Worms

Question 1

name 3 ways that muscles move a worm

Answer 1

• hydrostatic skeletons
• body cavities
• lattices

Question 2

name the different worm phyla

Answer 2

• rotifera
• nematomorpha
• nemertea
• nematoda
• annelida
• platyhelminthes

Question 3

explain the mollecular mechanism of worms, how extracellular compounds allow a worm to move in a unique way

Answer 3

there are charged molecular background. The like charges repel, creating a linear extension. Thus a blob will brow into a cylindar

Question 4

why does NS favour the charged molecular background of a worm?

Answer 4

• the soft tissue is resistant
• damage repair
• they can vary in size (1mm-30m)
• can have directional movement (dorsal-ventrally, bilaterally)

Question 5

worms are ____blastic. what dermal layers does this include?

Answer 5

triploblastic

• mesoderm
• ectoderm
• endoderm

Question 6

why are hydrostatic skeletons awesome?

Answer 6

• water is incompressible (shape vs volume)

- soft bodied animals can re-extend their muscles due to coelom.

Question 7

explain the movement of an earthworm

Answer 7

• longitudinal muscles contract alternately acting against the internal fluid.
• bristles grip
• peristalsis

Question 8

what is peristalsis?

Answer 8

the manner which radial muscles can contract and relax to move the animal across a plane.

Question 9

describe an acoelomate. name the phyla that have this.

Answer 9

• no body cavities
• muscles work against intracellular water only
• muscular waves for slow propulsion.
• platyhelminthes, nemertea

Question 10

pseudocloelomates. describe and name the phyla

Answer 10

• lack a mesoderm layer between the cavity and the gut.

- Nematoda, Rotifera

Question 11

coelomates. describe, phyla

Answer 11

• much more effective hydrostatic skeleton
• bounded on all sides by mesoderm
• annelida

Question 12

mesoderm= what? quick think reference. how does it affect movement?

Answer 12

mesoderm=muscles. movement is easier

Question 13

describe lattices

Answer 13

hydrostatic skeletons need support

• hydrostatic skeletons need support
• connective tissue lattices
• threads of collagen
• impressible in length
• wound helically
• can contract evenly, without bulging or kinking, lattice angle changes.

Question 14

disadvantages to a hydrostatic skeleton

Answer 14

• skeleton depends upon hydration
• -confined ecologically
• -water weight
• lots of muscle required to move body
• -everywhere, not just legs
• -friction
• -locomotion inefficient
• harder nerves to control
• -precision impossible
• predation

Question 15

advantages of a hydrostatic skeleton in regards to resistant to impact damage

Answer 15

• worms do not readily break, buckle or burst

- distortion are not harmful, and happen easily

Question 16

what is the latin meaning for Rotifera?

Answer 16

wheel bearer

Question 17

in what type of water do rotifers exist?

Answer 17

fresh water

Question 18

how do rotifers move?

Answer 18

propelled. crown, wheeled corona

Question 19

what is the exterior of a rotifer made of?

Answer 19

ciliated epidermis,
intracellular lorica.
resistant resting stage

Question 20

how do rotifers reproduce?

Answer 20

parthenogenesis

Question 21

what is another word for virgin birth?

Answer 21

parthenogenesis

Question 22

what does Nematomorpha mean in greek? common name?

Answer 22

thread shape. Hair worms

Question 23

where would one find a Nematomorpha? (2 places)

Answer 23

• fresh water damp soil

- young parasitic in arthropods

Question 24

what sort of muscle do nematomorphas have? how do they move?

Answer 24

only longitudinal muscle.

contracting in propagated waves for locomotion

Question 25

what type of lifestyle do nematomorphas have?

Answer 25

parasitic, definitive

Question 26

Nemertea aka:

Answer 26

Rhynchocoela

Question 27

what is the latin meaning of nemerteas?

Answer 27

thread, nose coelom

Question 28

what are the two types of nemerteas?

Answer 28

proboscis worms

ribbon worms

Question 29

what environment do nemerteas typically exist in?

Answer 29

predominantly marine

Question 30

how do nemertines resemble platyhelminthes?

Answer 30

-triploblastic
-enclose a gut
-acoelomate
-unsegmented
-no rigid cuticle
-bounded by ciliated epidermis
-move by ciliary movement and ms squeezing
-anterior end sense organs. (eyes, brain)
PROTONEPHRIDIA

Question 31

protonephridia

Answer 31

excretory ducts made from ectodermal intuckings

Question 32

how do nemertines differ from platyhelminthes?

Answer 32

• proboscis
• the gut has two openings, mouth and anus
• the presence of a closed blood system
• unique cerebral sensory organs
• simple gonads, regularly repeated
• characteristically long and thin, and capable of great changes in length

Question 33

Proboscis

Answer 33

elongated nose or snout.

• separate fluid filled cavity dorsal to the gut
• surrounded by mesoderm
• contract, retract
• food capture
• escape.

Question 34

where would you find the gonads in a nemertea?

Answer 34

regularily repeated between lobes of gut, along the body

Question 35

how do nemerteas sexually reproduce?

Answer 35

dioecious, hermaphroditic

Question 36

greek meaning for Nematoda

Answer 36

thread bearer

Question 37

common name for nematoda

Answer 37

round worms

Question 38

what are the distinctive characters of nematodes?

Answer 38

• slender
• circular in cross-section
• triploblastic
• unsegmented
• enclosed in cuticle
• muscle longitudinal
• no blood or circulatory system

Question 39

describe the cuticle of a nematoda

Answer 39

• many layered structure that is toughed by cross-linked protein chains
• collagen lattice for movement
• extremely resistant both mechanically and chemically
• -deserts, polar regions, digestive enzymes

Question 40

do nematoda have cilia?

Answer 40

nope

Question 41

what shape of muscle do nematoda have?

Answer 41

• longitudinal, not circular

- there are contractile and non-contractile regions

Question 42

what was the first invertebrate to be sequenced?

Answer 42

C. elegans