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Flashcards in animal evolution Deck (67):
1

why are shared embryological characters important

for working out relationshisp

2

gastrulation

formation of gut during embryonic development

3

process of gastrulation

blastula invaginages to form inner and outer layers of ecoderm and endoderm, and in some cases, mesoderm

zygote to 8 cell stage to blastula to gastrula

4

blastula

hollow ball of cells that gastrulates to form the ectoderm and endoderm

5

achenteron

ancient gut cavity

6

radial celavage example

sea urchins strongylocentrotous purpuratus

7

spiral cleavage example

maritigrella crozier

8

cleavages in deuterostomes

radial

9

cleavages in protostomes

spiral

10

triploblasts properties

have 3 cell layers (endoderm, ecoderm, mesoderm)
have a through gut
seperate mouth and anus
bilateraially symmetrical (dorsal and ventral)

11

what does the mesoderm become

muscles blood bone and tissue

12

triploblasts examples

apes clowfnish slug

13

diploblasts properties

2 cell layers [endoderm and ecoderm]

blind gut; allows for food and wate to pass through same opening

gadially symmetrical (oral and aboral axis)

14

what does recent molecular data challenge about triploblasts and diploblasts

1) whether cnidarians only have two tissue layers
2)whether chindarisn are actually radial symmetrical

15

cnidarians and 2 tissue layer

stienmetz; gut like ectodermal tissue (pharygeal endoderm) present in sea anemon challenges germ layer homology

middle cell layer; maybe differentiate differently but present in both; challenges view that ectoerm is homolougous with animals

16

cnidarians and radial symmetry

genes show that bottom has different genes than in the top of cnidarians even though they LOOK radially symmetrical

17

radial symmetry

cleave during which the cleavage planes are either parallel or perpendicular to the vertical axes of the embryo

18

spiral cleavage

cleave in which the planes of cell deivision are diagonal to the certical axes of the embryoo

19

TRIPLOBLASTIC VARIATIONS

ACOELOMATE

PSEUDOCEOLOMATE

COELOMATE

20

acoelomate

meants without

an extoder, without solid mesoderm, endoderm

e.g. flatworms like platyhelminth

21

pseudocolomate

mesodemr has a cavity

e.g. nematode (fluid filled space)

22

coelomate

mesoderm has epitlial lined cavaity
e.g. vertebrates and annelids

23

ecdysis

moutling ot cuticle with growth like in scorpions or priapulid worms

24

segmentation

repeated units of construciton along anteroposterior axis like annelids

25

opisthokonts

'rear facing flagellum'; animals such as fungi, choanoflagallets an dother

the closest clade to animals; include fungi and choanolglatallets


all have posterior flagellum

26

what to animals and opisthokonts share

an additional amino acid in elongation factor one alpha rpoteins resuting in sperm cell having a posterior flagellem

27

anterior flagellum

euglena

28

sponges

animals
collage
multicellular
seperate junctions
spermatozoa;

similar unicellular complexes like choanoflgallates such as choanocyte cells inw ater that filter feed by creating currents to suck water in

29

first sign of life

1 billion years ago

30

twitya formation

canada; 610 mya

31

ediacaran fossils

named after ediacara history of australia

sedimentary rocks that used to be uniceliar

32

vendian

what russians called the ediacarn fossils on the winter coast

33

origins of ediacaran fossils

carbonate layer appeared post-ice age

34

why do scientists think ediacarans are snimals

similar to animal fossils in youner proterozoic rocks

formed in deep water

not carbon preserved; impressions hence not made by plants

simplest metazoans living today are sea anomons, corals and jellyfish that resembl them

