Exam 2: Mastering Biology Questions

As a group, invertebrates are _____.

paraphyletic

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.

Which of the following characteristics does not apply to cnidarians?

have a central nervous system

What does it mean to have a cephalothorax? In what groups do we see this in? List ALL classes with this structure.

head & trunk regions: crustacea, chelicerata, myriapoda

Lophotrochozoan phyla include _____.

mollusks, annelids, and flatworms

The vertebrate spinal cord develops from the embryonic _____.

dorsal hollow nerve cord

In your body, the inside "tube" within a "tube" is derived from the _____.

endoderm

Nematodes and arthropods both _____.

grow by shedding their exoskeleton

Think of your favorite vertebrate, what characteristics make it a vertebrate?

> Closed circulatory system > Internal skeleton > Skull > Vertebrae column

Suppose I have never taken Bio 211 and know nothing about Hagfish. How might you explain Class Myxini to me using their characteristics?

> Produce slime > Have cartilage > No jaws > Hooked teeth to attach to hosts

What traits developed in the Cambrian era?

> Vertebrae > Complex skull > Rayed fins

Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate). >An acoelomate triploblast has no endoderm. >The digestive tract of a coelomate functions as a coelom. >A diploblast has no mesoderm. >A pseudocoelom has the same functions as a true coelom. >In a pseudocoelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the muscles. >In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the lining of the digestive tract. >In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity.

>A diploblast has no mesoderm. >A pseudocoelom has the same functions as a true coelom. >In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity.

List the characteristics for the following phyla: Nematoda Arthropoda

>Exkoskeleton, roundworms, bilateral >Largest phylum, 2 body sections, jointed appendages

Describe the characteristics for each of the following phyla Platyhelminthes Mollusca Annelida

>Flatworms: acoelomates, parasitic, bilateral symmetry >Clams: soft-bodied, shell made of calcium carbonate, radial symmetry, mantle > Segmented worms: bilateral symmetry, live in fresh, marine, or damp soils

Choose two of the three hypotheses that attempt to explain this era, and describe them

>Increase in O2 levels: allowed for more organisms to flourish >Hox gene: created more morphological diversity > Predator-prey relationship: predators had to become quicker, prey had to become better at hiding & camouflaging

What are the four characteristics of chordates? Briefly explain their importance.

>Post-anal tail >Dorsal hollow nerve chord > Pharyngeal slits > Notochord

Define characteristics for the following phyla • Calcerea • Cnidarian • Ctenophores

>Sponges: filter feeders, diploblastic, asymmetrical, sessile >Jellyfish: polyp & medusa form, radial symmetry, true tissues >Comb jellies: cilia, radial symmetry, true tissues

Cnidarians are the oldest organisms with true tissues. Which clade does this place them in?

Eumetazoa

Which structure is not an innovation that occurred during vertebrate diversification?

Exoskeleton

True or false? An organism that is radially symmetric has many well-developed head regions.

False

List and describe the 3 adaptations that insects have. Explain how they contribute to the insects' success.

Flight Specialized mouth parts Metamorphosis

List the mollusk body plan

Foot, visceral mass, mantle

What class do slugs belong to? Muscles and clams?

Gastropoda Bivalvia

_________ is a process that rearranges the developing embryo to form germ layers.

Gastrulation

We have jaws, therefore, we are considered ________________. What is the advantage to having jaws?

Gnathostomes

What gene is responsible for the morphological development of an organism?

Hox gene

What are chelicerae? Where do we see this?

Mouth pinchers, Class Chelicerata

What synapomorphy (shared, derived trait) distinguishes animals as a monophyletic group, distinct from choanoflagellates?

Multicellularity

In what era was there a large appearance of many diverse species?

Paleozoic Era (Cambrian Explosion)

Which structure can be used for feeding and gas exchange?

Pharyngeal gill slit

Corals are what body form?

