Invertebrate Metazoa

Question 1

What do all metazoan animals have in common?

Answer 1

Cells differentiated into specialised tissues and organs, and usually a digestive cavity.

Question 2

In what phylum do sponges belong?

Answer 2

Porifera

Question 3

In what phylum do jellyfish belong?

Answer 3

Cinidaria

Question 4

Cnidaria also include..?

Answer 4

Corals and anemones

Question 5

Name the three worm phyla and which species belongs to each.

Answer 5

Platyhelminthes (flatworms), nematodes (roundworms) and annelids (segmented worms).

Question 6

What are stromatolites

Answer 6

Earliest known fossils, build ups of cyanobacteria and sediments formed layered structures.

Question 7

The Great Oxidation Event took place when and why?

Answer 7

~2.3bya, biological activity of bacteria led to the presence of atmospheric free oxygen.

Question 8

During what geological period was the first mass extinction and what caused it?

Answer 8

Permian-Triassic, caused by volcanic eruptions

Question 9

During what geological period was the second mass extinction and what caused it?

Answer 9

Cretaceous-Tertiary, caused by meteorite impact

Question 10

What defining characteristics do invertebrates in the arthropod phylum have in common?

Answer 10

Exoskeleton, segmented body and paired jointed appendages. (E.g insects, crustaceans, arachnids)

Question 11

define tagmosis

Answer 11

grouping of segmented arthropod body-plan into regions with specialised functions e.g head, thorax, abdomen.

Question 12

How do hox genes affect the segmentation of arthropods?

Answer 12

code for different characteristics of the body-plan along the anterior posterior axis.

Question 13

Crustaceans are part of what major group belonging to the arthropoda?

Answer 13

Mandibulates

Question 14

Spiders are part of what major group belonging to the arthropoda?

Answer 14

Chelicerates

Question 15

invertebrate chordates have no backbone but they do have a nerve cord. What supportive structure do they retain in place of a spinal cord?

Answer 15

notochord - in vertebrates the embryonic notochord is lost in place of a skeleton.

Question 16

from which embryonic structure does the CNS (brain & spinal cord) develop in vertebrates that invertebrate chordates retain?

Answer 16

Dorsal hollow nerve cord

Question 17

name the 2 sub-phylums of the invertebrate chordata

Answer 17

Tunicata (or Urochordata) and Lancelets (or Cephalochordata)

Question 18

name the 3 classes within the sub-phylum Tunicata

Answer 18

Ascidians, Appendicularia (larvaceans) and Thaliacea (salps)