glossary

Question 1

eumetazoa

Answer 1

The ‘true’ animals; excludes the Porifera

Question 2

coelenterates

Answer 2

A paraphyletic group containing the Cnidaria and the Ctenophora; diploblastic

Question 3

Bilateria

Answer 3

Animals with bilateral symmetry

Question 4

Protostomia

Answer 4

Animals where the blastopore becomes the mouth; spiral cleavage; schizocoelom

Question 5

Ecdysis?

Answer 5

Shedding of the outer integument, usually as part of growth

Question 6

Ecdysozoa?

Answer 6

Protostomes that grow by shedding their outer integument (=ecdysis)

Question 7

What are Spiralia?

Answer 7

Protostomes that do not grow via ecdysis

Question 8

What is Gnathifera?

Answer 8

Spiralians with complex jaws made of chitin

Question 9

Define Lophotrochozoa

Answer 9

Spiralians which have both a lophophore and a trochophore larva

Question 10

What is Deuterostomia?

Answer 10

Animals where the blastopore becomes the anus; radial cleavage; enterocoelom

Question 11

What are the key characteristics of Chordata?

Answer 11

Deuterostomes that possess a notochord, a hollow dorsal nerve cord, an endostyle, pharyngeal slits, and a post-anal tail

Question 12

What does Ambulacraria include?

Answer 12

A deuterostome group including the echinoderms and hemichordates

Question 13

What is an Apomorphy?

Answer 13

A new trait that has evolved from an ancestral species

Question 14

Define Blastomere

Answer 14

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

Question 15

What is a Blastopore?

Answer 15

The point where the blastula invaginates to create the gastrula

Question 16

Define Blastula

Answer 16

Early stage of embryonic development, a hollow ball of cells

Question 17

What is a Coelom?

Answer 17

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

Question 18

What does Dioecious mean?

Answer 18

Having male and female reproductive organs in separate individuals; gonochoric (synonym)

Question 19

What is the definition of Hermaphrodite?

Answer 19

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

Question 20

What is a Lophophore?

Answer 20

A ring-shaped or horseshoe-shaped organ surrounding the mouth which has ciliated tentacles for food capture

Question 21

What does Metameric refer to?

Answer 21

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

Question 22

Define Monophyletic group

Answer 22

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

Question 23

What is a Paraphyletic group?

Answer 23

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

Question 24

What characterizes a Polyphyletic group?

Answer 24

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

Question 25

What is a Plesiomorphy?

Answer 25

An ancestral trait present in a particular taxon

Question 26

Define Protoandry

Answer 26

A type of sequential hermaphrodite which begins male and later becomes female

Question 27

What is Protogyny?

Answer 27

A type of sequential hermaphrodite which begins female and later becomes male

Question 28

What is Radial cleavage?

Answer 28

Developmental process where the blastomeres are arranged directly above each other

Question 29

Define Schizocoelom

Answer 29

A coelom that develops from a split in the mesoderm; found in the Protostomia

Question 30

What is Spiral cleavage?

Answer 30

Developmental process where the blastomeres are arranged in a spiral pattern around the embryo's axis

Question 31

What is a Synapomorphy?

Answer 31

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

Question 32

Define Tagma

Answer 32

A grouping of metameric segments into a coherently functional morphological unit (plural tagmata). E.g. head, thorax, abdomen

Question 33

What does Taxon refer to?

Answer 33

A monophyletic group

Question 34

What is a Trochophore larva?

Answer 34

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