BIOL 1010 Introduction
to Biology: The
Evolution and Diversity
of Life. Spring 2011
Sections A & B
Steve Thompson: [email protected]
http://www.bioinfo4u.net
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Wednesday, March 2, 2011
So far this semester we’ve talked
about how and why life evolved,
and we’ve started on a survey of
life, beginning with the huge
diversity of Bacteria and
Archaea . . .
all unicellular, without their DNA
contained in a nucleus, (and incorrectly
called ‘prokaryotic’) organisms . . .
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Wednesday, March 2, 2011
But what about all the rest of life . . .
The Eukaryotes! Their diversity,
their complexity, their unity.
Eukaryotes are all of organismal life
that have their DNA contained in a
membrane-bound nucleus (and also
usually other DNA in membranebound organelles, the mitochondria,
and perhaps chloroplasts).
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Wednesday, March 2, 2011
“Eukaryotes are . . .
Organisms whose cells contain a nucleus and other
membrane-bound organelles. There is a wide range of
eukaryotic organisms, including all animals, plants,
fungi, and protists, [and] algae. Eukaryotes may be
either single-celled or multicellular. Eukaryotes are
differentiated from [Bacteria and Archaea] by way
of the presence of internal membranes that separate
parts of the eukaryotic cell from the rest of the
cytoplasm. These membrane-bound structures are
called organelles.” From: http://www.nature.com/
scitable/definition/eukaryote-294
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Wednesday, March 2, 2011
“In eukaryotes, the cell's genetic material, or DNA, is
contained within an organelle called the nucleus, where
it is organized in long molecules called chromosomes.
Eukaryotic cells also contain other organelles, including
mitochondria, which generate energy; the endoplasmic
reticulum, which plays a role in the transport of
proteins; and the Golgi apparatus, which sorts and
packages proteins and lipids for transport throughout
the cell. Plant cells additionally contain organelles
called chloroplasts, which are used to collect energy
from sunlight.”
From: http://www.nature.com/scitable/definition/
eukaryote-294
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Wednesday, March 2, 2011
They come in all
shapes and sizes . . .
A bunch that we never knew
were there, many of which are
called “protists,” all the way up
to huge things like blue whales,
kelp beds, and giant sequoias.
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Wednesday, March 2, 2011
What are the major
groupings of Eukaryotes?
Note that the polyphyletic grouping used by your author, “protists,”
lumps together most unicellular, nucleated organisms. Check out how
the protists actually appear all over the “Tree” at:
http://tolweb.org/Eukaryotes/. We’ll look at them more in a bit.
Take a while here to check out the common characteristics of
Eukaryotes and their amazing diversity on the “Tree of Life.”
Here are the major divisions according to ToL:
1. A clade of all animals, fungi, and a bunch of obscure protists.
2. A clade of algae – both green and red – and all land plants.
3. Another clade of algae, and what, more protists!
4. And what else, oh no, not another protist clade.
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Wednesday, March 2, 2011
And another Eukaryotic “Tree of Life”
http://www.ucmp.berkeley.edu/alllife/eukaryotasy.html
disagrees a little on the ordering, but the groups are still there.
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Wednesday, March 2, 2011
Here’s the Eukaryotic tree from
Simpson and Roger (2004).
“The real ‘kingdoms’ of eukaryotes”
Volume 14, Issue 17, 7 September 2004, Pages R693-R696
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Wednesday, March 2, 2011
And a
wonderful
interactive
Eukaryotic tree
from the Katz
Lab at Smith
College.
http://
www.science.smith.
edu/departments/
Biology/lkatz/
EuTree2009/
Eutree09.html
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Wednesday, March 2, 2011
Here are the group names – don’t even try to memorize them!
There are t wo groups of more familiar organisms:
1) Unikonta includes:
Opisthokonta: single flagellum in the trailing direction,
when present, which includes —
Metazoa (all animals, including us!); and . . .
Choanoflagellates (collar flagellates); and . . .
Fungi (and some miscellaneous protists). Plus . . .
Amoebozoa: some amoebas and true slime molds.
2) Plantae (also called Archaeplastida): plastids directly from
an ancestral Cyanobacterium , which includes —
Viridiplantae: green algae and land plants; and . . .
Rhodophyta: red algae; and . . .
Glaucophytes: a unique microalgae protist.
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Wednesday, March 2, 2011
And all the other polyphyletic algae and protists:
3) Chromalveolata: largely photosynthetic, mostly unicellular, protists;
SAR (Stramenopiles, Alveolata, Rhizaria), may be polyphyletic.
Chromista (plastids of secondary endosymbiotic red algal origin):
Stramenopiles or Heterokontophyta (golden algae, diatoms, brown
algae like kelp, water molds, etc.)
Haptophyta: Coccolithophores
Cryptophyta: Cryptomonads
Alveolata:
Ciliophora: ciliates like Paramecium
Apicomplexa: includes the malaria and toxoplasmosis parasites
Dinoflagellata: some of them make dangerous "red tides"
Rhizaria; they make long thin strands and are often shelled:
Cercozoa: amoeboflagellates
Foraminifera: amoeboid with calcium carbonate shells
Radiolaria: amoeboid often with glass shells
4) Excavata: most have feeding grooves on them. They include Giardia,
Euglenids, Jakobids, Diplomonads, Oxymonads, etc.
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Wednesday, March 2, 2011
Here’s some
pictures from
a really nice
article in PLOS
Genetics,
“Evaluating
Support for
the Current
Classification
of Eukaryotic
Diversity.”
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Wednesday, March 2, 2011
http://
www.plosgenetics
.org/article/
info:doi/10.1371/
journal.pgen.
0020220
It’s nowhere near definitive.
Wikipedia has a pretty decent overview at http://
en.wikipedia.org/wiki/Eukaryote — “There are still
uncertainties in the evolutionary history and
classification of eukaryotes.”
The big thing to remember is it all began with
endosymbiotic events and other horizontal genetic
swapping stuff. This cumulatively led to
compartmentalization. And once the Eukaryotic cell got
started, it originated another huge wave of
diversification, especially of structure!
Here’s a great recent article: http://
www.science.smith.edu/departments/Biology/lkatz/
documents/Yoon_EuTree_2008%201.pdf
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Wednesday, March 2, 2011
So, let’s launch right in on
a look at a slew of those
crazy protists . . .
Spread all over the Tree of Life. We’ll
see just how varied they are — their
wild shapes and forms and lifestyles.
We’ll see how far we get, and then
continue next time, along with the
Exam II review.
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Wednesday, March 2, 2011