Title: Stromatolites
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11Stromatolites
12Burgess Shale, Calgary
13Burgess Shale Fauna
14In the previous image, trilobites (1) live among
many species that are not normally preserved. A
typical Cambrian outcrop might produce only
trilobites, brachiopods (2), mollusks (3), and
crinoids (4). That is a tiny fraction of the full
Cambrian biota, better represented by the roster
of the Burgess Shale Cambrian Konservat-Lagerstatt
en. That community includes sponges Vauxia (5),
Hazelia (6), and Eifellia (7) brachipods Nisusia
(2) priapulid worms Ottoia (8) trilobites
Olenoides (1) other arthropods such as Sidneyia
(9), Leanchoilia (10), Marella (11), Canadaspis
(12), Helmetia (13), Burgessia (14), Tegopelte
(15), Naraoia (16), Waptia (17), Sanctacaris
(18), and Odaraia (19) lobopods Hallucigenia
(20) and Aysheaia (21) mollusks Scenella (3)
echinoderms Echmatocrinus (4) and chordates
Pikaia (22) among other oddities, including
Haplophrentis (23), Opabinia (24), Dinomischus
(25), Wiwaxia (26), Amiskwia (27), and
Anomalocaris (28). Â
15Burgess Shale Opabinia
Burgess Shale Marella
16Burgess Shale Hallucigenia
17Trilobites became a dominant Paleozoic life form.
Most did not.
18Burgess Shale Pikaia (oldest known chordate)
19The first fishes evolved from worm-like
chordates. Early fishes were jawless.
20Agnatha jawless fish
21The first fishes evolved from worm-like
chordates. Early fishes were jawless. Q? Are
there any left today?
22Yes. The lamprey.
23Evolution of fishes. The path to tetrapods goes
through fishes.
24Acanthodians
25Dunkleosteus
26Sharks and rays cartilaginous fishes, basically
unchanged for 400 million years
27Marine life in the Silurian continued much like
the Ordovician, with abundant corals, bivalves
(clam-like animals), trilobites, and
nautilus-like predators, but
28The Silurian period saw the evolution of the
first jawed fishes.
29Most bony fishes are ray-finned fishes.
30. only a few are lobe-finned fishes.
The Coelacanth Latimeria
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33Devonian life in the shallow inland seas
continued much as it had in the Silurian, with
extensive coral reefs and ocean plants.
34The major change in life in the Devonian occurred
on land, which had been devoid of life up until
then.Â
35The head and poison claw of a centipede. The
fossil compound eye of an insect. Fossil
remains of a millipede.
The first land animals are also found in the
Devonian period.
36Mississippian marine life was marked by extensive
shallow reef communities, including flora such as
crinoids.
37With much more land surface exposed in
Pennsylvanian time (as compared to Mississippian
time) extensive tropical forests were formed.
These would eventually be fossilized into
extensive coal deposits.
38The first amphibians evolved from lobe-finned
fishes in the Devonian period.
39Tiktaalik the 375-million-year-old missing
link between fish and amphibians, found in 2006.
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41PALEOZOIC AMPHIBIANSLeft and Above.
Ichthyostega. Preserved fossil and reconstructed
skeleton (Devonian).  Right. Cacops
reconstructed skeleton (Permian).
42First reptiles evolved in the Permian period from
amphibians.
43Recap.
44The reptiles, Thecodonts, gave rise to
crocodiles, pterosaurs, and dinosaurs.
45Massive extinction at the end of the Permian
marked the start of the dinosaurs.
(genus taxonomic group containing one or more
species)
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48- Possible causes of the massive Permian
extinction - Volcanism (Siberian traps)
- Impact (stishovite, shocked quartz, iridium and
other meteoritic materials) - Climate Change
- Formation of Supercontinent (Pangea)
- Glaciation
49Some pterosaurs had wingspans of up to 50 feet.
50Dinosaurs are often grouped into two main
divisions, Ornithischia and Saurischia, based
upon the structure of their hip bones.
Ornithischia
Saurischia
51Dinosaurs remarkable for their ecological
diversity.
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54Birds evolved from dinosaurs the only remaining
lineage of dinosaurs.
55Massive extinction at the end of the Cretaceous
marked the end of the dinosaurs, and made way for
mammals.
56Chicxulub crater site of impact 65 million
years ago.
57Mammals
First mammals evolved long before the Cenozoic,
from the Therapsids
58Diictodon
Cynognathus
Therapsids are often referred to as mammal-like
reptiles. They have teeth similar to mammals.Â
They have a stance similar to mammals (limbs
pulled under the body - a more efficient body
plan). Some even speculate that some latter
therapsids had hair, but the only evidence of
skin in a therapsid comes from a hairless, more
primitive species from the end of the Permian,
millions of years before therapsids went extinct.Â
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61Reconstruction of the skeleton of Megazostrodon,
one of the earliestmammals known. Megazostrodon,
with a body length of about 13 cm, is from the
Upper Triassic Red Bed series of the Karoo, and
was possibly a nocturnal, insect-eating animal.
Morganucodon
62All mammals have nearly identical bone structure.
Mostly just the relative sizes differ.
63Evolution of cetaceans a return to the water.
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65Echidna
Platypus
Monotremes egg-laying mammals.
66Tasmanian devil
Opossum
Kangaroo
Marsupials carry young in pouches.
67Land bridges allow for massive animal migrations.
68Cenozoic mammals have changed greatly along with
climate changes.
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70Apes and monkeys diverged about 30 million years
ago. Humans diverged from the other apes 10-13
million years ago.
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73The apex of evolution Humans?
74The apex of evolution Humans?
75What next?
Perhaps the lesson from dogs?
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