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Queen Mary U London SBC174/SBS110 Evolution lectures from September 30th. All images are © their respective owners.
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Mini-summary of lectures 1 & 2
Monday, 30 September 13
Specific Questions/Comments
Geologists (Hutton, Lyell):Uniformitarianism: Changes in nature are gradual.
In 1800s, fossils showed species that no longer existed:
Some (e.g. Cuvier): Catastrophism: Fossils show extinct species (due to major, sudden, catastrophic events).
Monday, 30 September 13
3 Schools of evolutionary thought
• Lamarck: characteristics acquired by an individual are passed on to offspring.
• Linneaus: each species was separately created.
• Darwin & Wallace: evolution as descent with modification.
Monday, 30 September 13
Evolution by Natural Selection
• There is inherited variation within species.
• There is competition for survival within species.
• Genetically inherited traits affect reproduction or survival. Thus the frequencies of variants change.
(Not just numbers of offspring!)
Evolutionary fitness:A measure of the ability of genetic material to perpetuate itself in the course of evolution. Depends on the individual’s ability to survive, the rate of reproduction and the viability of offspring.
Monday, 30 September 13
“Neo-Darwinism”or
“The Modern Synthesis”
The same thing... but with better understanding of how things work.
• Darwin’s Theory of Evolution by Natural Selection (1859)• Mendel’s Laws of Heredity (1866, 1900; see SBS 008)• Cytogenetics (1902, 1904 - )• Population Genetics (1908; see Lectures 7-12) • Molecular genetics (1970s- ; see SBS 633/210 and Lecture 6)
•More stuff since then (cultural evolution, epigenetics, etc...)
Monday, 30 September 13
•Evolution also occurs by: • genetic drift• sexual selection• ...
Natural selection leads to adaptive change
•But environmental conditions change: What was advantageous yesterday may be a disadvantage today.
But not all change is adaptive!
Monday, 30 September 13
Paperback 596 pages (11 Aug 2005)
Publisher : Oxford University Press
Monday, 30 September 13
Monday, 30 September 13
1. The Fossil Record
2. Comparative Anatomy
3. Comparative Embryology
4. Vestigial Structures
5. Domestication (artificial selection)
Darwin’s evidence for evolution
Monday, 30 September 13
Geological times & continental drift
Monday, 30 September 13
Today
1. Major transitions in evolution
2. Geological timescales
3. Major geological drivers of evolution
4. Recent major extinction events
Monday, 30 September 13
Major transitions?1.Smaller entities coming together to form larger entities. (e.g. eukaryotes, multicellularity, colonies...)
2.Smaller entities become differentiated as part of larger entity. (e.g. organelles, anisogamy, tissues, castes...)
3.Smaller entities are often unable to replicate without the larger entity. (e.g. organelles, tissues, castes...).
4.The smaller entities can disrupt the development of the larger entity, (e.g. Meiotic drive, parthenogenesis, cancer...)
5.New ways of transmitting information arise (e.g. DNA-protein, indirect fitness...)
Maynard Smith and Szathmary 1995Monday, 30 September 13
Major transitions: early life
1953 Miller-Urey “primitive soup” experiment
350° vs 0°
➔ organic molecules
Monday, 30 September 13
Major transitions: early life
•Organic molecules ≠ Life•Early life:
•Hereditary replication•Compartmentalization
•First hereditary information?
Monday, 30 September 13
Phylogenetic Tree of Life
BacteriaGreen
FilamentousbacteriaSpirochetes
Grampositives
ProteobacteriaCyanobacteria
Planctomyces
BacteroidesCytophaga
Thermotoga
Aquifex
HalophilesMethanosarcina
MethanobacteriumMethanococcus
T. celerThermoproteus
Pyrodicticum
Entamoebae Slimemolds Animals
Fungi
PlantsCiliates
Flagellates
Trichomonads
Microsporidia
Diplomonads
Archaea Eukaryota
last universal common ancestor (LUCA)
Woese 1990 tree based on ribosomalRNA sequencesMonday, 30 September 13
Major transitions: early life
•Organic molecules ≠ Life•Early life of simple replicators:
•Hereditary replication•Compartmentalization
•First hereditary information?•Probably RNA: Genetic information (that can be copied)
+ Enzymatic activity.
