evolution and diversification of life• earth formed about 4.5 billion years ago (bya) and crust...

Evolution and Diversification of Life

OCN 201 Science of the SeaBiology Lecture 2

Frogfish

Grieg Steward (Oceanography) Office: CMORE Hale 121

Phone: x6-6775

Sunday, November 9, 2014

Evolution

Nothing in biology makes sense except in the light of evolution - Theodisius Dobzhansky

I am a creationist and an evolutionist. Evolution is God's, or Nature's method of creation. Creation is not an event that happened in 4004 BC; it is a process that began some 10 billion years ago and is still under way. - Theodisius Dobzhansky

Sunday, November 9, 2014

• Heritability of traits from parent to offspring

• Variability among offspring (mutations, recombination)

• Over-production of offspring

• Selection by the environment: Individuals with favorable traits will survive and reproduce more

Basis of Evolution by Natural Selection

Sunday, November 9, 2014

Biological Diversity Arises through Selection

This is not “just a theory”. It is a fact.

Sunday, November 9, 2014

Incomplete Species Separations

donkeyhorse

muleSunday, November 9, 2014

Incomplete Species Separations

False Killer WhaleBottlenose Dolphin

“Keikaimalu”

= Wolphin

+

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Missing Links

Sunday, November 9, 2014

Missing Links

Discovered 2008 (Matt Friedman)

Sunday, November 9, 2014

• Prokaryotes (no nucleus)

• Bacteria

• Archaea

• Eukaryotes (with nucleus

A Fundamental Division

DNA

DNA

DNA

and other internal compartments)

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PhotosyntheticEukaryote

• Eukaryotes arose through the merger of multiple prokaryotic cells

Serial Endosymbiosis Theory

Eukaryote

Animals

PhotosyntheticBacteria

Plants

Archaea

Anaerobic Bacteria

AerobicBacteria

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Origins of Animals

Unicellular

Colonial

Multicellular

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Origins of Plants

Unicellular

Colonial

Multicellularmarine alga terrestrial moss

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Protista

Prokaryotae

Single CellEukaryotes

Prokaryotes

MulticellularEukaryotes

Animalia

Plantae Fungi

The Traditional Five Kingdoms

Sunday, November 9, 2014

Life is a Messy BusinessSymbioses and Horizontal Gene transfer Contribute to the Diversity We See

It is a web of life as much as a tree of life

Sunday, November 9, 2014

Evolution

• Evolution is not uni-directional

• Simple things came first

• Complexity accumulates slowly through trial and error via many known mechanisms

• The simple and the complex continue to co-exist

• As the earth changes, species die off and new ones emerge

Sunday, November 9, 2014

Classification of Life• The vast diversity of life makes sense when considered in

the light of evolutionary history

• The splitting of one species into two leads to a nested hierarchy of characteristics that can be shown as a branching tree

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Hierarchical Classification

• Species

• Genus

• Family

• Order

• Class

• Phylum

• Kingdom

• Domain

vulgaris

Octopus

Octopodidae

Octopoda

Cephalopoda

Mollusca

Animalia

Eukarya

Orcinus

orca

Delphinidae

Cetacea

Mammalia

Chordata

Animalia

Eukarya

delphis

Delphinus

Delphinidae

Cetacea

Mammalia

Chordata

Animalia

Eukarya

CommonOctopus

OrcaBottlenosedolphin

Sunday, November 9, 2014

Protista

Plantae

Animals

Fungi

The Old Five Kingdom View of Life

Monera

Macroscopic organisms

disproportionatelyrepresented

Sunday, November 9, 2014

The History of an Organism is Written in its DNA

• But how do we interpret it?

• Can use changes in DNA sequence over time as a “molecular clock”

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Sequence ComparisonsDiversity and evolutionary relationships

Seq. A ATACGGTCAC..Seq. B ATTCGCTCAC..Seq. C ATGCGGTCAC..

A

C

B

1 22 G

A B CA 2 1B 2 2C 1 2

Pairwise comparisons of sequences to count nucleotide differences

Summarize differences in a distance matrix

Build tree which satisfies the observed distance relationships

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Eukaryota

The Three Domains of Life

Prokaryotes Eukaryotes

and two cell types

Domain

Domain Domain

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• Earth formed about 4.5 billion years ago (bya) and crust solidified 4.1 bya

• Mineral deposits, thought to be produced only by biological activity, dated at 3.8 bya

• Fossils resembling present-day mats of marine microorganisms found at 3.5 bya

First Evidence of Life

Sunday, November 9, 2014

Fossil Stromatolites Modern Stromatolites

Sunday, November 9, 2014

Timeline

First Prokaryotes >3500

Photosynthetic Prokaryotes 2500

Eukaryotes 1000

Invertebrates 700

Vertebrates 500

Land Plants 430

Mammals 190

Apes 7

Humans 2.5

You 0.00002

(millions of years ago)OrganismFirst appeared

Sunday, November 9, 2014