6 . from meso- to cenozoic
DESCRIPTION
6 . From Meso- to Cenozoic. Triassic 250-205 Pangaea. Jurassic 205-140 Laurasia and Gondwana. Cretaceous 140-65 Formation of present day continents. Hot and dry Polar regions moist and temperate . Warm and dry No ice caps at poles. - PowerPoint PPT PresentationTRANSCRIPT
6. From Meso- to Cenozoic
Triassic 250-205Pangaea
Jurassic 205-140Laurasia and Gondwana
Cretaceous 140-65Formation of present day continents
Hot and dryPolar regions moist
and temperate
Warm and dryNo ice caps at poles
Very warm no ice caps at poles. Ocean temperatures
about 15-20º higher than today
Pangaea
Cretaceous 140-65Formation of present days continents
Very warm no ice caps at poles. Ocean temperatures about 15-20º higher than today
From Müller et al. 2008)
Saurischia
Ornithischia
Stegosauria
Ceratopsia
Pterosauria
Sauropoda
Therapoda
ArchaeopteryxMicroraptor gui
Aves
Archosauromorpha
Triceratops
Stegosaurus
Diplodocus
Dinosauria
Herbivores
Herbivores
Mainly Carnivores
Triassic 250-205Pangaea
Jurassic 205-140Laurasia and Gondwana
Cretaceous 140-65Formation of present days continents
Iguanodon
Oviraptor
Carnivores
(Flight / display feathers)Paraves
Nemicolopterus crypticus
Thyranosaurus rex(Down feathers)
0
100
200
300
400
500
600
Late Triassic EarlyJurassic
MiddleJurrasic
Late Jurrasic EarlyCretaceous
LateCretaceous
Maastrichtian Total
Epoch
Num
ber o
f kno
wn
gene
ra
zMesozoic dinosaur diversity
0
100
200
300
400
500
600
700
Late Triassic EarlyJurassic
MiddleJurrasic
Late Jurrasic EarlyCretaceous
LateCretaceous
Maastrichtian Total
Epoch
Num
ber o
f gen
era
z
Estimated diversity
Data from Wang, Dodson (2006), Sullivan (2006)
Total 1844 genera
RecentBirds: 1200 generaMammals: 1135 genera
ACE
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
Percent species observed
Per
cent
spe
cies
est
imat
ed
z
Jurassic 205-140Laurasia and Gondwana
Cretaceous 140-65Formation of present days continents
Basal Theropoda
Archaeopteryx
Confuciusornis
Yixianornis
Jinfengopteryx
Rahonavisprobably flight
Troodon(large brain, stereoscopic sight, nocturnal
Mahakala
Deinonychus
Velociraptor
Aves
ParavesFlight / display
feathershomoiotherm,
Pneumatic bones
10 – 80 kg
< 1 – 50 kg
1 – 5 kg
< 1 kg<1 – 60 kg
<1 – 20 kg
< 1 kg
Downfeathers
Dromaeosauridae
Avialae
Cretaceous 140-65 Paleogene 65-23 Neogene 23-
Evolution of birds
Palaeognathae
Neognathae
Anseriformes
Galliformes
Passeriformes
Psittaciformes
Apodiformes
Falconiformes
Others
Tinamiformes
Struthioniformes
Strigiformes
Adaptive radiation
Triassic250-205
Jurassic205-140
Cretaceous140-65
Cycadophyta
Gingkophyta
Permian290-250
Pinophyta
Carboni-ferous
355-290
Cordaitales GnetophytaWelwitschia mirabilis
Magnoliophyta
Archaefructus liaoningensis
Gingko
Nymphaeaceae„Dicotyls”„Monocotyls”
Amborella trichopoda
Adaptive radiation
Adaptive radiation
Cretaceous 140-65Cenozoic 65-
Paleogene 65-23 Neogene 23-Mesozoic 250-65
Monotremata
Marsupialia
Afrotheria Elephants
Elephant shrews
Xenarthra Ant eaters
EuarchontogliresPrimates
Tree shrews
RodentiaLagomorpha
LaurasiatheriaChiroptera
Cetarthiodactyla
Perissodactyla
Carnivora
Adaptive radiation
Genetic diversification
Extant mammalian lineages
Adaptive radiation
Adaptive radiation
Adaptive radiation
Cetacea
Devonian TriassianPermianCarboniferous CretaceousJurassic Tertiary to recent
PalaeodictyopteraOdonata
EphemeropteraDictyopteraPlecopteraZorapteraEmbiopteraIsoptera
GrylloblatodeaDermaptera
PhasmidaOrthopteraMallophagaPsocopteraThysanopteraHeteropteraHymenopteraNeuropteraColeoptera
MecopteraSiphonaptera
