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n ma

vers ca on

o ay sques ons:

I. W atarean ma s

II. Howdid

body

plans

change

as

animals

vers e

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I. Whatareanimals?

Feedingandmoving

mac ines

phylogeny

Epithelium

Ecto/endoderm

Mesoderm

Diploblast

Triploblast

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II.Howdidbodyplanschangeasanimalsdiversified?

A.

Multicellularity and

tissuesAllanimalsaremulticellular

Cellsbindtoeachother

Cellscommunicate

Divisionoflabor(somecellsfunctioninfeeding

vs.structurevs.reproduction)

Multicellularity evolvedindependently

in

fungi,

plants,andseverallineagesofalgae.Aretheprocesses

abovesameordifferent?- Homoplasy due to independent evolution.- As such, there is likely to be variation between the traits.

- Different traits to serve same function.

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Originoftissues

(integratedgroupsof

cellsthatperformaparticularfunction)

Whereto

map

origin?

Tissues

c o erm

Endoderm

Mesoderm

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B.Bodysymmetryandcephalization

Classically:

Radialsymmetryindiploblasts

Bilateralsymmetryintriploblasts

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y y

w

z :

1)centralizedneurons;2)ganglia(brain)+sensoryorgans

Posteriorregionspecializedfordigestion,reproduction,

locomotion adaptivesignificance?

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Reversiontoradialsymmetryinechinoderms

en ara a symme ry na u s ; arvaeare a era y

symmetric

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C.Evolutionofabodycavity(coelom)

Functions:

Hydrostaticskeletonimportantinmovement

,

Tubewithin

atube

body

design

Water being squished will force it into another area, forcing movement

in that direction.

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D.Developmentalpatterns

Classicall :

1. Protostome development Spiralcleavage

Coelom frommesoderm

blocks

2.Deuterostome development

Radialcleavage

Mouthsecond

gastrulation

Coelom frompinchedoff

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E.Segmentation

Repeatedstructuralunitsinabody:annelids

(segmentedworms),arthropods,vertebrates

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F.Growthpatterns

continuousgrowth

e amorp os s

No competition between them since

they use different resources.

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Questions:

1. Areannelidsmore

derivedthansponges?

2.Whichanimalsare

basal?

3.Islossofthecoelom in

mollusks,echinoderms,

and

chordateshomologous?

No animals is really more derived than

another.

Homoplasic, ancestor of mollusk had coelom.