Exam 3: Chapter 30

Sponges have specialized cells, but those cells are not organized into:

tissues

Which group of organisms display radial cleavage during development?

echinoderms

A true body cavity completely surrounded by ____ is called a coelom.

Mesoderm

The ____ gives rise to muscles, bones, and the circulatory system.

Mesoderm

The common ancestor of all animals is/are the:

choanoflagellates.

Diploblastic animals, such as cnidarians and ____, have only two germ layers, ectoderm and ____.

ctenophores; endoderm

Indeterminate cleavage takes place in ____ and is characterized by a pattern of development where the ultimate fate of each cell is ____.

deuterostomes; not fixed until late in the developmental process

The epidermis of a nematode is derived from the:

ectoderm

True or False: Echinoderms do NOT show evidence of segmentation

TRUE

What is the key characteristic that defines the Ecdysozoa clade?

The animal molts.

What is a characteristic of ribbon worms and flatworms?

They are acoelomates.

One true characteristic of all animals is that they:

are heterotrophs.

The lining of the digestive tube is formed from:

endoderm

The first land animals likely moved onto land how long ago?

450 MYA

How is a pseudocoelom different from a coelom?

A coelom is a cavity fully lined by mesoderm.

The head end of an animal is known as its:

Anterior end

The diverse body plans seen in Animalia apparently developed during the:

Cambrian period

A body cavity

Coelom

True or False: Animals cannot respond to stimuli.

FALSE

If adult sponges are sessile, why can they still be classified as animals?

Sponge larvae are motile.

Cells of the blastula undergo ____, a process that forms and segregates the three germ layers.

gastrulation

A marine invertebrate placed into freshwater would have difficulty surviving because:

it would have difficulty with osmoregulation.

As a scientist, what would you use as evidence to propose changing the traditional animal phylogenies?

molecular data

A grasshopper belongs in the Ecdysozoa clade because of its ability to:

molt

In most protostomes, the blastopore develops into the:

mouth

Determinate cleavage takes place in ____ and is characterized by a pattern of development where the ultimate fate of each cell is ____.

protostomes; fixed early in the developmental process

What is a major problem for sessile animals?

They are unable to escape unfavorable environmental conditions.

What explains why fewer animals live in freshwater than in the ocean?

Freshwater is generally hypotonic to tissue fluids.

To include your eyes and ears in the same section, you would need to cut your body in which plane?

Frontal

What molecular evidence have been found in cnidarians, which have radial symmetry, that is evidence to indicate cnidarians share a common ancestor with bilateral animals?

Hox genes