iv. early life
DESCRIPTION
IV. Early Life - the first cells were probably heterotrophs that simply absorbed nutrients and ATP from the environment. - as these substances became rare, there was strong selection for cells that could manufacture their own energy storage molecules. - PowerPoint PPT PresentationTRANSCRIPT
History of Life
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
5 by
a: O
ldes
t F
ossi
ls
IV. Early Life
- the first cells were probably heterotrophs that simply absorbed nutrients and ATP from the environment.
- as these substances became rare, there was strong selection for cells that could manufacture their own energy storage molecules.
- the most primitive cells are methanogens, but these are NOT the oldest fossils.
IV. Early Life
- the second type of cells were probably like green-sulphur bacteria, which used H2S as an electron donor, in the presence of sunlight, to photosynthesize.
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
5 by
a: O
ldes
t F
ossi
ls
Stromatolites - communities of layered 'bacteria'
IV. Early Life
- the evolution of oxygenic photosynthesis was MAJOR. It allowed life to exploit more habitats, and it produced a powerful oxidating agent! These stromatolites, which date to > 3 bya are microbial communities.
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
4 by
a: O
ldes
t F
ossi
ls
2.3-
2.0
bya:
Oxy
gen
in
Atm
osph
ere
IV. Early Life
- about 2.3-1.8 bya, the concentration of oxygen began to increase in the ocean and oxidize eroded materials minerals... deposited as 'banded iron formations'.
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
4 by
a: O
ldes
t F
ossi
ls
2.3-
2.0
bya:
Oxy
gen
1.8
bya:
firs
t eu
kary
ote
IV. Early Life
- 2.0-1.7 bya - evolution of eukaryotes.... endosymbiosis.
IV. Early Life
Eukaryote Characteristics
- membrane bound nucleus
- organelles
- sexual reproduction
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
4 by
a: O
ldes
t F
ossi
ls
2.3-
2.0
bya:
Oxy
gen
1.8
bya:
firs
t eu
kary
ote
0.9
bya:
firs
t an
imal
s
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
4 by
a: O
ldes
t F
ossi
ls
2.3-
2.0
bya:
Oxy
gen
1.8
bya:
firs
t eu
kary
ote
0.9
bya:
firs
t an
imal
s
0.5
bya:
Cam
bria
n
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
4 by
a: O
ldes
t F
ossi
ls
2.3-
2.0
bya:
Oxy
gen
1.8
bya:
firs
t eu
kary
ote
0.9
bya:
firs
t an
imal
s
0.5
bya:
Cam
bria
n0.
24 b
ya:M
esoz
oic
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
4 by
a: O
ldes
t F
ossi
ls
2.3-
2.0
bya:
Oxy
gen
1.8
bya:
firs
t eu
kary
ote
0.9
bya:
firs
t an
imal
s
0.5
bya:
Cam
bria
n0.
24 b
ya:M
esoz
oic
0.06
5 by
a:C
enoz
oic
I. Earth History
4.5
bya:
Ear
th F
orm
s
4.0
bya:
Old
est
Roc
ks3.
4 by
a: O
ldes
t F
ossi
ls
2.3-
2.0
bya:
Oxy
gen
1.8
bya:
firs
t eu
kary
ote
0.9
bya:
firs
t an
imal
s
0.5
bya:
Cam
bria
n0.
24 b
ya:M
esoz
oic
0.06
5 by
a:C
enoz
oic
4.5 million to present
(1/1000th of earth history)
I. The "Precambrian"
I. The "Precambrian"
Vendian - 610 mya - 544 mya.
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Dicksonia - thought to be a segmented worm
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Eoporpita - Cnidarian polyp
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Cyclomedusa - Cnidarian polyp; up to 1 meter in diameter
I. The "Precambrian"
- The Ediacaran(610-544)
The first fossil animals
Charnia - sea pen (related to Cnidarians) - up to 1 m long
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Nemiana - may be a cnidarian or algal colony...
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Pteridinium - cnidarian???
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Arkarua - Echinoderm?
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Spriggina - soft-bodied, but assignment to Annelida is doubtful... some describe it as a soft-bodied arthropod...(it is similar to trilobites...)
Spriggina
trilobite
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Tribrachidium - soft-bodied, but enigmatic... maybe a cnidarian or an echinoderm..???
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Kimberella - recent analysis suggest it might be an early mollusc.. a bit chiton-like...
I. The "Precambrian"
- The Ediacaran (610-544)
The first fossil animals
Largely a radiation of soft-bodied forms.
