Evolution of body plans

Question 1

Body plan

Answer 1

Basic structural design of a particular animal group

Question 2

Symmetry

Answer 2

Asymmetric (0), radially symmetric (any plane along main body), bilaterally symmetrical (1)

Question 3

Synapomorphy

Answer 3

Shared derived trait. Basis for phylogenetic (may be convergent evolution). molecular phylogenetic also used

Question 4

Traits supporting monophyly of animals

Answer 4

Multicellular, single-celled zygote, heterotrophic, contractile muscles, gene sequences, Hox gene function, cell junction similarity, ECM - collages, proteoglycans

Question 5

Simple: placozoa

Answer 5

1mm diameter, marine, multicellular, simple epithelium enclosing loose sheet of stellate cells, bear flagella to crawl along sea floor

Question 6

Types of simple

Answer 6

Placozoa, porifera (sponges), etnophora (comob jellies), cnidaria (hydrozoans, sae anemones, jelly fish, corals_

Question 7

Germ layers of embryo: one layer

Answer 7

Placozoa, porifera

Question 8

Germ layers of embryo: two layers

Answer 8

Diploblastic - endo/ectoderm: ctenophora, cnidaria

Question 9

Germ layers of embryo: three layers

Answer 9

Triploblastic - endo/meso/ectoderm: protostomes and deutersotomes; coelomate, pseudocoelomate, coelomate

Question 10

Protostomes

Answer 10

Embryonic blastopore -> mouth, radial cleavage ancestral, asymmetric, some spiral cleavage, bilaterally symmetrical, entrance to digestive tract anterior to brain, ventral NS, circulatory system missing or open/closed. 2 classes and 1 unclassified group

Question 11

Protostomes: lophotrochoza

Answer 11

Grow by adding to skeleton - lophopre structure for feeding, internal hydrostatic skeleton
Phylum byozoa: marine, sessile, colonial, feed using lophophores and beating cilia on tentacles, AS and sometimes filler feeders
Other phylums: photon, brachiopod, platuhelminthes (flatworms), rotifera, nemertea (ribbonworms), annelida (classes: oligochaete, polychaeta, hiradinea), mollusca

Question 12

Protostomes: chaetognartha (arrow worm)

Answer 12

Phylogeny debated, sister group to lophotrochozoa?, marine, planktonic, column, no trochophore larvae, no circulatory system

Question 13

Protostomes: ecdysozoa

Answer 13

exoskeleton, moulting, grow ecdysis - ways to feed

Phyla: nematoda (roundworms), onchophora (velvet worms), chelicerata (spiders), crustacea, myriapoda, hexapoda

Question 14

Deuterostomes

Answer 14

Embryonic blastopore => anuc, radial cleavage

Question 15

Deutrostomes: phyla

Answer 15

Echinodermata, hemichordata, chordata (classes: urochordata, cephalocordata - subphylum vertebrata)

Question 16

Paratism

Answer 16

Non-metal relative organisms - benefits at cost of other

Question 17

Ectoparasite

Answer 17

Lives on surface of host

Question 18

Endoparasite

Answer 18

Lives within host

Question 19

Parasitoid

Answer 19

Organism spends most of life in single host and kills host

Question 20

Pathogen

Answer 20

Organisms causing disease in host

Question 21

Vector

Answer 21

Organism transmits pathogen e.g. anopheles mosquito carries malaeria

Question 22

Platyhelminthes: classes

Answer 22

Monogenea - skin flush - hooks for attaching; trematoda - endoparasites with complex life cycles - 2 replication life stages - snail fever, snail and vertebrate host; cestoda (tape worms) - vertebrate - no gut, feeds by absorbing part-digested carbohydrate to inhibit host digestive enzymes; nematoda - mouth -> buccal cavity, many have teeth, muscular pargynx, grow by malting (ecdyosozoan), many larval stages; crustacea - copepoda and cirripedia (barracks) - ectoparasites