bio212 w03

Question 1

acoelomate

Answer 1

lacking a body cavity (ex: flatworms)

Question 2

body plan

Answer 2

an assemblage of morphological features shared among many members of a phylum-level group; aspects: symmetry, segmentation, limb disposition

Question 3

coelom

Answer 3

fluid-filled body cavity derived from mesoderm, lined by mesodermal epihtelium; shock absorption; hydrostatic skeleton; allows muscles to grow independently off body wall

Question 4

Clade

Answer 4

a group consisting of an ancestor and all its descendants; aka monophylum

Question 4

schizocoelomate

Answer 4

Describes how the body cavity develops in protostome animals by splitting of mesoderm buds to form sacs.

Question 5

Mullusca

Answer 5

phylum of invertebrate animals; largest marine phylum;

three main features:
- a mantle with a significant cavity for breathing/excretion

• a radula - finely toothed, chitinous ribbon for scraping/cutting food before it enters the oesophagus; in all but bivalves
• the structure of the nervous system

Question 7

trochophore

Answer 7

free-swimming planktonic marine larva (of trochozoan clade), w/ several bands of cilia, used to control movement or bring food closer;

Question 8

exoskeleton

Answer 8

a hard encasement on the surface of a animal, such as the shell of a mollusc or the cuticle of an arthropod, that provides protection and points of attachment for muscles

Question 9

open circulatory system

Answer 9

a system in which an open cavity called a hemocoel baths the organs directly with oxygen & nutrients; blood + interstitial fluid = hemolymph

Question 10

water vascular system

Answer 10

a network of hydraulic canals unique to echinoderms that branches into extensions called tube feet, which function in locomotion and feeding.

Question 11

Nematoda

Answer 11

“roundworms”; parasitic -> aquatic -> terrestrial; bilateral, triploblastic, pseudocoelomate (only!); 1st to have mouth & anus *tube within a tube”;

Question 12

Porifera

Answer 12

simplest multicellular animals, lacking distinct tissues or structures. Simple body plan of two cell layers around central cavity (spongocoel). Unique flagellated cells (choanocytes) move water in via small holes (ostia), and out through large hole (osculum).

Question 13

radial symmetry

Answer 13

symmetry in which the body is shaped like a pie or barrel (lacking left/right), and can be divided into halves by any plane through central axis

Question 14

mesoderm

Answer 14

the middle primary germ layer in triploblastic animal embryo; develops into notochord, lining of coelom, muscles, skeleton, gonads, kidneys, and most of circulatory system

Question 15

Arachnida

Answer 15

.

Question 15

protostome

Answer 15

.

Question 16

enterocoelom

Answer 16

.

Question 17

chitin

Answer 17

.

Question 18

bilateral symmetry

Answer 18

.

Question 19

Chordata

Answer 19

.

Question 21

Cnidaria

Answer 21

• generally radially symmetric
• diploblastic: two true tissue layers (epidermis/gastrodermis), separated by gelatinous matrix (mesoglea).
• named for cnidocytes, cells containing stinging organelles (nematocysts)
• two body forms: medusas and and polyps

Question 22

Annelida

Answer 22

segmented worms; bilateral, triploblastic, ceolomate (1st true coelom);

Question 23

endoderm

Answer 23

the innermost of germ layers in animal embryo; lines archenteron and fives rise to liver, pancreas, lungs, and lining of digestive tract

Question 24

deuterostome

Answer 24

“mouth second”, because blastopore form anus first

Question 24

cuticle

Answer 24

an outer skeleton of all ecdysozoans that protects the body and is periodically shed as the animal grows (ecdysis)

Question 25

spiral cleavage

Answer 25

in protostomes: planes of cell division are diagonal to vertical axis; adjacent new cells sit on grooves of previous cells

Question 26

cephalization

Answer 26

.

Question 28

cephalization

Answer 28

an evolutionary trend towards concentration of sensory equipment at the anterior end of the body

Question 29

Vertebrata

Answer 29

animals with backbones

Question 30

Platyhelminthes

Answer 30

“flatworms”; ex: planarian, tapeworm, fluke; bilateral, triploblastic (1st!), acoelomate

Question 31

pseudocoelomate

Answer 31

animal with body cavity derived from both mesoderm & endoderm

Question 32

Ecdysozoa

Answer 32

class of protostomes that grow exoskeletons and lack surface cilia in both larval and adult stages.

Includes nematodes and athropods (the most diverse animal phylum)

Question 32

Lophotrochozoa

Answer 32

clade linked by molecular data; includes organisms that have lophophores or trochophore larvae

Question 33

ectoderm

Answer 33

outermost of 3 primary germ layers in animals; gives rise to outer covering, and in some: nervous system, inner ear, lens of eye

Question 34

Chelicerata

Answer 34

Lineage of Arthropoda. Name reflects claw like feeding appendage: chelicerae. Body has anterior cephalothorax and posterior abdomen. Includes horseshoe crabs, mites, spiders, scorpions, and ticks. Lack antennae, compound eyes, and jaw like mandibles of other lineages.

Question 35

radial cleavage

Answer 35

type of embryonic development in deuterostomes in which planes of cell division are either parallel or perpendicular to vertical axis of embryo, aligning tiers of cells above one another

Question 37

Echinodermata

Answer 37

phylum of marine animals, recognizable by their (usually five-point) radial symmetry, and include such well-known animals as starfish, sea urchins, sand dollars, and sea cucumbers.

Question 38

lophophore

Answer 38

Feeding structure consisting of ciliates tentacles.

Question 38

Cephalochordata

Answer 38

chordate sub-phylum defined by the presence of a notochord that persists throughout life

Question 39

Urochordata

Answer 39

.

Question 40

spongocoel

Answer 40

central cavity of sponges (Porifera)

Question 41

choanocytes

Answer 41

cells w/ flagella, found only in phylum Porifera (sponges), move water in through pores on body surface (ostia) and out through large opening (osculum)

Question 42

3 ways deuterostomes differ from protostomes

Answer 42

• radial instead of spiral cleavage
• enterocoelous body cavity dev. instead of schizocoelous
• genetic similarities indicate closer relationship among themselves than to taxa group in protostome phyla

Question 43

sessile

Answer 43

attached to a substrate