In addition, however, the first predatory animals (Cnidarians...)
So, although rare, there is a radiation of soft-bodied organisms before the Cambrian... and representatives from several major phyla (or sister phyla) appear.
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
- representatives of nearly all modern phyla (no Bryozoans)
- representatives of extinct phyla
- radiation of animals with hard parts
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Thaumaptilon
Sea Pen - Cnidaria
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Sydneyia - Arthropod
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Canadia - Annelida
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Choia - Porifera
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Aysheaia - Onychophora
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Ottoia - Priapulida
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Canadapsis - Arthropoda (Crustacea)
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Waptia - Arthropoda (Crustacea)
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Leanchoilia - Arthropoda (Crustacea)
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Pikaia - Chordata
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of extant phyla:
Hallucigenia - Onychophora
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of EXTINCT phyla or subphyla:
Olenoides – Trilobita (Arthropoda)
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of EXTINCT phyla or subphyla:
Marella - primitive Arthropod
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of EXTINCT phyla or subphyla:
Haplophrentis - Hyolithid
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of organisms unassigned to any major group:
Opabinia
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of organisms unassigned to any major group:
Amiskwia
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of organisms unassigned to any major group:
Anomalocaris
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- an 'explosion' of fossil animals:
examples of organisms unassigned to any major group:
Wiwaxia
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
Burgess Shale Community
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
WHY?
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
WHY?
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Sampling Error? Since hard-parts fossilize better than soft parts, is the 'Explosion' just a reflection of the greater likelyhood of fossilization?
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Sampling Error? Since hard-parts fossilize better than soft parts, is the 'Explosion' just a reflection of the greater likelihood of fossilization?
Predation? The Vendian radiation contained lots of predators..Cnidarians. Hard parts would be adaptive protection against these predators, as well as the predators in the Cambrian.
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Sampling Error? Since hard-parts fossilize better than soft parts, is the 'Explosion' just a reflection of the greater likelihood of fossilization?
Predation? The Vendian radiation contained lots of predators..Cnidarians. Hard parts would be adaptive protection against these predators, as well as the predators in the Cambrian.
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Sampling Error? Since hard-parts fossilize better than soft parts, is the 'Explosion' just a reflection of the greater likelihood of fossilization?
Predation? The Vendian radiation contained lots of predators..Cnidarians. Hard parts would be adaptive protection against these predators, as well as the predators in the Cambrian.
Also, it's important to realize that this "Explosion" occurred over 10 my.... not 'instantaneous'...
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Our first example of innovation, radiation, and competitive contraction
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Our first example of innovation, radiation, and competitive contraction
Hard parts
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Our first example of innovation, radiation, and competitive contraction
II. The Paleozoic Era
A. The Cambrian Period (544 - 510 mya)
- First major radiation of hard-bodied org's
Our first example of innovation, radiation, and competitive contraction
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian
- The Cambrian 'Explosion'
- The Cambrian Fauna and Beyond
- The Cambrian Fauna and Beyond
The fauna was dominated by trilobites...
and the number of trilobite families peaked in the late Cambrian and declined through the Paleozoic. This marine fauna is known as the 'Cambrian Fauna' and represents the first great marine faunal assemblage in the fossil record.
- The Cambrian Fauna and Beyond
This fauna was replaced by the 'Paleozoic' ( or Brachiopod) fauna, and then by the Modern (or 'Gastropod-Mollusc') fauna in the Mesozoic.
- The Cambrian Fauna and Beyond
- What contributes to these patterns in diversity?
- The Cambrian Fauna and Beyond
- What contributes to these patterns in diversity?
Some paleontologists suggest a correlation between large scale diversity patterns and plate tectonics.
- The Cambrian Fauna and Beyond
- What contributes to these patterns in diversity?
Some paleontologists suggest a correlation between large scale diversity patterns and plate tectonics.
This is the supercontinent "Rodinia". It formed about 1 billion years ago, and began to break up in the Cambrian (544-510) and Ordovician (510-439).
- The Cambrian Fauna and Beyond
- What contributes to these patterns in diversity?
So, we have 'vicariance' at a large geologic scale, increase the abundance of shallow coastal habitats and the possibility of allopatric speciation, divergence, and radiations.
A similar radiation in diversity occurs in the Mesozoic when Pagaea breaks up... creating more shallow coastal areas...
- The Cambrian Fauna and Beyond
- What contributes to these patterns in diversity?
