MARB 215 Exam 3 HW

What is required for multicellularity on organisms?

- intercellular communications

- adhesion between cells

- specialty of functions in cells (some for feeding, some for reproduction, etc.)

Choanocyte

the flagellated cell responsible for water movement and food capture

pinacocyte

the exterior cells of a sponge, covering the mesohyl; control the surface area of the animal

archaeocyte

a cell that has multiple functions and can turn into any cell that is needed

osculum

the excurrent portion of the sponge (where water exits)

ostia (plural; ostium = singular)

the incurrent pores on the exterior of a sponge

spicules

structures made of CaCO3 or silica that provide structure and protection to most sponges

What are reasons the sponges are considered the sister group of all animals?

- they are the only animal without germ layers

- they have highly specialized cells, but no tissues or organs

- their choanocyte cells are nearly identical in form and function to choanoflagellates

the sponge body types of asconoid, syconoid, and leuconoid differ in:

amount of surface area devoted to water filtration

what trait do harp sponges and ping-pong sponges have that most sponges do not?

they are carnivorous (feed on small crustaceans and other small organisms)

true or false: the sponges have a MUCH simpler genome than all the other animals

false, their genome is complex like other "higher" genomes, but they don't express as many of their genes

spongin is a protein derived from ______ that gives support and structure to the mesohyl in the ________.

collagen, demospongiae

what are ways that sponges reproduce asexually?

- fragmentation

- budding

- gemmules

regarding sexual reproduction, sponges are _________.

simultaneously monoecious, sequentially monoecious, or dioecious

sponges excel at regeneration. What are reasons why they can regenerate so well?

- all it takes is a single cell to create a whole new organism ("somatic embryogenesis")

- the archaeocytes can become any type of cell that is required

- they lack tissues, so they only need to create the specialized cells necessary for life

Many sponges undergo a very unique step in early development called ________.

inversion

What do Placozoans use to move?

- cilia on the ventral surface

- contractile fiber cells between their dorsal and ventral tissues

what is the purpose of the "shiny spheres" on the dorsal surface of a Placazoan?

defense

true or false: the Placazoans are the first animals to exhibit true tissues.

true

What phyla are diploblastic?

- Placazoa

- Ctenophora

- Cnidaria

What phylums exhibit radial or biradial symmetry?

- Ctenophora

- Cnidaria

Both the Porifera and the Placozoa are the only asymmetrical animals

In the Phylum Cnidaria, the _____ stage is generally sexual and the ________ stage is asexual.

medusa, polyp

true or false: all Cnidarians have both a polyp and medusa stage in their development.

false, all Anthozoans have only a polyp stage, as do some of the hydrozoans. Only a few groups of Cnidarians have no polyp stage and are only medusoid

Cnidarians have a ________ gut. The endoderm becomes the _________ in the adult organism.

blind, gastroderm

What are cnidocytes used for in the Cnidarians?

- capturing food

- defense

- building a tube in which the animal can live

true or false: all diploblasts are eucoelomate

false, a coelom can only be formed from mesoderm, which the diploblasts lack

Class Hydrozoa

mostly colonial and marine; some with no medusa stage

Class Anthozoa

all marine, no medusoid body form

Class Myxozoa

obligate parasites that are microscopic; have polar capsules homologous to cnidocysts

Class Staurozoa

stalked jellyfish

Class Scyphozoa

Known for strobilation to produce its dominant medusa form

Class Cubozoa

Most primitive animals to exhibit well formed eyes

What gives the Phylum Ctenophore its name?

the 8 comb rows of cilia

true or false: Ctenophores are the most primitive animals to have a complete gut, some with a "fleeting" anus that only appears when needed to expel waste.

true

true or false: Ctenophores are strictly marine animals that are mostly planktonic, but can be found at great depths as well in all oceans

true

Which of the following are likely reasons the Xenocoelomorphs are considered the Sister goup to the nephrozoans (true bilateral animals)?

- their nerve net is very similar to what the Radiata animals have

- they have either a blind gut (like Cnidarians) or no gut

- they either lack organs or have only a few simple organs

- they lack cephalization

The Lophotrochozoans develop a coelomic cavity (even if its filled with parenchyma) via:

schizocoely

the simplest animal exhibiting a true head is found in the Phylum:

Platyhelminthes

Many of the Lophotrochozoans lack major organs. How do many of them perform gas exhange, waste removal, and nutrient absorption?

diffusion across the epidermis due to a very high SA:V ratio

true or false: all animal phyla have more than one species contained within them

false, the Micrognathooa has only a single species in it

Which of the following phyla does not have a U-shaped, complete digestive tract?

Rotifera

What is a lophophore used for?

- respiration

- feeding

Some animals exhibit a statocyst. What is this used for?

balance, because it is difficult to feel gravitational pull in water, some animals must use a statocyst to determine "up" from "down" in the water

What lends the greatest support to the idea that the Class Monogenea and Class Cestoda are sister taxa within the Phylum Platyhelmithes?