Diptera
LepidopteraTrichoptera
Genetic diversification
Genetic diversification
In the Triassic period all extant taxa already existed
The rise of insects
Adaptive radiation
HymenopteraNeuropteraColeoptera
MecopteraSiphonaptera
Diptera
LepidopteraTrichoptera
The rise of holometabolous insects
Jurassic
Cretaceous
0
100
200
300
400
500
600
700
-600 -500 -400 -300 -200 -100 0
Num
ber o
f fam
ilies
K O S D C P T J Kr Pa NE
InsectsVascular plants
Terrestrial Tetrapoda
Num
ber o
f gen
era
Cretaceous 140-65
Photos from: http://www.fossilmuseum.net/Fossil_Galleries/Insect_Galleries_by_Order/
Paleogene 65-23
The earliest ants
An early bee
A swarm of midgesThe earliest moth
An early lacewing An early weevil A weevil in amber
The Cretaceous –Tertiary impactK-T boundary
The K-T boundary. The arrow indicates a layer of Iridium rich ash.
Iridium is rare on the surface of the earth but much more common in Chondrite meteors
Luis Alvarez 1911-
Walter Alvarez 1940-
The Chicxulub Impact structure buried beneath the Yucatan Peninsula has 150 -
300 km in diameter
Age dates of melt rock in the structure have at date of 65 Ma.
The K-T layer is divided into two parts, the Magic Layer (3 mm thick) and the Ejecta Layer (2 cm thick). They contain
• Siderophiles contain the rare Earth Elements Os, Au, Pt, Ni, Co, Pd, and Ir. Iridium (Ir) has been found in the K-T layer around the world (New Zealand, Denmark, and Italy). The layer is about 100,000-years-thick.
• Tektites are abundant in the K-T layer.They are quartz grains which are vaporized under intense heat and pressure, and cool into glass beads with no crystalline structure. Tektites were probably formed during a meteorite or comet collision.
• Shocked quartz - When quartz is put under extremely high pressure, it can cleave in parallel planes. Shocked quartz is found at nuclear bomb sites and known meteorite impact areas. Shocked quartz is abundant in the K-T layer.
• Stishovite (Silicon Dioxide) - a form of quartz created under conditions of high heat and pressure. It is used as an indicator of meteor impact. It has been found in abnormally high abundance in the K-T layer.
• Glass beads - Kenneth Miller has discovered a two-inch layer of glass beads in the K-T layer near the Bass River in New Jersey, USA, supporting Alvarez' theory.
Extinctions at the K-T boundary were not evenly distributed across taxa
15% of all marine families went extinct, 50 % at generic level, maybe 80-90 % of all species.
Affected were mainly plankton, marine predators, and shallow water communities.
25 % of terrestrial families and 56 % at generic level went extinct.
Nothing bigger than 25 kg survived (predators and herbivores).
Unaffected were higher plants (10% extinction), mammals (rise of 20%), and birds.
However, dinosaur diversity declined even before the impact.
Probably the impact wiped out the last survivors.
Cretaceous and Paleogene sawan enormous diversification of
• Angiospermes• Holometabolic insects (Coleoptera, Hymenoptera,
Lepidoptera, Diptera)• Mammals
• Birds• Gastropods
a decline in diversity of• Gymnospermes
• Brachiopods
the extinction of • Ammonites• Belemnites• Dinosaurs
0
20
40
60
80
100
120
607080
Time (mya)
Num
ber o
f tax
a
zSpecies
Genera
K-T boundary
Global species richness of dinosaurs
Data from Sullivan (2006)
Today’s reading
The Mesozoic era: http://www.palaeos.com/Mesozoic/Mesozoic.htm http://www.palaeos.com/Mesozoic/Mesozoic2.htmlThe Cenozoic era: http://www.palaeos.com/Cenozoic/Neogene.html
http://www.palaeos.com/Cenozoic/Paleogene.html