1) Vicariance
2) Nutrient Loading
- The Cambrian Fauna and Beyond
- What contributes to these patterns in diversity?
1) Vicariance
2) Nutrient Loadingincrease in shallow seas increases marine productivity and might increase food chain lengths and diversity.
also, evolution of more productive terrestrial biotas would increase nutrient contributions from runoff.
- The Cambrian Fauna and Beyond
- What contributes to these patterns in diversity?
1) Vicariance
2) Nutrient Loading
3) Mass Extinctions
Ice Age
Impact, C
limate
Vulcanism
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
- evolution of chordates
Cephalochordata
Craniata
Euchordata Hagfish (skull but no vertebrae...)
Vertebrata
Pikaia
Myllokunmingia 530 mya
Haikouichthys 530 mya
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
- evolution of chordates
Myllokunmingia 530 mya
Nature 1999
Myllokunmingia 530 mya
Haikouichthys ercaicunensis
early Cambrian
perhaps more advanced than Myllokunmingia,
but both may have had cartilaginous vertebrae... the first true verts!
Nature 2003
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
- inverts
new trilobites
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
- inverts
new trilobites
Nautiloid radiation
During the middle Ordovician some long-shelled forms like Endoceras and Cameroceras attained lengths of 4 to as much as 10 meters - among the largest molluscan shells ever
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
Radiation of Ostracoderms SILURIAN
"Ostracoderms"
Heterostracans
Astraspids
Arandaspids
Lampreys**
Osteostracans
JAWED FISHES**Tree of Life phylogeny; differs from Cowens.
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
Astraspis
Arandaspida
"Ostracoderms"
Bony plates; no paired fins; gill arches
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-510 mya)
B. Ordovician (510-439 mya)
- plants
the first terrestrial plant fossils are fragmentary; they are spores and cuticles (which signify land plants). In all likelihood they are 'hepatophyte' liverwort-like non-tracheophytes...
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-490 mya)
B. Ordovician (490-443 mya)
C. Silurian (443-417 mya)
- inverts
Brachipods begin to dominate; 80% of all individuals
C. Silurian (443-417 mya)
- inverts
Brachipods begin to dominate; 80% of all individuals
Reef-building corals
radiate
C. Silurian (443-417 mya)
- inverts
Brachipods begin to dominate; 80% of all individuals
Reef-building corals radiate
Crinoid echinoderms radiate
C. Silurian (443-417 mya)
- inverts
Brachipods begin to dominate; 80% of all individuals
Reef-building corals radiate
Crinoid echinoderms radiate
Eurypterids (sea scorpions) dominate (7 feet long)
C. Silurian (443-417 mya)
- inverts
Brachipods begin to dominate; 80% of all individuals
Reef-building corals radiate
Crinoid echinoderms radiate
Eurypterids (sea scorpions) dominate; Horseshoe crabs
Semi-aquatic scorpions and terrestrial Chelicerata evolve
Millipedes first completely terrestrial animals
C. Silurian (443-417 mya)
- inverts
- plants
C. Silurian (443-417 mya)
- inverts
- plants
radiation of the first vascular plants
4 species of Cooksonia, including those representing the Rhyniophytes and Lycophytes
C. Silurian (443-417 mya)
- inverts
- plants
- verts
C. Silurian (443-417 mya) - inverts - plants - verts
Radiation of Ostracoderms SILURIAN
"Ostracoderms"
Heterostracans
Astraspids
Arandaspids
Lampreys**
Osteostracans
JAWED FISHES**Tree of Life phylogeny; differs from Cowens.
C. Silurian (443-417 mya)
- inverts
- plants
- verts
- Heterostracans - over 300 species; very abundant
C. Silurian (443-417 mya)
- inverts
- plants
- verts
- Osteostracans
bottom-feeders, but with an important evolutionary advancement - paired fins
C. Silurian (443-417 mya)
- inverts
- plants
- verts
- Jawed Fishes (Gnathostomes)
- Acanthodians
C. Silurian (443-417 mya)
- inverts
- plants
- verts
- Jawed Fishes (Gnathostomes)
the oldest jawed fish fossils are Acanthodians... however, they are a group of bony fishes and it is likely that they were preceded by the cartilaginous Placoderms (which radiate in the Devonian)
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-490 mya)
B. Ordovician (490-443 mya)
C. Silurian (443-417 mya)
D. Devonian (417-354 mya)
- "The Age of Fishes"
D. Devonian (417-354 mya)
- inverts
crazy trilobite 50cm long.... Terataspis grandis
D. Devonian (417-354 mya)
- inverts:
- Ammonites
D. Devonian (417-354 mya)
- inverts:
- Ammonites
- Terrestrial Arthropods
- oldest spider - Attercopus
- mites
- trigonotarbids (no silk)
D. Devonian (417-354 mya)
- inverts:
- plants
Lycopod forests, then
Progymnosperm forests dominated by one genus, Archaeopteris 20m
D. Devonian (417-354 mya)
- inverts:
- plants
- verts:
- last of the ostracoderms...
