Evolution lectures 3 & 4 slideshare

Geological times & continental drift

Natural History Museum

QMUL Demonstrators

William Pritchard

MaïtéGuignard

SebastianBailey

PhilipSanders

© National Geographic

Atta leaf-cutter ants

Mini-summary of lectures 1 & 2

3 Schools of evolutionary thought

• Lamarck: characteristics acquired by an individual are passed on to offspring.

• Linneaus: each species was separately created.

3 Schools of evolutionary thought

• Lamarck: characteristics acquired by an individual are passed on to offspring.

• Linneaus: each species was separately created.

• Darwin & Wallace: viewed evolution as descent with modification.

1. The Fossil Record

2. Comparative Anatomy

3. Comparative Embryology

4. Vestigial Structures

5. Domestication (artificial selection)

Darwin’s evidence for evolution

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.

“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)




• Darwin’s Theory of Evolution by Natural Selection (1859)• Mendel’s Laws of Heredity (1866, 1900; see SBS 008)




• Darwin’s Theory of Evolution by Natural Selection (1859)• Mendel’s Laws of Heredity (1866, 1900; see SBS 008)• Cytogenetics (1902, 1904 - )




• 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)




• 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)

Today

1. Major transitions in evolution

2. Geological timescales

3. Major drivers of evolution

4. Examples of major events.

Major transitions: early life


•Early life:


•Early life:•Replicating molecules


•Early life:•Replicating molecules•Compartmentalization



•RNA world (RNA as information & enzymes) to DNA information & protein enzymes




•Linkage of replicators (chromosomes)




•Linkage of replicators (chromosomes)

•Prokaryote to Eukaryote

Major transitions: sex

•Lecture 14...

Major transitions: multicellularityGreen algae: Inspiration for what may have occurred: Volvocales

http://en.wikipedia.org/wiki/Volvocales

http://en.wikipedia.org/wiki/Volvocales

Major transitions: eusociality


•Solitary lifestyle --> Eusociality1. Reproductive division of labor 2. Overlapping generations (older offspring help younger offspring)3. Cooperative care of young


•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...

Major transitions: culture

•Lecture 13...

But “complexity of life” didn’t increase linearly.


2. Geological time scales


2. Geological time scalesDefined by changes in flora and fauna (seen in fossil record).


2. Geological time scalesDefined by changes in flora and fauna (seen in fossil record).

Eon > Era > Period > Epoch

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;

first Snowball Earth

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

Geological timescales: Eon > Era > Period > Epoch

End of Proterozoic (Ediacaran) biota

Dickinsonia

Trilobites

Cambrian to late permian

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;

first Snowball Earth

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

Geological timescales: Eon > Era > Period > Epoch

Earth

Life

Earth

Life

Eukaryotes

Earth

Life

EukaryotesN

HM

: first tetrapod

Earth

Life

Eukaryotes

Whitechapel: Dinosaurs extinct

NH

M: first tetrapod

Earth

Life

Eukaryotes

Homo sapiens: 5 m

eters

Whitechapel: Dinosaurs extinct

NH

M: first tetrapod


•Tectonic movement (of continental plates)

•Vulcanism

•Climate change

•Meteorites

Conditions on earth change.

Plate tectonics

Crustal plates and continental drift

Fossil distribution

Recent continental movements...

Earthquakes

•Some tectonic movement is violent.

•E.g. 2004 Sumatra earthquake & tsunami...

Vulcanism

Vulcanism•Local climate change (e.g. thermal vents, hot springs...)


•Global climate change: Emission of gasses & particles.

Eyjafjallajokull



•New geological barriers (migration...)

Deccan traps

Eyjafjallajokull



•New geological barriers (migration...)

•New islands (Indonesia... Hawaii... )

Deccan traps

Eyjafjallajokull

Climate change

Snowball earths?


•Tectonic movement (of continental plates)

•Vulcanism

•Climate change

•Meteorites

Conditions on earth change.


Vulcanism

Tectonic movement

Meteorite impact

Climate change?

?


Vulcanism

Tectonic movement

Meteorite impact

Climate change?

?

Consequences:


Vulcanism

Tectonic movement

Meteorite impact

Climate change?

?

Consequences: • Large scale migrations


Vulcanism

Tectonic movement

Meteorite impact

Climate change?

?

Consequences: • Large scale migrations• Speciation


Vulcanism

Tectonic movement

Meteorite impact

Climate change?

?

Consequences: • Large scale migrations• Speciation• Mass extinctions


Vulcanism

Tectonic movement

Meteorite impact

Climate change?

?

Consequences: • Large scale migrations• Speciation• Mass extinctions• Adaptive radiations

Module page

https://www2.sbcs.qmul.ac.uk/control-panel--> Modules --> Evolution

https://www2.sbcs.qmul.ac.uk/control-panel

https://www2.sbcs.qmul.ac.uk/control-panel

Today

1. Major transitions in evolution

2. Geological timescales


4. Examples of major events: two recent extinctions

4. Recent major exinction

Pg

K-Pg

(KT)

fraction of genera present in each time interval but extinct in the following interval

Tr-J

P-Tr

Late

DO-S

Today

Late Carboniferous 306 Mya


• Tetrapods and early amniotes.


• Tetrapods and early amniotes.• Tropical conditions around equatorial landmasses.


• Tetrapods and early amniotes.• Tropical conditions around equatorial landmasses.• Damp forests: tall trees & lush undergrowth: giant club mosses, lycopods, ferns & seed ferns.


• 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.


• 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).

DimetrodonOrder Pelycosauria (sub-class Synapsida)

Early Permian mammal-like reptiles

Permian-Triassic Extinction

Sun et al Science 2012

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

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.

Cretaceous–Paleogene (KT) extinction66 million years ago

75% of all species became extinct (50% of genera). Including:


Ammonite



AmmoniteMosasaur

(marine reptile)



AmmoniteMosasaur

(marine reptile) Non-bird dinosaurs



AmmoniteMosasaur


Most Plant-eating insects



Subsequently, many adaptive radiations to fill newly vacant niches.eg. mammals, fish, many insects

AmmoniteMosasaur


Most Plant-eating insects


http://www.scotese.com/earth.htm)


Evidence for Chixulub impact

Evidence for Chixulub impact

Magnetic field near siteCrater : 180km diameter; bolide: 10km.

•Bolide impact at Chixulub.


•Bolide impact at Chixulub. •huge tsunamis


•Bolide impact at Chixulub. •huge tsunamis•cloud of dust and water vapour, blocking sun.


•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?




•Additional causes? •Some groups were ALREADY in decline




•Additional causes? •Some groups were ALREADY in decline •Additional impacts?




•Additional causes? •Some groups were ALREADY in decline •Additional impacts?•Deccan traps (India) - 30,000 years of volcanic activity (lava/gas release)


Ongoing Anthropocene extinction?

•Hunting•Habitat destruction, modification & fragmentation•Pollution •Climate change•Spread of invasive species•Overexploitation

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 were triggered by continental movement and catastrophic events (mass extinctions)

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William Pritchard

MaïtéGuignard

SebastianBailey

PhilipSanders

Evolution lectures 3 & 4 slideshare

Education

Transcript of Evolution lectures 3 & 4 slideshare