Module 4 Q. 1-204

Which of the following represents the symmetry of a sea anemone?

Radial symmetry

Which of the following is considered a likely explanation for the events of the Cambrian explosion?

Complex predator-prey relationships and increased atmospheric oxygen levels promoted animal diversification

What characterizes the Cambrian period?

Diversification of animals

Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their
nutrition by ________.

ingesting materials

Both animals and fungi are heterotrophic. Which of the following distinguishes animal heterotrophy from fungal heterotrophy?

most animals derive their nutrition by ingesting materials

Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion?

the origin of Hox genes and the addition of new microRNAs

Which types of data are used to estimate phylogenies in modern zoology?

Molecular data

Which of the following statements concerning animal taxonomy is accurate?

Animals are thought to have evolved from flagellated protists similar to modern choanoflagellates

Hox genes in animals regulate the formation of the anterior-posterior axis and other aspects of development.

True

The common ancestors of living animals were similar to present-day choanoflagellates

True

What kind of body cavity does a coelomate animal have?

Coelom

The previous figure shows a chart of the animal kingdom set up as a modified phylogenetic tree. Use the diagram to answer the following
questions. Which group contains diploblastic organisms?

I

What are some shared derived characteristics that define the clade Bilateria? (Select all that apply)

Bilateral symmetry, Presence of three germ layers

Which of the following is (are) unique to animals?

nervous conduction and muscular movement

Animals lack cell walls which are a structural feature of plants and fungi

True

What shared characteristic does the clade Ecdysozoa refer to?

They secrete external skeletons and shed them during their lifetime

Which of the following was probably the least important factor in bringing about the Cambrian explosion?

the movement of animals onto land

The traditional and molecular views of animal phylogeny agree on all majorpoints

False

Which of the following was an early selective advantage of a coelom in animals?

it contributed to a hydrostatic skeleton, allowing greater range of motion

Which are traits of animals with radial symmetry? (Select all that apply)

They meet the environment equally well from all sides, they often are sessile or planktonic

How does the blastula form in animal development?

Through mitotic cell divisions

An adult animal that possesses bilateral symmetry is most certainly also ____

triploblastic

What are the major points of agreement between phylogenetic hypotheses based on morphological data and those based on molecular data? (Select all that apply)

All animals share a common ancestor, animals are monophyletic, sponges are basal animals

Based on the tree shown, which statement is false?

Acoelomate flatworms are more closely related to echinoderms than to annelids

What are the defining characteristics of triploblastic animals? (Select all that apply)

They have three germ layers, they develop a coelom or pseudocoelom, they include a broad range of animals, from arthropods to vertebrates

The mesoderm is the germ layer that gives rise to the outer covering of the animal.

False

What is the probable sequence in which the following clades of animals originated, from earliest to most recent?
1. tetrapods
2. vertebrates
3. deuterostomes
4. amniotes
5. bilaterians

5 → 3 → 2 → 1 → 4

All animals…

are heterotrophic

Pseudocoelom is a fully functional body cavity

True

Which characteristics are unique to animals? (Select all that apply)

Presence of Hox genes, presence of nerve and muscle cells

Body symmetry in animals affects swimming in which of the following ways?

Bilaterally symmetric animals can be streamlined for swimming, but radially symmetric animals cannot

Animals directly evolved from…..

Protists

What is the distinction between a larva and an adult animal? (Select all that apply)

Larva is a sexually immature stage that is morphologically different from the adult stage

Sponges, the simplest living animals, contain Hox genes

False

One hypothesis suggests that the Cambrian explosion was caused by the rise of predator-prey relationships. This hypothesis is best supported by an increased incidence of which of the following fossil traces?

Protective shells

What are the characteristics of animals? (Select all that apply)

Multicellular, heterotrophic, lacks cell wall

Animals are autotrophic eukaryotes

False

The distinction between sponges and other animal phyla is based mainly on the absence versus the presence of…

True tissues

What are the functions of a body cavity in an animal? (Select all that apply

It cushions the suspended organs, it allows for the development of a hydrostatic skeleton, it enables the internal organs to grow and move independently of the outer body wall

The Cambrian explosion was characterized by a decline in animal diversification

False

During the Cambrian explosion approximately 535 to 525 million years ago…

Animals rapidly diversified in the oceans

Phylogenetic trees are best described as…

Hypothetical portrayals of evolutionary relationships.

In deuterostome development, the blastopore usually develops into the mouth

False

Sponges belong to the eumetazoan clade…

False

Acoelomates are characterized by….

A solid body without a cavity surrounding internal organs

What is a defining characteristic of deuterostome development?

The blastopore develops into the anus

What are some of the hypotheses for the cause of the Cambrian explosion? (Select all that apply)

New predator-prey relationships, increased oxygen in the atmosphere, development of Hox genes

What distinguishes a coelomate animal from a pseudocoelomate animal is that coelomates…

have a body cavity completely lined by mesodermal tissue, whereas pseudocoelomates do not

The distinction between sponges and other animal phyla is based mainly on the absence versus the presence of….

Tissues

Most animal phyla belong to the clade Bilateria

True

Which two groups have members that undergo ecdysis?

III and IV

: Which unique cell types are found only in animals?