•Amino-acids (initially as co-factors)•DNA (much more stable than RNA)•Linkage of replicators (chromosomes)
Monday, 30 September 13
Major transitions: Prokaryote to Eukaryote
Prokaryotic cell
Cell membrane infoldings
Cell membrane
Cytoplasm
Nucleoid(containing DNA)
Endomembrane system
Endoplasmic reticulumNuclear membrane
Nucleus
Proteobacterium
Mitochondria
Cyanobacterium
Chloroplasts
Mitochondrion
†
†
†
1 A prokaryote grows in size and develops infoldings in its cell membrane to increase itssurface area to volume ratio.
2 The infoldings eventually pinch off from the cell membrane, forming an early endomembrane system. It encloses the nucleoid, making a membrane-bound nucleus.This is the first eukaryote.
3
5 Some eukaryotes go on to acquire additional endosymbionts—the cyanobacteria, a group of bacteria capable of photosynthesis. They become chloroplasts.
Ancestor of plants and algæ
Ancestor of animals, fungi, and other heterotrophs
First eukaryote
The aerobe's ability to use oxygen to make energy be-comes an asset for the host, allowing it to thrive in an in-creasingly oxygen-rich environ-ment as the other eukaryotes go extinct. The proteobacterium is eventually assimilated and becomes a mitochondrion.
Some eukaryotes go on to ac-quire additional endosymbionts — the cyanobacteria, a group of bacteria capable of photosynthe-sis. They become chloroplasts.Anaerobic (oxygen using) proteo-
bacterium enters the eukaryote, either as prey or a parasite, and manages to avoid digestion. It becomes an endosymbiont, or a cell living inside another cell.
Monday, 30 September 13
Major transitions: sex
•See lectures Week 5.
Monday, 30 September 13
Major transitions: multicellularity
Monday, 30 September 13
Major transitions: multicellularityGreen algae: Inspiration for what may have occurred: Volvocales
Monday, 30 September 13
Major transitions: multicellularityGreen algae: Inspiration for what may have occurred: Volvocales
Monday, 30 September 13
e.g.: artificial selection for multicellularity in S. cerevisiae yeast
Ratcliff et al 2012Monday, 30 September 13
Major transitions: multicellularityGreen algae: Inspiration for what may have occurred: Volvocales
Monday, 30 September 13
VolvoxSomatic cells
Gonidia
Monday, 30 September 13
Major transitions: eusociality
•Solitary lifestyle --> Eusociality1. Reproductive division of labor 2. Overlapping generations (older offspring help younger offspring)
3. Cooperative care of young
Eg: ants, bees, wasps, termites. But also: naked mole rats, a beetle, a shrimp...
Monday, 30 September 13
Hamilton, 1964
Major transitions: eusociality
•Kin selection: can favor the reproductive success of an organism's relatives (ie. indirect fitness), even at a cost to the organism's own survival and reproduction.
•Hamilton’s rule: genes for altruism increase in frequency when:
indirect fitness benefits to the receiver (B) ,
B
exceeds costs to the altruist (C).
> Cr ×
reduced by the coefficient of relatedness (r),
Monday, 30 September 13
© Alex Wild & othersMonday, 30 September 13
© National Geographic
Atta leaf-cutter ants
Monday, 30 September 13
© National Geographic
Atta leaf-cutter ants
Monday, 30 September 13
© National Geographic
Atta leaf-cutter ants
Monday, 30 September 13
Monday, 30 September 13
Oecophylla Weaver ants
© ameisenforum.de
Monday, 30 September 13
© ameisenforum.de
Fourmis tisserandes
Monday, 30 September 13
© ameisenforum.de
Oecophylla Weaver ants
Monday, 30 September 13
© forestryimages.org© wynnie@flickrMonday, 30 September 13
Tofilski et al 2008
Forelius pusillus
Monday, 30 September 13
Tofilski et al 2008
Forelius pusillus hides the nest entrance at night
Monday, 30 September 13
Tofilski et al 2008
Forelius pusillus hides the nest entrance at night
Monday, 30 September 13
Tofilski et al 2008
Forelius pusillus hides the nest entrance at night
Monday, 30 September 13
Tofilski et al 2008
Forelius pusillus hides the nest entrance at night
Monday, 30 September 13
Avant
Workers staying outside die« preventive self-sacrifice »
Tofilski et al 2008
Forelius pusillus hides the nest entrance at night
Monday, 30 September 13
Dorylus driver ants: ants with no home
© BBC
Monday, 30 September 13
Animal biomass (Brazilian rainforest)
from Fittkau & Klinge 1973
Other insects AmphibiansReptiles
Birds
Mammals
Earthworms
Spiders
Soil fauna excluding earthworms,
ants & termites
Ants & termites
Monday, 30 September 13
Today
1. Major transitions in evolution
2. Geological timescales
3. Major geological drivers of evolution
4. Recent major extinction events
Monday, 30 September 13
Monday, 30 September 13
your student id & tell her to add you to this module.
