Lecture Exam 3

What evolutionary trend explains the diversity of animal body plans?

A series of evolutionary innovations

What type of data is helping clarify the animal phylogenetic tree?

Molecular data

What major evolutionary development distinguishes more complex animals from simple ones?

The evolution of true tissues

What is the defining characteristics of annelids?

Body divided into repeated segments

What type of circulatory system do annelids have?

Closed circulatory system

What structure allows annelids to move using a hydrostatic skeleton?

Coelomic fluid

What are chaetae?

Bristles made of chitin used for locomotion

Are nematodes segmented or unsegmented?

Unsegmented

What covers the body of nematodes?

A flexible, thick cuticle that is molted

What is the function of the pharynx in nematodes?

Creates a sucking action

What disease is caused by eating undercooked pork infected with nematodes?

Trichinosis

What percentage of all names species are arthropods?

Segmentation, exoskeleton, jointed appendages

What is the arthropod exoskeleton made of?

Chitin and protein

What is ecdysis?

Molting of the exoskeleton

What type of mouthparts do Chelicerata have?

Chelicerae (fangs or pincers)

How many legs to spiders have?

8 legs (4 pairs)

What distinguishes crustaceans from other arthropods?

Two pairs of antennae and biramous appendages

What body regions do insects have?

Head, thorax, abdomen

What is the main reason for insect diversity?

Evolution of flight

What is metamorphosis?

Change in body form from immature to adult stage

What is the difference between complete and incomplete metamorphosis?

• Complete: drastic change (e.g., caterpillar → butterfly)

• Incomplete: nymph resembles miniature adult

What does the blastopore become in deuterostomes?

Anus

What are the two main groups of deuterostomes?

Echinoderms and chordates

What type of symmetry do adult echinoderms have?

Pentaradial symmetry

What system is used for movement in echinoderms?

Water vascular system

What structure is used for locomotion in echinoderms?

Tube feet

What are the 4 defining features of chordates?

1. Pharyngeal slits

2. Notochord

3. Dorsal nerve cord

4. Post-anal tail

What distinguishes vertebrates from other chordates?

Vertebral column

What type of circulation do fish have?

Single-loop circulation

What structure helps bony fish control buoyancy?

Swim bladder

What is the skeleton made of in sharks?

Cartilage

Why must amphibians reproduce in water?

Their eggs lack watertight membranes

What type of respiration do amphibians use in addition to lungs?

Cutaneous respiration (through skin)

What are the 4 key features of amniotes?

1. Amniotic egg

2. Dry skin

3. Thoracic breathing

4. Ectothermy

What is the function of the amnion?

Surrounds embryo in fluid

What are the two main distinguishing features of birds?

Feathers and flight skeleton

How do bird lungs differ from mammals?

Unidirectional airflow

What are the defining traits of mammals?

Hair and mammary glands

What type of heart do mammals have?

4-chambered heart

What is the function of the placenta?

Nutrient exchange between mother and embryo

What is the difference between complete and incomplete digestive systems?

Complete: separate mouth and anus

Incomplete: one opening

Where does most digestion and absorption occur?

Small intestine

What organ produces bile?

Liver

What are the 4 steps of gas exchange?

1. Ventilation

2. Diffusion

3. Circulation

4. Diffusion of cells

What type of flow maximizes oxygen exchange in fish gills?

Countercurrent flow

The diversity of animal body plans is primarily the result of":

A series of evolutionary innovations

Which of the following is a defining characteristics of annelids?

Segmented body plan

What type of circulatory system do annelids possess?

Closed

Nematodes are best described as:

Unsegmented with a molting cuticle

Which structure allows nematodes to pierce host tissues

Sylets

Arthropods are successful largely due to all EXCEPT:

Internal bones

The arthropod exoskeleton is primarily composed of:

Chitin

What is ecdysis?

Molting of the exoskeleton

Which arthropod group has two pairs of antennae?

Crustaceans

Insects are especially successful due to:

Evolution of flight

Which organism belongs to Chelicerata?

Spider

A centipede differs from a millipede in that centipedes:

Have one pair of legs per segment

Which group is a deuterostome?

Echinoderms

In deuterostomes, the blastopore becomes the:

Anus

Which is a defining feature of echinoderms?

Water vascular system

Which is NOT a chordate characteristic?

Ventral nerve cord

What distinguishes vertebrates from other chordates?

Vertebral column

What structure helps fish maintain buoyancy?

Swim bladder

Sharks differ from bony fish because sharks have:

Cartilage skeleton

Amphibians must reproduce in water because:

Their eggs lack protective membranes

Which feature is unique to amniotes?

Amniotic egg

What is the function of the amnion?

Protect embryo in fluid

Birds are closely related to:

Reptiles

What is a key adaptation for bird flight?

Hollow bones

Which is a defining mammalian trait?

Mammary glands

A complete digestive system has:

Mouth and anus

Where does most nutrient absorption occur?

Small intestine

Which organ produces bile?

Liver

Which of the following is NOT one of the 4 steps of gas exchange?

Digestion

Countercurrent flow in fish gills:

Maximizes oxygen exchange

Animal diversity =

evolutionary innovations

Key advancement =

True tissues

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

The animal’s body divided into similar units, at least during early development

Sponges are usually asymmetrical and do not possess _________ despite having certain highly specialized cells

tissues

What exhibits radial symmetry?

Cnidaria & Ctenophora

The protostome clade Ecdysozoa contains animals that _____

molt

In contrast to the Parazoa, all Eumetazoans _____

Have tissues and some kind of symmetry

What are characteristics of rotifers?

• They can lengthen and shorten their body

They are about 50-500 micrometres long

Two taxa of animals that exhibit radial symmetry are the _____

Cnidarians and Ctenophorans

What is the mantle of a mollusk?

A heavy fold of tissue wrapped around the visceral mass

Which of the following does a mollusk use for movement?

Foot

Gastropods:

Are terrestrial mollusks in which the mantle secretes a hard shell

Bivalves:

These mollusks are filter feeders and have a two-part shell with a hinge

Cephalopods:

These mollusks have a modified mantle cavity which creates a jet propulsion system

What is the function of a bivalve’s nephridium?

Removal of wastes

The annelid body plan can be described as which of the following?

A tube within a tube

Which class do snails and slugs belong to?

Gastropods

Which class do clams and scallops belong to?

Bivalves

Which class do octopuses and squids belong to?

Cephalopods

What type of skeleton do annelids have?

A hydrostatic skeleton

What structure removes wastes from a mollusk’s body?

The nephridium

The mollusk’s mouth may contain a rasping, tonguelike organ that has many teeth and is used for feeding. This unique organ is called the _____

Radula

What is the name of the chitinous bristles found on each segment of most annelids

Chaetae

Annelids have a fluid-filled _____ coelom that acts as a _____ skeleton

Coelom

Hydrostatic

Annelid segments are separated internally from one another by _____

septa