BSC 1011 EXAM 4 QUESTIONS WITH VERIFIED ANSWERS
A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A
postdoctoral student thinks it looks more like an aquatic fungus. How can they decide
whether it is an animal or a fungus? - Answers - Look for cell walls under a microscope.
All animals can trace their lineage to a common ancestor that lived in the _____. -
Answers - Neoproterozoic era
The earliest ancestors of about half of all extant animal phyla can be traced back to the
_____ explosion. - Answers - Cambrian
Which of the following is radially symmetrical? - Answers - A doughnut
Gastrulation is the process that directly forms the _____. - Answers - Primary germ
layers
Which of the following is NOT a characteristic of all animals? - Answers - They have
tissues, organs, and organ systems.
An important trend in animal evolution was cephalization. An animal is said to show
cephalization when it _____. - Answers - has an aggregation of sensory neurons at the
anterior end.
Which of the following animals does NOT have a body cavity? - Answers - Flatworm
During embryological development, the anus forms before the mouth in _____. -
Answers - humans
Which of the following statements is correct? - Answers - All animals share a common
ancestor
An animal that can be divided along at least different planes to produce mirror images is
said to have _____. - Answers - radial symmetry
An animal that cannot be divided along any plane to produce mirror images is said to
display _____. - Answers - asymmetry
An animal that can be divided along a single plan to produce mirror images is said to
have _____. - Answers - bilateral symmetry
_____ gives rise to the lining of the digestive tract or gut - Answers - endoderm
,_____ gives rise to muscles and most other organs between the digestive tract (or gut)
and the outer covering of the animal - Answers - mesoderm
_____ gives rise to the outer covering of the animal - Answers - ectoderm
An animal with only two embryonic germ layers, such as a jelly, is called a(n) _____ -
Answers - diploblast
An animal with three embryonic germ layers, such as a reptile or insect, is called a(n)
_____ - Answers - triploblast
Some animals, such as roundworms, have an internal body cavity that is formed from
both mesoderm-derived and endoderm-derived tissues. This type of animal is called
a(n) - Answers - pseudocoelomate
Some animals, such as flatworms, lack an internal body cavity. This type of animal is
called a(n) - Answers - acoelomate
Which phrases describe characteristics of both a true coelom and a pseudocoelom? -
Answers - In a coelomate, the tissue lining the inner side of the body cavity arises from
the same germ layer as the tissue lining the outer side of the body cavity
A diploblast has no mesoderm
A pseudocoelom has the same functions as a true coelom
Among the characteristics unique to animals is - Answers - gastrulation
The distinction between sponges and other animal phyla is based mainly on the
absence versus the presence of - Answers - true tissues
Acoelomates are characterized by - Answers - a solid body without a cavity surrounding
internal organs
Which of the following was probably the least important factor in bringing about the
Cambrian explosion? - Answers - the movement of animals onto land
Which of these is a point of conflict between the phylogenetic analyses presented in
Figures 32.10 and 32.11 in your textbook? - Answers - the relationship taxa of
segmented animals to taxa of nonsegmented animals
What is the key difference between a coelom and a pseudocoelom? - Answers - Only a
coelom is fully lined with mesoderm tissue
Identify the features that distinguish animals from organisms in other multicellular
kingdoms - Answers - animals are ingestive heterotrophs
, Select the correct statement about the evolution of animals - Answers - the oldest
generally accepted fossils of large animals range in age from 565 to 550 million years
old
Which feature of deuterostome development explains the formation of identical human
twins? - Answers - Deuterostomes have indeterminate development
Select the correct statement(s) about animal body plans - Answers - Development in all
animals is determined by the unique family of Hox genes (or other similar homeobox
genes)
Which of the following occurred during the Mesozoic era? - Answers - Flight evolved in
pterosaurs and birds
Which trait below is a common feature of all animals? - Answers - a homeobox-
containing family of genes called Hox genes
An animal with a true coelom that has ____ cleavage must be a ____. - Answers -
radial...deuterostome
Which of the following is associated with bilateral symmetry? - Answers - cephalization
Many young animals are _____, a sexually immature form that is morphologically
distinct from the adult stage. These young animals undergo _____ to become ____,
which resemble adults but are not yet sexually mature. - Answers -
larvae...metamorphosis...juveniles
Which characteristic below is shared by plants, fungi, and animals? - Answers - They
are multicellular eukaryotes
Indeterminate cleavage is a process that produces embryonic cells that ____. - Answers
- retain the capacity to develop into a complete embryo
Which example below is a current hypothesis regarding the Cambrian explosion? -
Answers - Evolution of the Hox gene complex provided developmental flexibility
In the embryo of a shark, ectoderm gives rise to ____; mesoderm gives rise to _____;
endoderm gives rise to _____. - Answers - the central nervous system...muscle...the
lining of the digestive tube
One of the primary developmental/anatomical characteristics distinguishing the major
animal phyla is the condition of the body cavity. A pseudocoelomate animal is one in
which the body cavity is _____. - Answers - formed from mesoderm and endoderm
Which of the following is characteristic of protostomes? - Answers - Cell fate is
determined early during embryonic development
A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A
postdoctoral student thinks it looks more like an aquatic fungus. How can they decide
whether it is an animal or a fungus? - Answers - Look for cell walls under a microscope.
