chapter 32 animal diversity and evolution of body plans

Select the key innovations in animal evolution.

Body cavity Segmentation Symmetry Tissues Various patterns of embryonic development

What are the flagellated cells that line the internal cavity of a sponge and help water flow through the Ostia called?

Choanocytes

Members of what phylum are characterized by a diploblastic, radially symmetrical body plan and, while not having organs and organ systems, possess distinct tissues?

Cnidaria

What organisms are included in the phylum Ctenophora?

Comb jellies

Comb jellies make up the phylum

Ctenophora

Which of the following phyla belong to the Deuterostomes?

Echinoderms Chordates

What clade includes all animals that have true tissues and body symmetry?

Eumetazoa

True or false: As molecular data has become widely available most of what was previously known about the deep relationships of animal phyla to each other has been proven wrong.

False

Which of the following correctly describes how a heterotrophic organism obtains energy and organic molecules?

Ingesting other organisms

Which of the following accurately describes the pseudocoelom?

It is a body cavity that develops embryologically between the mesoderm and endoderm.

Animals that undergo embryonic development where the embryonic blastopore develops to become the animal's mouth are

Protosomes

Which of the following refers to a type of body plan where an animal's body is divided into nearly identical units.

Segmented body plan

Choose the statement that most accurately describes the presence of tissues in animals.

Specialized tissues are found in all animals except sponges.

The only animals that lack any form of body symmetry are

Sponges

Which of the following statement best describes sponges?

Sponges have several types of cells that perform different functions

Which of the following accurately describes animals with a segmented body plan?

The animal's body is divided into nearly identical units.

Which of the following are characteristics of cnidarians?

They are made of distinct tissues. They are diploblastic. They have radial symmetry.

Which of the following statements about sponges is true?

They are multicellular but do not have true tissues.

Which of the following best explains why animals are considered monophyletic?

They have a common ancestor

Choose all characteristics of acoel flatworms.

They have bilateral symmetry. Their mouth leads to a solid digestive syncytium. They do not have a coelom.

Noncoelomate invertebrates, such as sponges and jellyfish, and noncoelomate worms, are evolutionarily important because of which of the following statements?

They possessed the basic animal body plan from which the body plan of all other animals evolved.

Which of the following is most true regarding molecular and traditional analysis of Metazoa?

Though there are differences between the two phylogenies, there is much agreement in the deep parts of the evolutionary tree.

How many clades does the Bilateria comprise?

Two

Animals that lack a coelom do not form a monophyletic clade; therefore,

animal classification cannot be based on whether or not an animal has a coelom

Sponges can reproduce simply by breaking into fragments, each of which continues to grow as a new individual.

asexually

Most sponges are

asymmetrical

The five key innovations in animal evolution include tissues, a body , various patterns of embryonic development, segmentation, and .

cavity, Symmetry

The flagellated cells that line the internal cavity of a sponge and help water flow through the ostia are known as

choanocytes

The largest class of is Anthozoa.

cnidaria

As their name implies, flatworms in the phylum Acoela lack

coelom

Based on ample evidence, the echinoderms and chordates form a monophyletic clade called the

deuterostomia

In contrast to Parazoa, the includes all animals that have true tissues and body symmetry.

eumetazoa

All animals descend from a common ancestor and are therefore

monophyletic

Protostomes are animals in which the embryonic blastopore becomes the

mouth

Despite their simplicity, the appearance of noncoelomate invertebrates was very important - these organisms possessed the basic animal body , from which that of all other animals evolved.

plan

A body cavity called the develops in an animal embryo between the mesoderm and endoderm.

pseudocoelom

In all animals except , cells differentiate into specialized which are groups of cells that take on particular functions in the animal's body.

sponges, tissues

All animals exhibit some form of body symmetry except

sponges.

Most sponges do not have a definite and do not possess tissues.

symmetry

Which of the following describes asexual reproduction in sponges?

A sponge can break into fragments and each fragment can become an individual.

Within phylum Cnidaria, the class that includes the most species is

Anthozoa

Why can't we base animal classification on whether or not an animal has a coelom?

Because the acoelomate and pseudocoelomate conditions have evolved multiple times

This group of animals is characterized by a transition to bilateral symmetry.

Bilateria

Protosteoms can be divided into two clades; and

Lophotrochozoa, Ecdysozoa

Select the terms that accurately describe an organism that obtains energy and organic molecules by ingesting other organisms

Omnivore Heterotroph Carnivore Detritivore