Polyp

Cnidarians often alternate between two life stages ___________ and _______________

Polyp, Medusa

Cniadarians have two body forms: sessile and motile. Give the name for each and describe what it means.

Polyp: sessile (can't move on its own) Medusa: motile (can move on its own)

What is a cnidocyte?

Projectiles that shoot from the tentacles of jellyfish that cause stings

Which group (clade) contains both ecdysozoans and lophotrochozoans AND how is it defined?

Protostomes, mouth forms from the blastopore

Which character would allow you to identify something as an echinoderm and not a chordate?

Radial symmetry

What do choanocytes do?

Specialized cell structures that pump water thru the sponge for feeding

Which of the following statements about vertebrates is true?

The development of an amniotic egg and internal fertilization allowed vertebrates to reproduce away from water.

What is significant about cephalization?

A concentration of sensory organs allows better detection of threats for motile organisms.

Which of the following statements about deuterostomes is false?

All deuterostomes exhibit radial symmetry in their bodies.

What one characteristic do we know all animals in Ecdysozoa must have? Hint: look at the name!

All have exoskeletons (shed=ecdysis)

Where should the origin of spiral cleavage be placed on the phylogenetic tree?

At the base of Lophotrocozoa

What era did we see the dinosaurs disappear and mammals flourish?

Cenozoic Era

You study squid for a living, what are you a specialist of?

Cephalopods

What is the only group of Mollusca that does NOT have a radula?

Bivalves

The major branches of Eumetazoa are the Radiata and the Bilateria. These names refer to what characteristic of these animals?

Body symmetry

What does it mean to be hermaphroditic? Which phylum displays this most?

Both female & male reproductive organs; Phylum Calcerea

One trait that is shared by the Lophotrochozoa and Ecdysozoa is_____.

Both groups are bilaterally symmetric triploblasts with the protostome pattern of development.

Among arthropods, only ________ possess specialized mouthparts that were a major adaptation for their radiation and diversification.

Insecta

You find what you believe is a new species of animal. Which of the following characteristics would enable you to argue that it is more closely related to a flatworm than it is to a roundworm?

It has no coelom.

Why is metamorphosis a key adaptation in insects?

It reduces competition for food resources between parent and offspring

_________ are jawless, while we saw the development of jaws in__________________.

Lampreys Chondrichthyes

What are the 3 bilaterian clades?

Lophotrochozoans Deuterostomia Ecdysozoa

What do all deuterostomes have in common?

The pore (blastopore) formed during gastrulation becomes the anus.

Which characteristics define a chordate?

The presence of four specific morphological traits

Which characteristic distinguishes echinoderms from the other two deuterostome lineages?

Their body plan

Why aren't urochodata actual chordates?

They have 3/4 characteristics of chordates in the larval stage

What does trochophore and lophophore mean? Based on these two words, what can we infer about Lophotrochozoans?

Trochopohore: larval stage Lophophore: adult stage

What four classes fall under Phylum Platyhelminthes?

Tubellaria Trematoda Cestoda Monogenea

In parasites, what is an intermediate host?

Where larva develop

Lophotrochozoans have the following except

an anus that derrives from the blastopore

What protein holds the animal cell together?

collagen

In a parasitic life cycle, asexual reproduction occurs ____.

in the intermediate host

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

ingesting it.

Which of the following is a characteristic of all chordates at some point during their life cycle?

post-anal tail

In organisms that exhibit _______ cleavage, cell fate is determined ___________, whereas in organisms that exhibit ___________ cleavage, cell ,fate is determined ______________.

spiral, early; radial, later

Which evolutionary innovation was most significant in helping tetrapods move to dry terrestrial environments?

the amniotic egg

What happens in gastrulation? What does it form?

the blastula folds in on itself & creates the blastopore & 3 germ layers

The development of what structure determines whether an animal will be a protostome or deuterstome?

whether the blastopore becomes the mouth or the anus