Phylum Cnidaria includes diploblastic radially symmetrical motile and sessile organisms such as Hydra, sea anemones, jellyfish, and corals. Cnidarians are aquatic carnivores. The vast majority live in saltwater but there are some freshwater forms. All cnidarians are restricted to aquatic environments. They also all have a hydrostatic skeleton, meaning that support for the body is provided by water trapped within the gastrovascular cavity.

Question 2

Hydra

Answer 2

A very small freshwater cnidarian. Hydras are sessile polyps.

Question 3

Metridium

Answer 3

Hydras cousin, a much larger sea anemone, a sessile polyps.

Question 4

Annelids

Answer 4

The phylum Annelida is composed of triploblastic bilaterally symmetrical segmented worms which are most often found in marine environments, but species do exist in both freshwater and terrestrial habitats. (Segmentation can be identified externally by the presence of repeating rings along the length of their bodies which also give the phylum its name).

Question 5

Earthworms

Answer 5

Earthworms are typically studied as being representative of the phylum Annelida. These worms due to their soft unprotected skin, are restricted to damp terrestrial habitats. They ingest soil and digest the organic material within the soil.

Question 6

Pharynx

Answer 6

Muscular organ used to lubricate food to aid passage. Mainly pumps soil/food.

Question 7

Esophagus

Answer 7

Tube-like structure that transports from pharynx to crop

Question 8

Crop

Answer 8

Storage organ that temporarily holds the food.

Question 9

Gizzard

Answer 9

Grinds the food to aid in digestion

Question 10

Intestine

Answer 10

Takes the broken down food and transports it as its digested.

Question 11

Structures involved in earthworm internal transport

Answer 11

Pumping vessels and dorsal blood vessel

Question 12

Arthropods

Answer 12

Arthropods are the most successful and diverse of all animal phyla. Arthropods have exploited every possible habitat and niche and are found everywhere, from the deepest ocean depths to the hide of domesticated animals. Part of their success is due to their hard-lightweight exoskeleton and elaborately jointed appendages.

Question 13

Crayfish

Answer 13

The crayfish possesses the typical arthropod characteristics mentioned above, a chitinous exoskeleton and jointed appendages. They also have much in common with the earthworm examined earlier such as, being triploblastic, bilaterally symmetrical, cephalized and segmented.