variations on ancestral themes reading

Question 1

prostomes

examples

Answer 1

nematodes arthopods and oncyohophorans

flatworms annelids and molsucs

Question 2

deuterstomes

examples

Answer 2

hemichordates
echinoderms
chordates

Question 3

urbilateria

Answer 3

common ancestor to bilateria

genes lost by individual phyla in evolution

Question 4

evodevo

Answer 4

evolution and developmental viology balidates thro gene analsis to determine classification

Question 5

drosophila and xenopos

Answer 5

have same hox genes that control antero posterior axis

have chordin bmp gene networks that determines dorsal ventral development

Question 6

prostomes vs deutersomtes

Answer 6

prostomes; mouth at blastophore, mouth first, ventral nerve cord

deutersomes; mouth second, anus at blastopore, dorsal nerve cord

Question 7

prostomes subspecies

Answer 7

ecydozoa and lophotrochozoa

Question 8

ecdysozoa

Answer 8

arthopods nematodes oncyhophorans

Question 9

lophotrochozoa

Answer 9

flatwoms anneilids chordates molluscs

Question 10

snowball earth scneario

Answer 10

glaciation period 550 mya that decreased biological activity and cause selecte bottlenecks, after which radiation of metazoa occured

Question 11

animals evolution

Answer 11

biologically geographically isolated

evolution through genetic evolution

after snowball earth; environment warmed up and intense disepred evolution and gene loss

Question 12

genetic tool kit

Answer 12

urbilateria as common ancestor to bilateria

Question 13

ep lewis

Answer 13

diveored genes control fly ambomdinal segements through colinearity (anterior posterir axis expression)

Question 14

lost genes of urbilateria examples

Answer 14

c elegans and drosohpila lose genes in lophotrochozoa and chordates

Question 15

nematostella vecetensis

Answer 15

sea anmon; cnidarian believed to have diverged from bilateria

Question 16

scott-gehring

Answer 16

discovering homeovox genes

Question 17

homeobox genes

Answer 17

originate in urbliateria

common to grogs and fruit fly developmental genes! all arthopods have similar set

Question 18

mutations and hox genes

Answer 18

mutations cause genes to have different morphological outcomes leading to variation; hence many animal features share historical genetical homologies

Question 19

segmentation in invertebrates

Answer 19

parasegmentation

Question 20

segmentation in vertebrates

Answer 20

segments from sclerotome

Question 21

mouse mesoderm

Answer 21

hox gene xpression correponds to somite borders

Question 22

chordin bmp pathway

Answer 22

dorsal ventral axis
; chordates form CNS from ecoterm and mesoderm forms notochord

xenopus/zebrafish; celldifferentation involve ventral bmp and dorsal chordin genes

Question 23

homologos of chordin dmp in drosophila

Answer 23

dpp and sog gene

Question 24

ancestry of bilaterian cns

Answer 24

in chordates forms dorsally and in prostomes forms ventrally

Question 25

pax6 gene

Answer 25

regulator of eye developmnt

Question 26

hemichordates and pax6

Answer 26

lost neural centralizations secondarily and urblaiters organised CNS

Question 27

genetic toolkit urbilateria

Answer 27

natural seection created diversity but pax 6 genes and hox genes are homolougously brought out by ENVIRONMENTAL constraints causing mutations

Question 28

hox genes and convergent evolution

Answer 28

functional needs (wings of pterodactyls and birds); hence same genes cause the different analogous mutations

Question 29

designated parallellism

Answer 29

converent evolution caused by parallel natraul selection of ancestral gene networks