The Learn Tracker
...life-long learning: structured, organized, searchable...
922
Lectures Watched
Since January 1, 2014
Hundreds of free, self-paced university courses available:
my recommendations here
Peruse my collection of 275
influential people of the past.
View My Class Notes via:
Receive My Class Notes via E-Mail:

VIEW ARCHIVE

Contact Me via E-Mail:
edward [at] tanguay.info
Notes on video lecture:
Diversity of Early Vertebrate Life
Notes taken by Edward Tanguay on July 23, 2019 (go to class or lectures)
Choose from these words to fill the blanks below:
lottery, soft, radial, microbes, bundles, Mesozoic, flattened, Burgess, directly, destroyed, shells, vertebrates, blurrier, survive, Metaspriggina, concentrated, 542, billion, starfish, weave, brain, iron, explosion, microbial, eyes, ventral, heads, multicellular, two
•
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