Psammolepis over 2m
D. Devonian (417-354 mya)
- inverts:
- plants
- verts:
- last of the ostracoderms...
- the major radiation of jawed fish groups
Lobe-finned Fishes
Ray-finned Fishes
Bony Fish
Acanthodians
Teleosts
Chondrichthyes (Sharks, rays)
PlacodermsArthrodires
Antiarchs
D. Devonian (417-354 mya)
Fishes of the Middle Devonian locality of Lethen Bar, in Scotland (Givetian, about 377 Ma). They include antiarchs (1 Pterichthyodes); and arthrodire (2. Coccosteus) placoderms, acanthodians (3. Diplacanthus), ray-finned fish (4, Cheirolepis), lungfish (5, Dipterus), and osteolepiform lobe-finned fish (6. Osteolepis), representing the lineage that gave rise to land animals.
D. Devonian (417-354 mya)
- Placoderms
- Sharks
- Lobe-finned Fishes
- Ray-finned Fishes
- Tetrapods (from lobe-finned fishes)
D. Devonian (417-354 mya)
- Placoderms
- very abundant
- head shields
- shearing or crushing tooth plates
Dunkleosteus - 6m Arthrodire
Antiarch
D. Devonian (417-354 mya)
- Placoderms
- Sharks
Stethacanthus - 2m
D. Devonian (417-354 mya)
- Placoderms
- Sharks
D. Devonian (417-354 mya)
- Placoderms
- Sharks
- Ray-finned Fishes
D. Devonian (417-354 mya)
- Placoderms
- Sharks
- Ray-finned Fishes
D. Devonian (417-354 mya)
- Placoderms
- Sharks
- Ray-finned Fishes
- Lobe-finned Fishes
D. Devonian (417-354 mya)
- Placoderms
- Sharks
- Lobe-finned Fishes
385 mya
365 mya
Eusthenopteron
Panderichthys rhombolepis
Tiktaalik roseae
Acanthostega gunnari
Ichthyostega sp.
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-490 mya)
B. Ordovician (490-443 mya)
C. Silurian (443-417 mya)
D. Devonian (417-354 mya)
E. Carboniferous (359-300 mya)
E. Carboniferous (359-300 mya)
- inverts
Arthropleura -largest terrestrial arthropod - 2m
E. Carboniferous (359-300 mya)
- inverts
- radiation of insects
- evolution of flight
Meganeura monyi - largest insect ever
wingspan of 70 cm
E. Carboniferous (359-300 mya)
- inverts
- plants
The early Carboniferous saw a reduction in the Devonian forests and a dominance of small plants - lycopods and their kin.
Lepidodendron
Psaronius - fern
Lebachia - progymnosperm
Cordaites - progymnosperm
E. Carboniferous (359-300 mya)
- inverts
- plants
The early Carboniferous saw a reduction in the Devonian forests and a dominance of small plants - lycopods and their kin.
As the period proceeds, the giant lycopsid swamp forests evolve across the tropical continent of Euramerica.
There was lots of photosynthesis, but this was not balanced by decomposition (because much of the biomass was preserved in sediment, not broken down by decay). So, oxygen production by photosynthesis exceeded oxygen consumption by decomposition... and oxygen levels were probably very high...this may have allowed the enormous size of invertebrates.
E. Carboniferous (359-300 mya)
- inverts
- plants
E. Carboniferous (359-300 mya)
- inverts
- plants Coal deposits in shallow tropical swamps
E. Carboniferous (359-300 mya)
- inverts
- plants
- vertebrates
sharks replace placoderms as dominant in oceans;
The golden age of sharks - 45 Families
(currently 21)
E. Carboniferous (359-300 mya)
- inverts
- plants
- vertebrates
sharks replace placoderms as dominant in oceans;
ray finned fishes dominate in fresh water
- vertebrates
radiation of stem tetrapods!!
- vertebrates
radiation of stem tetrapods!!
