zoology key terms

Question 1

apomorphy

Answer 1

new trait that has evolved from an ancestral species

Question 2

blastomere

Answer 2

cells that are created when a fertilised egg divides rapidly during cleavage

Question 3

blastopore

Answer 3

point where the blastula invaginates to create the gastrula

Question 4

blastula

Answer 4

early stage of embryonic development
a hollow ball of cells

Question 5

coelom

Answer 5

fluid filled body cavity of an animal containing the organs
can be a schizocoelom or an enterocoelom

Question 6

enterocoelom

Answer 6

a coelom that develops from the wall of the embryonic gut
found in the deuterostomia

Question 7

schizocoelom

Answer 7

coelom that develops from a split in the mesoderm
found in protostomia

Question 8

dioecious

Answer 8

having male and female reproductive organs in separate individuals
2 sexes

Question 9

hermaphrodite

Answer 9

having male and female reproductive organs in the same individual
may be simultaneous or sequential

Question 10

ecdysis

Answer 10

shedding of the outer integument
usually as part of growth

Question 11

gastrula

Answer 11

early stage of embryonic development
two or three layered cup-shaped embryo

Question 12

lophophore

Answer 12

ring shaped or horseshoe shaped organ
surrounds the mouth
has ciliated tentacles for food capture

Question 13

metameric

Answer 13

animal whose body is divided into segments that are similar (but not necessarily identical) in structure

Question 14

monophyletic group

Answer 14

group of organisms that includes a common ancestor and all of its descendants

Question 15

paraphyletic group

Answer 15

group of organisms that includes a common ancestor and some but not all of its descendants

Question 16

polyphyletic group

Answer 16

group of organisms that share similar traits but do not share a common ancestor

Question 17

notochord

Answer 17

flexide rod of mesodermal origins
found in chordata
precursor to the vertebrae
important in neural development

Question 18

plesiomorphy

Answer 18

ancestral trait present in a particular taxon

Question 19

protoandry

Answer 19

type of sequential hermaphrodite
begins male and later becomes female

Question 20

protogyny

Answer 20

type of sequential hermaphrodite
begins female and later becomes male

Question 21

radial cleavage

Answer 21

developmental process
blastomeres arranged directly above each other

Question 22

spiral cleavage

Answer 22

developmental process
blastomeres arranged in a spiral pattern around the embryos axis

Question 23

synapomorphy

Answer 23

trait present in an ancestral species
shared exclusively by its evolutionary descendants

Question 24

tagma

Answer 24

grouping of metameric segments into a coherently functional morphological unit
plural = tagmata
eg head, thorax, abdomen

Question 25

taxon

Answer 25

a monophyletic group

Question 26

trochophore larva

Answer 26

planktonic larva that has a roughly spherical body
has a band of cilia that allow it to move in a spinning motion

Question 27

diploblastic

Answer 27

2 layers of cells