Protostomes

Question 1

What are the 2 sub-clades of Bilateria?

Answer 1

1. Protostomes (first mouth)
2. Deuterostomes (second mouth)

Question 2

What is the blastopore?

Answer 2

The blastopore is a pore/hole produced when cells fold inward and form the
archenteron during gastrulation

Question 3

A second pore is formed as the

Answer 3

archenteron travels inward and upward and reaches the end

Question 4

In protostomes, the blastopore becomes

Answer 4

the mouth and the second pore becomes the anus

Question 5

In deuterostomes, the blastopore becomes

Answer 5

the anus and the second pore becomes the mouth

Question 6

When did present day protostome and deuterostome phyla arise?

Answer 6

During the Cambrian Explosion

Question 7

The 2 subclades of the Clade Protostomia:

Answer 7

Lophotrochozoa and Ecdysozoa

Question 8

All Protostomes form 2 sister clades found from

Answer 8

molecular phylogenetics using the SSU rRNA gene

Question 9

Which clade contains a diverse group of animals, some of which have lophophores or trochophore?

Answer 9

Lophotrochozoa

Question 10

Lopophores

Answer 10

tentacle mouths

Question 11

Trochophore larvae

Answer 11

A distinct larval stage with band of cilia

Question 12

Lophotrochozoa contain:

Answer 12

1. lophophores (tentacle mouths)
2. trochophore larvae (a distinct larval stage with band of cilia)

Question 13

Which sister clade contains animals that undergo ecdysis/molting?

Answer 13

Ecdysozoa

Question 14

Ecdysozoa

Answer 14

Animals that undergo ecdysis/molting

Question 15

*All lophotrochozoans share a MRCA but their
evolutionary relationships

Answer 15

remain unclear (which
is why all of the phyla branch out together)

Question 16

Lophotrochozoa are named after:

Answer 16

A. Lophophores
(bryozoans and brachiopods)

B. Trochophore larvae: (mollusks and annelids)

Flatworms and rotifers have neither

Question 17

What are platyhelminthes?

Answer 17

Flatworms

Question 18

Platyhelminthes are soft bodied animals with:

Answer 18

few organs and incomplete digestive tract

Question 19

Incomplete digestive tract is

Answer 19

an evolutionary reversal

Question 20

2 sub clades of platyhelminthes

Answer 20

1. free-living predators
2. mostly parasites

Question 21

Planarian is a _____ and reproduces by ______ and is used to study _______

Answer 21

1) free-living predator
2) asexual fragmentation
3) regeneration

Question 22

Notable parasites of platyhelminthes are:

Answer 22

Blood flukes: causes schistosomiasis which kills 200,000/year

Tapeworms: reside in the large intestine but larvae can infect the brain and cause neurocysticercosis.

Question 23

Rotifer literally means “wheel bearer” – refers to

Answer 23

their ciliated mouths that look like rotating wheels

Question 24

Rotifers are very complex microscopic organisms with: (4)

Answer 24

1. eyespots
2. a brain
3. protonephridia (kidneys-like organs)
4. complete digestive tract with mouth & anus

Question 25

Some rotifers exist in populations that are almost entirely female and can reproduce

Answer 25

through parthenogenesis (virgin birth)

Question 26

What is parthenogenesis (virgin birth)?

Answer 26

a form of asexual reproduction in which females lay fertile eggs that become embryos without the need for male sperm

Question 27

(Lophophore phyla) Bryozoans =

Answer 27

moss animals

Question 28

(Lophophore phyla) Brachiopods =

Answer 28

arm-foot

Question 29

Byrozoans and Brachiopods are phyla of sessile organisms that use _______ to ______ bacteria and protists

Answer 29

lophophores to capture bacteria and planktonic protists

Question 30

Bryozoans form large colonies that look like coral but are not cnidarians! Brachiopods look like clams but are not even mollusks! This is an example of:

Answer 30

convergent evolution

Question 31

Trochophore phyla: What are the most complex lophotrochozoans?

Answer 31

Annelids and mollusks

Question 32

The larval stage of annelids and mollusks is characterized by

Answer 32

trochophore larvae

Question 33

Annelids

Answer 33

("little rings") are segmented worms

Question 34

*Annelids have: (5)

Answer 34

1. circulatory system 2. kidney like organs 3. cluster of nerve cells 4. ventral nerve chord 5. complete digestive system with mouth & anus

Question 35

Annelids can be ____, _____, or _______

Answer 35

sedentary (earthworms and leeches), sessile, warning predators

Question 36

Mollusks are a diverse phylum with

Answer 36

3 sub-clades

Question 37

What are the 3 sub-clades of mollusks?

Answer 37

1. Bivalves (2 valves): clams 2. Gastropods (stomach foot): snails, slugs 3. Cephalopods (head foot): octopi, squid

Question 38

What is the synapomorphy of mollusks?

Answer 38

an organ called a mantle

Question 39

What does a mantle produce?

Answer 39

produces a calcium carbonate shell in most mollusks

Question 40

All extant cephalopods lack: This is an example of

Answer 40

a shell evolutionary reversal

Question 41

What is the synapormphy of clade ecdysozoa?

Answer 41

molting of cuticle

Question 42

The MRCA of ecdysozoans evolved

Answer 42

cuticle

Question 43

What is the cuticle of ecdysozoans?

Answer 43

A tough outer layer that protects them from dehydration on land - critical to colonization of land

Question 44

What are the first animals to colonize land?

Answer 44

Ecdysozoan

Question 45

What must ecdysozoans do to grow?

Answer 45

Ecdysis: must shed their old, inflexible cuticle (ecdysis) to expose the new, soft cuticle underneath which expands and then hardens

Question 46

2 clades of ecdysozoans

Answer 46

nematodes and arthropods

Question 47

C. elegans is an important model for ______ because

Answer 47

developmental bio; every cell division during development can be tracked

Question 48

What are nematodes?

Answer 48

Nematodes are tiny, ubiquitous, unsegmented worms with a cuticle made of collagen.

Question 49

Are nematodes free-living or parasitic?

Answer 49

Most are free-living predators but many are parasitic

Question 50

How can parasitic nematodes affect humans?

Answer 50

Some parasitic roundworms block lymphatic ducts and cause elephantiasis (Affects ~120 million per year in tropical countries)

Question 51

What make up most of animal diversity?

Answer 51

Arthropods

Question 52

Arthopod Synapomorphies

Answer 52

1. segmentation 2. jointed appendages 3. exoskeleton 4. tracheal system

Question 53

Segmentation

Answer 53

allows for complex body patterns

Question 54

Jointed appendages

Answer 54

Jointed appendages that allow for improved movement on land * “Arthropod” means “jointed foot” * Critical for colonization of land!

Question 55

Exoskeleton

Answer 55

extra tough cuticle made of chitin + proteins * Prevents dehydration and provides protection * Chitin in arthropods and fungi is a product of convergent evolution!

Question 56

Tracheal system

Answer 56

Tracheal system allows arthropods to breathe through their exoskeleton (via spiracles) and deliver oxygen to cells

Question 57

Segmentation is a product of

Answer 57

convergent evolution