the evolutionary tree of animals

Question 1

phylogenetic trees

Answer 1

diagrams that depic speciation events

Question 2

speciation

Answer 2

when once species gives rise to two or more daughter species; coined by darwin

Question 3

what did ernst haeckle do?

Answer 3

• created evolutionary trees based on characters in embryology; blieved embryos change slowly in evolution
• similar features found in early development

e.g. jellyfish and sea anemones on branch that pslit early from rest of life

Question 4

non bilaterian symmetry

Answer 4

‘radial’ or ‘no symmetry’

Question 5

bilateral symmetry

Answer 5

near mirror image left and right hand sites

Question 6

what features are used to determine evolutionary trees

Answer 6

• symmetry
• germ layers
• body cavaities
• segmentation
• patterns of cell divion in early embryo

Question 7

phylas with non-bilaterian symmetry

Answer 7

cnidaria (jellyfish, sea anemons, corals,
porifera (sponges)
ctenophora (comb jellies)
placozoa

Question 8

what are germ layers

Answer 8

layers of cells that arise early in the embryo and become more complex later in development

Question 9

triploblasts

Answer 9

• animals with THREE germ layers (mesoderm, endoderm and ectoderm)
• most bilateria

Question 10

diploblasts

Answer 10

nonbilaterieans;

two germ layers; ecotderm and enxodeterm

Question 11

COELOMATA PHYLOGENCY

Answer 11

presence or absence of fluid filled spcaes in the body

Question 12

coelom

Answer 12

• animals (bilaterians) with embryos that have fluid filled spaces lined with an epithelial cell sheet

Question 13

example of coelomate

Answer 13

• annelids,
  echinoderms,
  chordates
  arthopods

Question 14

articulata

Answer 14

‘segmented coelomates’

- placed arthopods and annelids together

Question 15

acoelomate

Answer 15

• bilaterians with SOLID mesoderm and no fluid filled cavitiy

Question 16

acoelomate examples

Answer 16

platyhelminth, nemertea

Question 17

pseudocoleomates

Answer 17

poorly defined body cavaties without epithelia cell layer

–> nemotoda

Question 18

assumption of coelomata phylogency

Answer 18

• the coelomates grouped together and acoelomates spilit of early
• acoelomates thought to be ancestors of coelomates, with pseudoceolomates as hybrid (rise in complexity)

Question 19

groups of bilateria

Answer 19

prostomia and deuterostomtia

Question 20

problem with the coelomata hypothesis

Answer 20

• 1998: (Rudolf Raff and team); evience came to light that there is no supporting evidence of the articulata (using rivosomal RNA geen sequencing)
• segemented annelids and segemented arthopods have different RNA sequeences

Question 21

new animal phylogeny

Answer 21

• four nonbilaterian phyla branch off tree early (germ layers and symmetry good)
• jellyfish, sea anemones, corlas, comb jellis sponies; are basal phyla
• from these the bilateria diverse

biltaeria: not split into acoelomates, pseudocoleumates and coelomates; are all mixed up = no coelomata or articulata grouping

Question 22

new body cavity theory

Answer 22

body cavaties arose more than once in evolution and were ither lost or gaiined

Question 23

what advantage to fluid filled cavaties bring to animals

Answer 23

• provide support to body
• act as incompressible bag against which musscles squeece
• increase power and efficiency of animal movement

Question 24

new bilateria

Answer 24

deuterostomia, ecydozoa and lophotogrphoa

Question 25

deuterostomia

Answer 25

chordata, echinodetermata and hemicordata

Question 26

echinodermata

Answer 26

starfish and sea urchins

Question 27

hemichordata

Answer 27

fould smelling acorn worms

Question 28

ecdysozoa

Answer 28

arthorpoda, nematodoa

Question 29

lophotrophozoa

Answer 29

annelida, mollusca, platyhelmith, brysozoa