All animals can trace their lineage to a common ancestor that lived in the _____. -
Answers - Neoproterozoic era
The earliest ancestors of about half of all extant animal phyla can be traced back to the
_____ explosion. - Answers - Cambrian
Which of the following is radially symmetrical? - Answers - A doughnut
Gastrulation is the process that directly forms the _____. - Answers - Primary germ
layers
Which of the following is NOT a characteristic of all animals? - Answers - They have
tissues, organs, and organ systems.
An important trend in animal evolution was cephalization. An animal is said to show
cephalization when it _____. - Answers - has an aggregation of sensory neurons at the
anterior end.
Which of the following animals does NOT have a body cavity? - Answers - Flatworm
During embryological development, the anus forms before the mouth in _____. -
Answers - humans
Which of the following statements is correct? - Answers - All animals share a common
ancestor
An animal that can be divided along at least different planes to produce mirror images is
said to have _____. - Answers - radial symmetry
An animal that cannot be divided along any plane to produce mirror images is said to
display _____. - Answers - asymmetry
An animal that can be divided along a single plan to produce mirror images is said to
have _____. - Answers - bilateral symmetry
_____ gives rise to the lining of the digestive tract or gut - Answers - endoderm
,_____ gives rise to muscles and most other organs between the digestive tract (or gut)
and the outer covering of the animal - Answers - mesoderm
_____ gives rise to the outer covering of the animal - Answers - ectoderm
An animal with only two embryonic germ layers, such as a jelly, is called a(n) _____ -
Answers - diploblast
An animal with three embryonic germ layers, such as a reptile or insect, is called a(n)
_____ - Answers - triploblast
Some animals, such as roundworms, have an internal body cavity that is formed from
both mesoderm-derived and endoderm-derived tissues. This type of animal is called
a(n) - Answers - pseudocoelomate
Some animals, such as flatworms, lack an internal body cavity. This type of animal is
called a(n) - Answers - acoelomate
Which phrases describe characteristics of both a true coelom and a pseudocoelom? -
Answers - In a coelomate, the tissue lining the inner side of the body cavity arises from
the same germ layer as the tissue lining the outer side of the body cavity
A diploblast has no mesoderm
A pseudocoelom has the same functions as a true coelom
Among the characteristics unique to animals is - Answers - gastrulation
The distinction between sponges and other animal phyla is based mainly on the
absence versus the presence of - Answers - true tissues
Acoelomates are characterized by - Answers - a solid body without a cavity surrounding
internal organs
Which of the following was probably the least important factor in bringing about the
Cambrian explosion? - Answers - the movement of animals onto land
Which of these is a point of conflict between the phylogenetic analyses presented in
Figures 32.10 and 32.11 in your textbook? - Answers - the relationship taxa of
segmented animals to taxa of nonsegmented animals
What is the key difference between a coelom and a pseudocoelom? - Answers - Only a
coelom is fully lined with mesoderm tissue
Identify the features that distinguish animals from organisms in other multicellular
kingdoms - Answers - animals are ingestive heterotrophs
, Select the correct statement about the evolution of animals - Answers - the oldest
generally accepted fossils of large animals range in age from 565 to 550 million years
old
Which feature of deuterostome development explains the formation of identical human
twins? - Answers - Deuterostomes have indeterminate development
Select the correct statement(s) about animal body plans - Answers - Development in all
animals is determined by the unique family of Hox genes (or other similar homeobox
genes)
Which of the following occurred during the Mesozoic era? - Answers - Flight evolved in
pterosaurs and birds
Which trait below is a common feature of all animals? - Answers - a homeobox-
containing family of genes called Hox genes
An animal with a true coelom that has ____ cleavage must be a ____. - Answers -
radial...deuterostome
Which of the following is associated with bilateral symmetry? - Answers - cephalization
Many young animals are _____, a sexually immature form that is morphologically
distinct from the adult stage. These young animals undergo _____ to become ____,
which resemble adults but are not yet sexually mature. - Answers -
larvae...metamorphosis...juveniles
Which characteristic below is shared by plants, fungi, and animals? - Answers - They
are multicellular eukaryotes
Indeterminate cleavage is a process that produces embryonic cells that ____. - Answers
- retain the capacity to develop into a complete embryo
Which example below is a current hypothesis regarding the Cambrian explosion? -
Answers - Evolution of the Hox gene complex provided developmental flexibility
In the embryo of a shark, ectoderm gives rise to ____; mesoderm gives rise to _____;
endoderm gives rise to _____. - Answers - the central nervous system...muscle...the
lining of the digestive tube
One of the primary developmental/anatomical characteristics distinguishing the major
animal phyla is the condition of the body cavity. A pseudocoelomate animal is one in
which the body cavity is _____. - Answers - formed from mesoderm and endoderm
Which of the following is characteristic of protostomes? - Answers - Cell fate is
determined early during embryonic development
