Lecture 11
• Evolution and Development
• Animal development
• Phylogenetics: terms and analysis
Evolution: explanation for the diversity of life/form.
Development: generation of form.
Evo Devo is the synthesis of these.
General animal life cycle
Soma
Germ-line
fertilization fertilization
Somatic germ-linedivision
Animal development
Sperm
Egg
Zygote
Gametes
Development
Origins of multicellularity
Willmer Invertebrate relationships
Implicit phylogenys
Primordial ooze
worm
rat
chimp
human
Primordial ooze
human chimp rat worm
time
Metazoan origins
Three techniques used
A) examine living organisms
B) examine the fossil record
C) examine DNA sequence
Metazoan origins
Considerations when looking at the living
A Divergence vs convergence
Metazoan origins
Considerations when looking at the living
A Divergence vs convergence
Human and Squid camera eyes
Metazoan origins
Considerations when looking at the living
A Divergence vs convergence
B Polyphylogeny vs monophylogeny
Metazoan origins
Polyphylogeny vs monophylogeny
Polyphylogeny independent evolution of a characteristic
Monophylogeny common ancestry
Evolution of a chitin exoskeleton
Polyphylogeny Monophylogeny
Proto-platyhelminthes
No exoskeleton
Insects Crustacea Spiders Insects Crustacea Spiders
Common ancestor with an exoskeleton
Metazoan origins
Considerations when looking at the living
A Divergence vs convergence
B Polyphylogeny vs monophylogeny
C time blurs all origins
Metazoan origins
Considerations when looking at the living
A Divergence vs convergence
B Polyphylogeny vs monophylogeny
C time
D data set in the present
First metazoans
Willmer Invertebrate relationships
Pseudoceolomates
Willmer Invertebrate relationships
Worms
Willmer Invertebrate relationships
Mollusks
Willmer Invertebrate relationships
Arthropods
Willmer Invertebrate relationships
Deuterostomes
Willmer Invertebrate relationships
Organization of the major animal groups
Raff The shape of life
Organization of the major animal groups
Raff The shape of life
Organization of the major animal groups
SpongeMulticellularMultiple cell typesNo organized tissues
Raff The shape of life
Organization of the major animal groups
DiploblastOrganized tissuesDiploblastic ectoderm/endodermNeuron-no CNSSensory cells-no PNS
Raff The shape of life
Organization of the major animal groups
AcoelomateTriploblastic: ecto meso endodermsSingle gut openingBilaterally symmetric, A/P axisOrganized CNS and PNSNo body cavity
Raff The shape of life
Organization of the major animal groups
PseudocoelomatesOne side of the body cavity lined with mesoderm
Raff The shape of life
Organization of the major animal groups
EucoelomatesBoth sides of the body cavity lined with mesodermHydrostatic skeletonCirculatory system
Raff The shape of life
Proposal for animal phylogeny
Willmer Invertebrate relationships
Fossils
When do we see the first fossil animals?
Cambrian Ediacaran Cryogenian
Marinoan Sturtian
500Mya 600Mya 700Mya
Porifera
Snowball Snowball
First fossils found
Fossil sponges 640-650 My old
Cambrian Ediacaran Cryogenian
Marinoan Sturtian
500Mya 600Mya 700Mya
Porifera
Snowball Snowball
First fossils found
Cambrian Ediacaran Cryogenian
Marinoan Sturtian
500Mya 600Mya 700Mya
Porifera
Snowball Snowball
First fossils found
Burrow trace fossils
Surface trace fossils
Trace and body fossils
Carroll et al., From DNA to diversity
Cambrian Ediacaran Cryogenian
Marinoan Sturtian
500Mya 600Mya 700Mya
Porifera
Snowball Snowball
First fossils found
Burgess
Chengjiang
Doushantuo
Lantian
Avalon
Lantian and Avalon Biota
Ediacarans: soft body preservation
Raff The shape of life
Cambrian Ediacaran Cryogenian
Marinoan Sturtian
500Mya 600Mya 700Mya
Porifera
Snowball Snowball
First fossils found
Burgess
Chengjiang
Doushantuo
Lantian
Avalon
Fossilized embryosOver 550 million years old
Doushantuo
Doushantuo
Bacteria and not embryos?
Cambrian Ediacaran Cryogenian
Marinoan Sturtian
500Mya 600Mya 700Mya
Porifera
Snowball Snowball
First fossils found
Burgess
ChengjiangDoushantuo
Lantian
Avalon
Chengjiang
Burgess shales
Burgess shales
Soft body preservation
Regular preservation
Cambrian Ediacaran Cryogenian
Marinoan Sturtian
500Mya 600Mya 700Mya
Porifera
Snowball Snowball
First fossils found
Porifera Biomarker
Biomarkers
Biomarkers
DNA sequence analysis
Organism 1 ATGTCCGTGAGTCGTCGTAGCTGATOrganism 2 ATGTCCGTGAGTCGTCGTAGCTGATOrganism 3 ATGTCAGTGAGACGTCGTAGCTGATOrganism 4 ATGTCAGTGAGTCCTCATAGCTGATOrganism 5 AAGGCCGTGAGACCTCATAGCTGAT
rRNA 18S analysis
Raff The shape of life
Choanoflagellates
Cambell Biology
Choanoflagellates
Cambell Biology
GENOME SEQUENCE RECENTLY COMPLETED
Traditional phylogeny based on the coelum
Traditional phylogeny based on the coelum
Simple to complex
DNA analysis tells a different story
Pseudocoelomy is polyphylogenic
Priapulids Nematodes Rotifers
coelomates
H Philippe et al. Nature 470, 255-258 (2011) doi:10.1038/nature09676
Animal phylogeny based on mitochondrial proteins reconstructed using theCAT+GTR+ Г model under a Bayesian analysis
DNA analysis tells a different story
Complex to simple
Odontogriphus reburrus: early lophotrochozoan
Morris and Caron Science 315, 1255
JN Liu et al. Nature 470, 526-530 (2011) doi:10.1038/nature09704
Reconstruction of Diania cactiformis in dorsolateral view.
Jointed armored velvet wormTransitional form. 520Mya
Base groups
Complex to simple
Problem with sponges: complex to simple?
0
300
600
900
1200
Protostome/Deuterostomesplit
Chordata ChordataMullusca Mullusca
Cambrian
Vendian
Molecular clock analysis
0
300
600
900
1200
ChordataMullusca
Cambrian
Vendian
Molecular clock Biomarker analysis
Protostome/Deuterostomesplit
A complex organism existed at the protostome deuterostome split
Carroll et al., From DNA to diversity
Is the study of living organisms the study of the radiation of Urbilateria?
Carroll et al., From DNA to diversity
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