Biology Chapter 33

Systematics use several fundamental criteria to assign animals to phyla. Check all of the criteria that systematics would use to classify animals under specific phyla.

-Adult body symmetry -The embryological formation of body cavities -Gene sequences -The number of tissue layers

How could a biologist distinguish an ace flatworm from a free living platyhelminth?

The ace worm would be solid throughout, since it lacks a gut

A worm that is solid from the gut epithelium to the outermost epithelium would be considered

acoelomate

Damage to its flagellum would prevent a choanocyte from

circulating water through the sponge

Label the major germ layers and body cavities for the two body plans shown. Note: Three of the labels identify similar areas of each body plan. The other two labels are specific to each body plan.

-Left: pseudocoelom -Right: coelom -Middle from top to bottom: Ectodermally derived tissue, Endodermally derived tissue, Mesodermallly derived tissue

All species of animal have general features in common. Check all of the features that would apply to animals

-Most animals have the capacity for active movement -Animal zygotes undergo mitotic divisions called cleavage -All animals are heterotrophs

Select the true statements concerning ctenophores

-They have some tissue derived from mesoderm -They have a modified radial symmetry

Of the following features, which is the most widely shared in the animal kingdom?

A body plan with symmetry

Which feature would only be found in the Bilateria?

Anterior cephalization

Touching a jellyfish can be a very painful experience whereas touching a comb jelly is not painful. Why is there a difference?

Ctenophores do not possess nematocysts

Match the organisms with the type of development they exhibit

Deuterostome -sea star -human Protostome (Spiralia) -Earthworm -Snail -Bryozoan Protostome (Ecdysozoa) -Crustacean -Onychophora

Match the descriptions to the type of development with which they are associated

Protosome: -Spiral cleavage -Blastospore becomes mouth -Coelom forms from mesodermal cells that move apart from one another to create an expanding cavity within the mass of the cells -Determinate development Deuterostome -Coelom forms from cells that pouch off the end of the archenteron -Indeterminate development -Radial cleavage -Blastospore becomes anus

Arrange these animals in term of their relatedness to humans. The most closely related organisms first and the most distantly related organism last.

Sea star, crab, ace flatworm, jellyfish, sponge

Round worms (Phylum: Nematoda) move by essentially thrashing from side to side. Segmented worms (Phylum: Annelida) are capable of much more controlled and intricate movements. What feature of annelids, missing in nematodes, allows for the annelids' more complex locomotion?

Segmentation

Sponges are comprised of several cell types, which are similar to those found in the Eumetazoa, but also display a unique degree of flexibility. Complete the following sentences discussing sponge cell types.

Sponge cells are unique because throughout their development they can ___ from one type of cell to another -differentiate Sponges are truly ___ organisms -multicellular ______ are flagellated cells that line internal cavities and are responsible for pumping water and small particles into the sponge -Choanocytes The exterior of a sponge is comprised of flattened cells that form an outer ____ -epithelium The inner layer of a sponge, the meshy, contains several types of ___ cells, which secrete materials to form a skeleton-like structure for support -amoeboid

The two principle clades of protostomes are the Ecdysozoa and the spiral. Complete the following sentences describing the major characteristics of each clade

The___ animals are protostome that grow by gradual additions of mass to the body -Spiralian There are two main groups in this clade: the ___ and the Platyzoa -Lophotrochozoa The ____ animals are protostomes that grow step-wise by a process called molting. -ecdysozoan Of the many phyla falling under this clade, the ____ contains the largest number of described species of any phylum in the animal kingdom. -Arthropoda Members of this phylum are ___ animals with jointed appendages and segmented external skeletons composed of chitin. -coelomate

The segmentation of animals has allowed for several advantages. Indicate if the following statements concerning segmentation are true or false

a- locomotion is more efficient in segmented animals because independent segments can move semi-independently (True) b-partitions isolate each segment, so each must contract or expand in unison (False) c- In segmented animals like earthworms 9phylum Annelida), each segment may develop a nearly complete set of adult organ systems (true) d- Redundancy in segmented animals is not an advantage (false)

In a _____ circulatory system, circulating of blood is more controlled- the blood is moved faster and more efficiently than in other types of circulatory systems

closed

Choanocytes

filter particles out of the water

In the current animal classification system ____ is thought to have originated once, and ____ is thought to have evolved multiple times.

molting, segmentation

Animals with a body cavity located between the mesoderm and endoderm are

pseudocoelomate

The two largest clades in the Bilateral are the protostome and the deuterostomes

true