ZOL1501
ANIMAL DIVERSITY I
PAST MEMOS
, QUESTION 1 [10]
Explain what is meant by each of the following terms:
1.1 Monophyletic group
1.2 Parthenogenesis
1.3 Metamerism
1.4 Epitoke
1.5 Peritonium
QUESTION 1 (10)
a. Monophyletic group is a group that includes the most recent common ancestor of a
group of organisms, and all of its descendants.
b. Parthenogenesis is a unisexual reproduction involving the reproduction of young by
females not fertilized by males.
c. Metamerism is a condition of being composed of serially repeated parts (metameres).
Serial segmentation. Metamerism is a division of the body into discrete segments or
metameres.
d. Epitoke posterior part of a marine polychaete when swollen with developing gonads
during the breeding season.
e. Peritoneum is the membrane that lines the coelom and covers the coelomic viscera.
QUESTION 2 [16]
2.1 Define the concepts “encystment” and “excystment” and explain why the phenomena
have advantages for protozoa.
QUESTION 2 (16)
2.1 Encystment is a process of cyst formation. Dormant forms marked by resistant
external cover and a complete shutdown of metabolic machinery. This process of
escape from a cyst, a stage in the life cycle of parasites occurring after the cystic form
has been ingested by the host organism. Cyst formation is important to parasitic forms
that that must survive a harsh environment between hosts. Such harsh conditions
include food deficiency, desiccation, increased environmental osmotic pressure,
decrease oxygen concentration, and a change in pH or temperature. Encystment in the
protozoan is enclosed in or as if in a cyst, thick membrane, or shell. Excystment is the
escape from cysts, a return of favourable conditions initiates excystment for those
protozoa in which the cysts are resistant stage.
2.2 Give a detailed description of the different kinds of pseudopodia encountered in
protozoa.
ANIMAL DIVERSITY I
PAST MEMOS
, QUESTION 1 [10]
Explain what is meant by each of the following terms:
1.1 Monophyletic group
1.2 Parthenogenesis
1.3 Metamerism
1.4 Epitoke
1.5 Peritonium
QUESTION 1 (10)
a. Monophyletic group is a group that includes the most recent common ancestor of a
group of organisms, and all of its descendants.
b. Parthenogenesis is a unisexual reproduction involving the reproduction of young by
females not fertilized by males.
c. Metamerism is a condition of being composed of serially repeated parts (metameres).
Serial segmentation. Metamerism is a division of the body into discrete segments or
metameres.
d. Epitoke posterior part of a marine polychaete when swollen with developing gonads
during the breeding season.
e. Peritoneum is the membrane that lines the coelom and covers the coelomic viscera.
QUESTION 2 [16]
2.1 Define the concepts “encystment” and “excystment” and explain why the phenomena
have advantages for protozoa.
QUESTION 2 (16)
2.1 Encystment is a process of cyst formation. Dormant forms marked by resistant
external cover and a complete shutdown of metabolic machinery. This process of
escape from a cyst, a stage in the life cycle of parasites occurring after the cystic form
has been ingested by the host organism. Cyst formation is important to parasitic forms
that that must survive a harsh environment between hosts. Such harsh conditions
include food deficiency, desiccation, increased environmental osmotic pressure,
decrease oxygen concentration, and a change in pH or temperature. Encystment in the
protozoan is enclosed in or as if in a cyst, thick membrane, or shell. Excystment is the
escape from cysts, a return of favourable conditions initiates excystment for those
protozoa in which the cysts are resistant stage.
2.2 Give a detailed description of the different kinds of pseudopodia encountered in
protozoa.