- vertebrates
radiation of stem tetrapods!!
"Anthracosaurs"
E. Carboniferous (359-300 mya)
- inverts
- plants
- vertebrates
sharks replace placoderms as dominant in oceans;
ray finned fishes dominate in fresh water
stem tetrapods radiate!
"crown" tetrapods
Seymouriamorpha
Temnospondyls
Ichthyostegans
E. Carboniferous (359-300 mya)
- inverts
- plants
- vertebrates
stem tetrapods
Temnospondyls
a very diverse radiation of tetrapods, from alligator-like salamanders to large, scaled, frog-like creatures. Cowens places these ancestral to Amphibia only, but recent analyses put them as a sister clade to all crown tetrapods.
Temnospondyls
a very diverse radiation of tetrapods, from alligator-like salamanders to large, scaled, frog-like creatures. Cowens places these ancestral to Amphibia only, but recent analyses put them as a sister clade to all crown tetrapods.
Seymouriamorpha
Radiate in Permian
but earliest fossils from the Carboniferous... larvae have external gills, which pulls them out of the amniota...
- vertebrates
radiation of stem tetrapods!!
The Amniote Divide
The amniotic egg was a big advance
- amnion protects the embryo - yolk sac provides nourishment - allantoic sac holds waste produced by embryo
Resist desiccation
Provision embryo
allows for colonization of dry habitats
Primitive Amniotes
Hylonomus lyelli – an early reptile
Carboniferous of Nova Scotia
E. Carboniferous
- The Amniote Radiations
Anapsid ancestor
Hylonomus
Casineria
ANAPSID (turtles?)
DIAPSID
SYNAPSID
I. The Precambrian
- Vendian
II. Paleozoic
A. Cambrian (544-490 mya)
B. Ordovician (490-443 mya)
C. Silurian (443-417 mya)
D. Devonian (417-354 mya)
E. Carboniferous (359-300 mya)
F. Permian (300-251 mya)
F. Permian (300-251 mya)
Pangaea forms
The fusion of land masses reduced the amount of humid coastline and increased the extent of dry inland areas. This favored the amniote radiations over "amphibian" clades.
F. Permian
- The Amniote Radiations Diversify
Anapsid ancestor
Hylonomus
ANAPSID (turtles)
DIAPSID
SYNAPSID
F. Permian (300-251 mya)
Synapsids dominate through the early Permian
Mammals
Cynodonts
Gorgonopsids
Therapsids
Pelycosaurs
Dicynodonts
F. Permian (300-251 mya)
Pelycosaurs dominate early
include the great sail-finned animals like Dimetrodon
F. Permian (300-251 mya)
Early Therapsids, like Gorgonopsids, dominate in the mid-late Permian
Dinocephalians
Moschops
F. Permian (300-251 mya)
Dicynodonts come to numerical dominance in the late Permian
abundant herbivores
F. Permian (300-251 mya)
and the first Cynodonts appear
F. Permian (300-251 mya)
large herbivorous anapsids were also present
F. Permian (300-251 mya)
Diapsids were small and lizard-like; the Synapsids ruled terrestrial communities
F. Permian (300-251 mya)
- Plants!!
F. Permian (300-251 mya)
- Plants!!
- the dry climate reduced the great Carboniferous swamp forests; lycopods shrink...
- Ferns, and gymnosperms ("seed ferns", Ginkos, Cycads, and Conifers) gain prominence...
- In particular Glossopteris - a seed fern - that produces seeds on its leaves like sori of ferns...
The evolution of gymnosperms introduced two important adaptive features:
- pollen (male gametophyte) - no more swimming sperm; reduced reliance on open water habitats
- seed - protective seed coat reduced desiccation of embryo, and nutritious endosperm provisioned the embryo with energy. (Like the amniote egg).
F. Permian (300-251 mya)
The great Permian extinction!!!!
A huge mantle plume rises towards the surface...
F. Permian (300-251 mya)
The great Permian extinction!!!!
then it pops like a zit!!
F. Permian (300-251 mya)
The great Permian extinction!!!!
A huge mantle plume rises towards the surface...
resulting in a great bubble of flowing lava... the Siberian flats (200,000 squ. mi)
F. Permian (300-251 mya)
F. Permian (300-251 mya)
- results:
90-95% of marine species go extinct...
trilobites
placoderms
acanthodians
F. Permian (300-251 mya)
- results:
90-95% of marine species go extinct...
trilobites
placoderms
acanthodians
70% of all land families
pelycosaurs