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Notes on video lecture:
Diversity of Early Vertebrate Life
Choose from these words to fill the blanks below:
shells, survive, iron, eyes, flattened, two, Metaspriggina, ventral, multicellular, starfish, radial, heads, Burgess, microbial, 542, directly, vertebrates, soft, brain, billion, destroyed, microbes, Mesozoic, concentrated, bundles, weave, explosion, blurrier, lottery
as paleontologists look back into the past, the further they look, the                  and smaller the view finder becomes
with living animals we can observe them                 
with animals from the Paleozoic Era (542-250 Ma, fish) or                  Era (250-65 Ma, dinosaurs) we observe them through fossils
becoming a fossil was like striking the               
as some soft Paleozoic life form, the chances of your remains being preserved was exceptionally small
and after a fossil was formed, it had to beat the odds again and again throughout the eons to                until it was eventually be uncovered and studied
there is about a half                years between the first appearance of vertebrates in the fossil record and today
during this time, sediments and their fossils were regularly                   
localities of exceptional preservation are all the more valuable for what they can tell us
we call these areas of exceptional preservation Lagerstätten
a German word that means storage place
it's only through specific Lagerstätten that we know anything about the earliest animals and                       
because these were animals that were all         -bodied
such localities are snapshots which afford us a brief glance of life at specific times of our Earth's history
the first evidence of life that we have in the fossil record is that of                 
640 million years ago
bacteria and other single-celled organisms dominated the earth from around 3.8 billion years ago to 640 million years ago
life was mostly made up of                    mass
on a twelve hour clock of evolutionary scale, higher animals don't show up until about 10:00, only        hours of evolution
before that it was only microbes
Ediacaran Period (635-       Ma)
first                            life
first appearance worldwide of somewhat complicated trace fossils
Cambrian Period (542-485 Ma)
rapid diversification of lifeforms known as the Cambrian                   
high proportion of Lagerstätte sedimentary deposits with exceptional preservation
               Shale biota (508 Ma, middle of Cambrian Period)
soft-bodied organisms
first appears over 600 million years ago
first organisms to produce             
modern animals
have anterior and posterior end
dorsal and               
bilateral
bilateral animals like fish have           , while radial animals like sea urchin don't
bilateral animals move forward or backward
             animals more in any direction
therefore for bilateral animals, sensory organs become                          at the anterior end
most animals are bilaterally symmetrical
exception are echinoderms, e.g.                 
some early fossiles are bilateral and are probably our ancestors
Cambrian Explosion
complex and multicellular life began to diversify in the Pre-Cambrian supereon
increased heavily in the Cambrian period (after 542 Ma)
increase in level of oxygen in oceans and atmosphere
rising sea levels
shallow water environment
animals evolved hard parts
enabled them to have protect themselves and rise up to the surface
Burgess Shale
shales deposited more than 500 million years ago
cliffs of the reefs protected it when the Rocky Mountains formed
animals lived in still water
                   impressions of the animals
black color films made of         -rich minerals
traced the outline of the soft tissues
closest relative of living vertebrates
                          
two large         
vertebrae-like structures in the back
a large            in front to process information from the eyes
segmented muscle               
-myomeres
could            their way through the water

Ideas and Concepts:

On the unlikelihood of becoming a fossil, via tonight's Early Vertebrate Evolution class:

"For animals from the Paleozoic Era (542-250 million years ago), becoming a fossil was like striking the lottery. As a soft life form, the chances of your remains being preserved beyond even a few years was exceptionally small. And in the unlikely event that a fossil of your remains was formed, it had to beat the odds again and again throughout the eons to survive until it was eventually be uncovered and studied.

There are about a half billion years between the first appearance of vertebrates in the fossil record and today. During this time, sediments and their fossils were regularly destroyed. Therefore, localities of exceptional preservation are all the more valuable for what they can tell us about life in these eras.

We call these areas of exceptional preservation Lagerstätten, which is a German word that means storage place. It's only through specific Lagerstätten that we know anything at all about the earliest animals and vertebrates. Because most of these animals were soft-bodied life forms, such localities are rare snapshots which afford us a brief glance into the life at specific times of our Earth's history."
The Origin of Vertebrates
Vertebrate Environments
Diversity of Early Vertebrate Life