The body segment they use to attach to hosts was either at the posterior in the ancestor or is at the posterior of the extant animal

Phylum Gastrotricha

uses a pestle organ to detect chemical cues

Phylum Rotifera

simplest animal we studied that is dioecious

Phylum Micrognathozoa

Feed using very complex jaws that have 3 distinct regions

Phylum Nemertea

Contains a proboscis it can quickly shoot out of its rhynocoel to capture prey

Phylum Mesozoa

Compromised of only about 20 cells, most of which are used for reproduction

Phylum Ectoprocta

AKA bryozoans, or moss animals

Phylum Entoprocta

Have U-shaped gut, complete digestive tract with both the anus and the mouth contained within the lophophore

Phylum Acanthocephala

Thorny proboscis helps animals attach vertebrate to intestines

What are reasons the Brachiopoda are no longer classified in the Mollusca with the bivalves?

- all brachipods are sessile

- the valves are oriented as dorsal and ventral, not left and right

What is the phyla that has blood containing hemoglobin?

Phoronida

What are differences between the Entoprocta and Ectoprocta?

- whether the anus sits within or outside the lophophore

- Ectoprocts can retract into their zooecium, but entoprocts cannot retract into their calyx

true or false: all gastropods possess a shell

false

true or false: octopuses have 8 tentacles

false

true or false: ontogenetic torsion and coiling are the same thing

false

true or false: the Phylum Mollusca is the largest animal phylum

false

true or false: the parapodia in the polychaetes are used only for locomotion

false

true or false: all Hirudinids are freshwater

false

the Solenogasters and Caudofoveata comprise the Clade _________ because they _________.

Aplacophora, lack a shell

Class Polyplacophora

exhibits pseudometamerism of gills and muscles

Class Monoplacophora

One cap-like shell, poorly developed head; deep-sea and rare

Class Bivalvia

lacking a head and a radula, major food source for humans

Class Gastropoda

contains the only terrestrial molluscs

Class Cephalopoda

greatest brain:body mass of inverts

Class Scaphopoda

lacks a gill; uses mantle for gas exchange

what is true about ontogenetic torsion?

- some animals use coiling as a mechanism to avoid biofouling

- it could cause biofouling of the gills

What class uses a captacula to burrow?

Class Scaphopoda

What do cephalopods use to change their colors/patterns for comouflage and other behaviors?

chromatochores

What molluscan classes are strictly marine?

- Caudofoveata

- Monoplacophora

- Cephalopoda

- Solenogastre

- Polyplacophora

- Scaphopoda

Polychaetes have multiple bundles of chaetae, or hairs, extending from parapodia on each segment. What are the parapodia used for?

- locomotion

- respiration

true or false: Polychaetes may be either free-living or live in burrow or tubes that they build

true, most polychaetes are free-moving in the Clade Errantia

The _______ exhibits a trophosome, which is used for ____________. These worms live __________.

Family Siboglinidae, nutrition via chemosynthetic bacteria, near hydrothermal vents

Members of the Class Clitella all exhibit a clitellum. What is true of the clitellum?

- It appears only during mating in the Hirudinids

- It is always present in the Oligochaetes

- It is used for reproduction

There are currently ___ animal phyla recognized.  Use only numerals in your answer.

32

What type of symmetry is best suited for cephalization and forward movement?

bilateral

Most animals with radial symmetry are ________ and have _______sides of their body.

sessile or weak swimmers

oral/aboral

Chordates show a form of metamerism in the skeleton, musculature, and central nervous system

true

The peritoneum is found in acoelomates, pseudocoelomates, and eucoelomates

false

Most animals are diploblasts

false

Most animals have a complete gut

true

As animal body plans became more complex and larger, they were able to increase their adaptive diversification

true

In what ways do animal body plans differ?  

all of the answers shown

organ-system

most of the metazoans

cell-tissue

cnidarians

tissue-organ

many lower animals

protoplasmic

unicellular eukaryotes

cellular

sponges

An animal that can interact with its environment in 360^o typically exhibits __________ symmetry

radial

Match the plane to the body portions it bisects:

frontal

dorsal & ventral

Match the plane to the body portions it bisects:

transverse

anterior & posterior

sagittal

left and right sides

In the blastula stage, the embryo has germ layer(s) and ___ body cavity(ies).  After gastrulation, the embryo has ____germ layer(s) and ___ body cavity(ies).  Diploblasts have the germ layers of _________while triploblasts have the germ layers of _____________

1, 1, 2, 2, endoderm and ectoderm, (endoderm, ectoderm, and mesoderm)

A coelom formed through schizocoely is functionally the same as a coelom formed through enterocoely once they are fully formed.

true

Which of the following are benefits of metamerism in animals?

increased body mobility

increased complexity of body structure

As animal bodies became larger, they had to overcome the SA:V issues through internal folding, flattening of bodies, and/or internal transport through more complex organ systems.

true

Which of the following are benefits of having a larger body?  Choose all that apply.

Less energy expended to maintain body temperature

Greater buffer from environmental fluctuations

Greater protection from predators

Which of the following are required for multicellularity in organisms?  Choose all that apply.

adhesion between cells

specialty of functions in cells (some for feeding, some for reproduction, etc.)

intercellular communications