If QMPlus isn’t working
Monday, 30 September 13
“Complexity of life” didn’t increase linearly.
2. Geological time scalesDefined by changes in flora and fauna (seen in fossil record).
Eon > Era > Period > Epoch
Monday, 30 September 13
4550 Ma:
HominidsMammalsLand plantsAnimalsMulticellular lifeEukaryotesProkaryotes
Hadean
Arch
eanProterozoic
Paleozoic
Mesozoic
Cenozoic
4527 Ma:Formation of the Moon
4.6 Ga
4 Ga
3.8 Ga
3 Ga
2.5 Ga
2 Ga
1 Ga
542 M
a
251 Ma65 Ma ca. 4000 Ma: End of the
Late Heavy Bombardment;first life
ca. 3500 Ma:Photosynthesis starts
ca. 2300 Ma:Atmosphere becomes oxygen-rich;
750-635 Ma:Two Snowball Earths
ca. 530 Ma:Cambrian explosion
ca. 380 Ma:First vertebrate land animals
230-65 Ma:Dinosaurs
2 Ma:First Hominids
Ga = Billion years agoMa = Million years ago
Eon
Eon
Eon
EraEra
Era
Phaneroz
oic
Eon
Geological timescales: Eon > Era > Period > Epoch
Monday, 30 September 13
End of Proterozoic biota
Dickinsonia
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Trilobites
Cambrian to late permian
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50100150200250300350400450500 0542
0
1
2
3
4
5
Millions of Years Ago
Thou
sand
s of
Gen
era
Cm O S D C P T J K Pg N
Biodiversity during the PhanerozoicAll Genera
Well-Resolved Genera
Long-Term Trend
The “Big 5” Mass Extinctions
Other Extinction Events
Monday, 30 September 13
4550 Ma:
HominidsMammalsLand plantsAnimalsMulticellular lifeEukaryotesProkaryotes
Hadean
Arch
eanProterozoic
Paleozoic
Mesozoic
Cenozoic
4527 Ma:Formation of the Moon
4.6 Ga
4 Ga
3.8 Ga
3 Ga
2.5 Ga
2 Ga
1 Ga
542 M
a
251 Ma65 Ma ca. 4000 Ma: End of the
Late Heavy Bombardment;first life
ca. 3500 Ma:Photosynthesis starts
ca. 2300 Ma:Atmosphere becomes oxygen-rich;
750-635 Ma:Two Snowball Earths
ca. 530 Ma:Cambrian explosion
ca. 380 Ma:First vertebrate land animals
230-65 Ma:Dinosaurs
2 Ma:First Hominids
Ga = Billion years agoMa = Million years ago
Eon
Eon
Eon
EraEra
Era
Phaneroz
oic
Eon
Geological timescales: Eon > Era > Period > Epoch
Monday, 30 September 13
Earth
Life
Eukaryotes
Homo sapiens: 5 m
eters
Whitechapel: Dinosaurs extinct
NH
M: first tetrapod
Ham
mersm
ith: Cam
brian explosion
Monday, 30 September 13
Today
1. Major transitions in evolution
2. Geological timescales
3. Major geological drivers of evolution
4. Recent major extinction events
Monday, 30 September 13
3. Major geological drivers of evolution
•Tectonic movement (of continental plates)
•Vulcanism
•Climate change
•Meteorites
Conditions on earth change.
Monday, 30 September 13
Plate tectonics
12
354
Monday, 30 September 13
Crustal plates and continental drift
Monday, 30 September 13
Recent continental movements...
TETHYS SEA
LAURASIA
GONDWANA
EquatorTriassic 200 Mya
Pangaea - single supercontinent
Monday, 30 September 13
Fossil distribution
GondwanaMonday, 30 September 13
Earthquakes
•Some tectonic movement is violent.
•E.g. 2004 Sumatra earthquake & tsunami...
Monday, 30 September 13
Vulcanism•Local climate change (e.g. thermal vents, hot springs...)
•Global climate change: Emission of gasses & particles.
•New geological barriers (migration...)
