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