Nerve cells and muscle cells

Sponges lack true tissues

True

What distinguishes eumetazoans from other animals?

They have true tissues

At one time, sponges were lumped into one phylum. Then, they were separated into several different phyla. Now, they are considered one phylum again. These changes indicate which of the following?

Every phylogeny should be considered a hypothesis that must be revised in the light of new data

Which of the following environmental changes is thought to have contributed to the Cambrian explosion?

An increase in oxygen levels in the atmosphere

Which of the following differentiates animals from plants and fungi?

Presence of Hox genes

Typical animal embryos have ________, or external cell layer, and ________, which lines the digestive tract

an ectoderm; an endoderm

What are the major clades of bilaterally symmetrical animals suggested by molecular phylogenies?

Deuterostomia, Lophotrochozoa, and Ecdysozoa

What is the primary function of Hox genes?

Control of animal morphology through the regulation of other genes

Which of the following structures in insects functions in gas exchange?

Spiracles

The ________ is a flagellated cell that sweeps water through a sponge's body

choanocyte

Tapeworms are similar to fungi in that..

They feed by absorption

The most numerous, diverse, and widespread animals are the…

Arthropoda

Which of the following items demonstrates radial symmetry?

an apple pie

According to the "new" revised phylogeny based on genetic analyses, annelids are a member of the Lophotrochozoa and are most closely related to which of the following groups?

molluscs

Which of the following statements is true?

Arthropods have an open circulatory system, while annelids have a closed circulatory system

All cnidarians are motile

False

What are the functions of the gastrovascular cavity in cnidarians? (Select all that apply)

Digestion, absorption of nutrients, expulsion of undigested remains

Which of the following are not included among the eumetazoans that have true tissues?

sponges (Porifera)

What are the main parts of a mollusc's body? (Select all that apply)

Muscular foot, Visceral mass, Mantle

A land snail, a clam, and an octopus all share..

a mantle

What reproductive strategies do Planarians use? (Select all that apply)

Asexual reproduction, sexual reproduction

Sponges are highly mobile animals

False

What are the major threats to coral reefs? (Select all that apply)

Pollution, Overfishing, Global warming

exible, longitudinal rod that is located between the digestive tract and the nerve cord in chordates is called the…

notochord

Which phylum is characterized by animals that have a segmented body?

Arthropoda

What differentiates sponges from most other animal groups?

They lack true tissues

Which of the following are true about sea cucumbers? (Select all that apply)

Lack spines, Reduced endoskeleton

Which of the following characteristics of parasites explains how parasitism has become so widespread among living organisms?

Parasites do not generally kill their hosts; thus they can feed on the same host throughout the host's normal life span and do not have competition from decomposers

How do hydras reproduce under favorable conditions?

Asexually, by budding

Most sponges are sequential hermaphrodites, meaning they can produce both sperm and eggs, though not simultaneously.

True

Which of the following is a typical characteristic of molluscs?

a rasping organ called the radula

Which characteristic is shared by cnidarians and flatworms?

a digestive system with a single opening

Tapeworms absorb food from their hosts across their body surface

True

Which of the following features is unique to chordates?

a notochord

What is the basic body plan of cnidarians?

A tube with a single opening acting as mouth and anus

Which of the following is a characteristic feature of arthropods?

segmented bodies and jointed appendages

Most adult insects have three major body parts or sections. They are the….

head, thorax, and abdomen.

Why do large animals need specialized organs for gas exchange?

surface area increases more rapidly than volume as size increases

What is the significance of amoebocytes in the body of a sponge?

They wander through the mesohyl, digesting food and carrying nutrients to other cells

Which of the following statements applies to both nematodes and arthropods?

grow in conjunction with shedding of their exoskeleton

The fluid in the pseudocoelom of rotifers serves as a hydrostatic skeleton

True

Which of the following groups of organisms has flagella associated with its method of feeding?

sponges

Use the information to answer the following question.
The nontaxonomic term sea slug encompasses a wide variety of marine gastropods. One feature they share as adults is the lack of a shell. One
might think, therefore, that they represent defenseless morsels for predators. In fact, sea slugs have multiple defenses. Some sea slugs prey on
sponges and concentrate sponge toxins in their tissues. Others feed on cnidarians, digesting everything except the nematocysts, which they then
transfer to their own skins. Whereas the most brightly colored sea slugs are often highly toxic, others are nontoxic and mimic the coloration of the
toxic species. Their colors are mostly derived from pigments in their prey. There are also sea slugs that use their coloration to blend into their
environments.
This nudibranch, a type of sea slug, has many reddish cerata on its dorsal surface, as well as two white-tipped rhinophores located on the head.

Which structure do sea slugs use to feed on their prey?

a radula

Which of the following groups is characterized by having a tough, external cuticle that must be molted as the animal grows?

arthropods

Nematocysts can inject poison into the prey.

True

The crown-of-thorns sea star, Acanthaster planci, preys on the flesh of live coral. If coral animals are attacked by these sea
stars, then what part of the coral actually provides nutrition to the sea star?

polyps

What is the function of choanocytes in sponges? (Select all that apply)

Capturing and digesting food particles, Facilitating reproduction

What is unique to the cnidarian nervous system? (Select all that apply)

Association with sensory receptors, Noncentralized nerve net