Intro to Animal Diversity

Question 1

Animal cell extracellular matrix

Answer 1

collagen, other glycoproteins, proteoglycans

Question 2

intercellular junctions only in animals

Answer 2

gap junctions, desmosomes, tight junctions

Question 3

Animal tissue

Answer 3

nervous, muscle. both can conduct electrical signals

Question 4

Common features of early development of animals

Answer 4

blastula-hollow ball of cells

gastrula-blastula with infolded layer of cells

Question 5

Hox genes

Answer 5

animals have. contain homeoboxes and homeotic in function. function during development to specify features of animal’s body plan. products determine developmental fate of groups of cells

Question 6

homeobox

Answer 6

180bp sequence of DNA, encodes for homeodomain of protein: 3 alpha-helices that can bind to DNA, can bind to major groove of DNA

Question 7

homeodomain

Answer 7

60amino acid

Question 8

homeotic gene

Answer 8

gene determining placement and identity of body parts

Question 9

transcription factors

Answer 9

regulators of transcription of genes

Question 10

Variation in Hox gene activity

Answer 10

leads to variation in animal body plan. evolutionary significance to understand diversification of phylum and class. Evolutionary development

Question 11

Parazoa

Answer 11

no tissue, some weak cell specialization. eg. sponges, placozoans

Question 12

Eumetazoa

Answer 12

tissues

Question 13

Radial symmetry

Answer 13

oral-aboral, often sessile or planktonic (drifting). threats/opportunities from all directions

Question 14

Diploblastic

Answer 14

2 germ layers (ectoderm and endoderm)

Question 15

Bilateral symmetry

Answer 15

have 3 germ layers, applies to most animals. Clade Bilateria. anterior-posterior. dorsal-ventral. right-left. cephalization. suited for active forms, encounter world from one direction

Question 16

Triploblastic

Answer 16

3 germ layers: ectoderm, mesoderm, endoderm. All protostomes and deuterostomes are triploblastic

Question 17

Determinate cleavage

Answer 17

early cleavage products lose ability to form completely embryos by themselves

Question 18

Indeterminate cleavage

Answer 18

early cleavage products can form completely embryos by themselves

Question 19

Protostome development

Answer 19

spiral and determinate 8-cell stage, solid masses of mesoderm split and form coelom, mouth develops from blastopore

Question 20

Deuterstome development

Answer 20

radial and indeterminate eightcell stage, folds of archenteron form coelom, anus develops from blastopore

Question 21

coelomate

Answer 21

coelom is lined with mesoderm (muscle) only. can be large and more active than acoelomates

Question 22

pseudocoelomate

Answer 22

pseudocoelom is lined with endoderm and mesoderm

Question 23

acoelomate

Answer 23

no coelom, mesoderm forms a solid mass of cells

Question 24

functions of coleom

Answer 24

space for organ development
cushions organs and allows movement of organs
allows development of a blood vascular system
can serve as a hydrostatic skeleton
separates gut muscles and body wall muscles.

Question 25

last common ancestor of animals

Answer 25

colonial protist, 800-675 mya

Question 26

animal near-relations alive today

Answer 26

choanoflagellates, collar cells. signalling, adhesion molecules

Question 27

stimulation of early animal evolution

Answer 27

end of Snowball EArth phase, 830-635 mya

Question 28

Doushantuo fossils

Answer 28

approx 600-570 mya, look like animal embryos. cells became small as they became more numerous

Question 29

Ediacarans

Answer 29

585-542 mya, first large multicellular organisms. looked like sponges, cnidarians, molluscs, echnioderms, worm tracks, nothing else

Question 30

Cambrian explosion

Answer 30

542-525 mya, half of animal phyla on EArth today were represented. many basic body plans appeared and many diversified. basic body plan=phylum

Question 31

Burgess shale

Answer 31

key fossil formation, 505 mya, soft parts of organisms preserved

Question 32

Why did Cambrian explosion happen?

Answer 32

new predator-prey relationships, new weapons, new defences, new modes of locomotion, new senses-eyes. rise in atmospheric O2-support more active metabolism. evolution of Hox genes-great variability=greater morphological variation