•New islands (“Malay archipelago”, Galapagos... Hawaii... )
Deccan traps
Eyjafjallajokull
Monday, 30 September 13
Climate change
(since Cambrian)
Monday, 30 September 13
3. Major geological drivers of evolution
•Tectonic movement (of continental plates)
•Vulcanism
•Climate change
•Meteorites
Conditions on earth change.
Monday, 30 September 13
Vulcanism
Tectonic movement
Meteorite impact
Climate change?
?
Consequences: • Large scale migrations• Speciation• Mass extinctions• Adaptive radiations
3. Major geological drivers of evolution
Monday, 30 September 13
Today
1. Major transitions in evolution
2. Geological timescales
3. Major geological drivers of evolution
4. Recent major extinction events
Monday, 30 September 13
4. Recent major extinction events
Pg
fraction of genera present in each time interval but extinct in
the following interval
KT: K
-Pg
Cre
tace
ous–
Paleo
gene
Triass
ic-Ju
rass
icPerm
ian-
Triass
ic
Late
Dev
onia
n
Ord
ovic
ian–
Silu
rian
Today
Monday, 30 September 13
Monday, 30 September 13
•Oxygen levels.• Tetrapods and early amniotes.• Tropical conditions around equatorial landmasses.• Damp forests: tall trees & lush undergrowth: giant club mosses, lycopods, ferns & seed ferns.• Decaying undergrowth forms coal.• Good habitats for terrestrial invertebrates including spiders, millipedes and insects (e.g. giant dragonflies).
Pangaea - single supercontinent
Carboniferous/Permian
Monday, 30 September 13
Dimetrodon(sub-class Synapsida = “mammal-like reptiles”)
Early Permian mammal-like reptiles
Monday, 30 September 13
Climate change
(since Cambrian)
Monday, 30 September 13
Permian-Triassic Extinction
Sun et al Science 2012
Went extinct: •Up to 96% of marine species & 70% of terrestrial vertebrates•21 terrestrial tetrapod families (63%)• 7 orders of insects
Monday, 30 September 13
Monday, 30 September 13
Jurassic/Cretaceous
•Mammal-like reptiles were replaced as dominant land vertebrates by reptiles (dinosaurs).
• Lizards, modern amphibians and early birds appear.
• The conifer- and fern-dominated vegetation of the Late Triassic continued into the Jurassic.
Monday, 30 September 13
Cretaceous–Paleogene (KT) extinction66 million years ago
Subsequently, many adaptive radiations to fill newly vacant niches.eg. mammals, fish, many insects
AmmoniteMosasaur
(marine reptile) Non-bird dinosaurs
Most Plant-eating insects
75% of all species became extinct (50% of genera). Including:
Monday, 30 September 13
http://www.scotese.com/earth.htm)
Cretaceous–Paleogene (KT) extinction66 million years ago
Monday, 30 September 13
Evidence for Chixulub impact
Magnetic field near siteCrater : 180km diameter; bolide: 10km.
Monday, 30 September 13
•Bolide impact at Chixulub. •huge tsunamis•cloud of dust and water vapour, blocking sun.•plants & phytoplankton die (bottom of food chain) --> animals starve
•dramatic climate & temperature changes are difficult (easier for warm-blooded?)
•Additional causes? •Some groups were ALREADY in decline •Additional impacts?•Deccan traps (India) - 30,000 years of volcanic activity (lava/gas release)
Cretaceous–Paleogene (KT) extinction66 million years ago
Monday, 30 September 13
Monday, 30 September 13
Diprotodon, Australia, extinct 40,000 ya
Dodo, Mauritius, extinct since 1662
Ongoing Anthropocene extinction•Hunting•Habitat destruction, modification & fragmentation
Passenger PigeonNorth America; extinct since 1914.
Glyptodon, Americas, extinct ~12000 years ago
Monday, 30 September 13
Ongoing Anthropocene extinction•Hunting•Habitat destruction, modification & fragmentation•Pollution/Overexploitation•Spread of invasive species - & new pathogens•Climate change
Monday, 30 September 13
Rainforest loss in Sumatra
Margono et al 2012Monday, 30 September 13
Summary.
•The history of the earth is divided into geological time periods
• These are defined by characteristic flora and fauna
•Large-scale changes in biodiversity (mass extinctions) were triggered by continental movement and catastrophic events
Monday, 30 September 13
QMPlus Fail.
http://www.slideshare.net/yannickwurm/
http://qmplus.qmul.ac.uk/course/view.php?id=3972
Week 3: Fossils, DNA and Molecules
twitter : yannick__
Monday, 30 September 13