35

porifera and ediacara


similar structures to ediacaran sponges
all sponges have splerocytes which take in minerals from water for agility and strength


e.g. hexactinellida and paleophramodicta

36

cnidarians and ediacara

even more similar to modern fossils

e.g. dickinsonia

e.g. carnia

37

protostomes

ecydsozoa and lophotrophozoa

38

diploblasts

cetenophores cnidarians

39

what are ctenophora

sea goosebeeries or comb jellies

big creatures with ''corn rows' (compound cilia)

are predators; tenteacles or telophores catch fish

mroe complex than sponges

40

trichoplax adhaerans

placazoa phlyum; diploblasts

more simple than cnidarisn but closer realted ot us; more complex ancestors probabled symplified

tricho= hair plate
have 4 cells

reprdocue by sex for genetic mixture (no one has seen egg or sperm) AND binary fission

share features with metazoas (complex genetic pathways)

41

earliest evdiecne for triploblasts

more complex movement and activity

produce trace fossils

appear suddenly in fossil record

many different groups

42

lack of evidence of cambrian evidence before explosion?

minute animals
cryptic animals
arose quickl after instaed

43

triploblastic ediacaran fossils

spiriliginna (became arthopod)

tribachinidium (became echinoderm)

kimbella (became mollusc)

44

cambrian explosion

increase in oxygen levels

end of snowball earth and genetic bottle necks caused diversification

calcium from midearth ridges allowed for skeletons of calbium carbondate to be made

genetic and developmental invetion such as hox genes

predator prey arms race

45

hox genes...?

patern anteror posterior axis developments

46

who discovered the burgess shale

charles doolittle walcrot; his horse opened a rock with a fossil

47

cambrian fossils examples

lopopod

marelia

sanctacrans

pikalia

wiwaxia

opabina

hallucidengia

48

opabina

has a long flexible probisics with grasping spines; resulted in laughter when presented in converence

49

lophotrophozoa

flatworms
molluscs

annelids


lophphorates

50

ecdysozoa

nematods and arthopods

51

deuterstome properties

radial and intermediate cleavage


enterocoleous formation of colelom (folds of archeteron from coleom)

anus develops from blastorpore

mouth derives from second opening in embryo

52

protostome properties

spiral and determine cleavage

schizocoleous coelom formation (soilid masses of mesoderm split to form colelom)

mouth develops from blastopore

mouth derives form first opening

53

parazoa

sponges; no tissues

54

radiata

cnidarians and ctenophorans; radial symmetry

55

lophotrocohoza

grow by increasing body mass, locomotion and trochophore larvae

56

tree of life...

not ladder of life (hierarchy is bad and there is not top of evolutionary tree)
its not a progression; common ancestors are basel

57

basal and primitive

- refer to primitive common ancestors, not current species as direction of evolution is derived from ancestry
hence fossils basal to living groups

58

homologoy summary

common traits due to common descent such as legs

animals with legs are parismonions and closly related

homology of genes easier to determine (e.g. hox4 mous and drosphpila gene)

ancestral homolougs characters as synamophories hence informative and determine ingroups

59

analogy summary

convergent evolution

dorsal fin of sharks and dolphins for example indepent (fish and mammals are different species)

60

mithoncdrial gene order and synanomorphy

crustceans and insects have similar red gene

centipedes and spiders have this red gene seomewhere else

61

homoplasy

similarity due to convergent evolution ; placing analogous species together on assumption they are homologous

62

example of homoplasy

tansmian wolf (now extinct) and wolf where placed together due to hunter, jaws, and skulls but in reality wolf more closely related to kangaroo and tasmainan wolf is a marsupial more closely related to human

63

character loss and phylgentic confusion

converges happens or characters are lost than can cause confusion

64

whale and shark

whales more related to cows but whales have retired to sea; thought to be related to sharks; not true

65

urochordates (seasquirts) and molluscs

sea squirts are actually more closely related to fish but lose traits to become sessile filter feeders

66

hierarchy misconception of animal evolution

diploblasts to acoelomates to pseudomates to coelomates

67

truth about hierarchy misconception of animal evolution

- colemic body and cleaveals is randomly dispered