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A chimeric photoreceptor gene, NEOCHROME, has arisen twice during plant evolution -- Suetsugu et al. 102 (38): 1370
- Published online before print September
8, 2005, 10.1073/pnas.0504734102
- From The Cover
- PLANT BIOLOGY
- A chimeric photoreceptor gene, NEOCHROME, has arisen
twice during plant
evolution
- Noriyuki Suetsugu *, Franz
Mittmann , Gottfried
Wagner , Jon Hughes ,
and Masamitsu
Wada *, ,
- Although most plant species from algae to flowering plants use
blue light for inducing phototropism and chloroplast movement,
many
ferns,
some mosses, and green algae use red as well as blue light for
the regulation of these responses, resulting in better sensitivity
at low light levels.
- evolution
- ferns
- However, the
fern and algal genes seem to have arisen independently in
evolution,
thus providing an intriguing example of convergent
evolution.
- evolution
- ferns
- ferns
- evolution
- evolution
- View larger version
- Fig. 1.
- View this
table:
- Table 1.
- ferns
- ferns
- View larger version
- Fig. 2.
- evolution
- View larger version
- Fig. 3.
- View larger version
- Fig. 4.
- ferns
- ferns
- ferns
- This article has been cited by other articles in HighWire
Press-hosted journals:
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The Carboniferous [Upload 080530]
- The Carboniferous Period occurred from about 354 to 290 million years
ago during the late
Paleozoic
Era.
- The term "Carboniferous" is used throughout the world to describe
this period, although this period has been separated into the
Mississippian (Lower Carboniferous) and the Pennsylvanian (Upper
Carboniferous) in the United States
- term "Carboniferous", or
"carbon-bearing"
- an increase in the number of tree ferns
- Godwanaland (present-day Africa
and South America)
- Plant material did not decay when the seas covered them and pressure
and heat eventually built up over the millions of years to transform the
plant material to coal.
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No
- The appearance or disappearance of fauna usually marks the boundaries
between time periods.
- Coal beds, which can be up to eleven to twelve meters thick, characterize
the Upper Carboniferous.
- The forests
of seedless vascular plants that existed in the tropical swamp forests of
Europe and North America provided the organic material that became
coal
- Index fossils are the remains of plants and animals that
characterize a well-defined time span and occur over a wide range of
geography
- coal forests
- The Carboniferous was marked by the progressive formation of the
supercontinent Pangea
- Laurasia
- Gondwana
- Great coal-forming forests developed as a result of rare freezing
temperatures and a warm, humid climate. In the closed swamps, accumulating
layers of decaying plant matter produced numerous layers of coal.
- One of the greatest evolutionary innovations of the Carboniferous
was the amniote egg, which allowed for the further exploitation of the land
by certain tetrapods. The amniote egg allowed the ancestors of birds, mammals,
and reptiles to reproduce on land by preventing the
desiccation of the embryo inside.
- Scale trees (lepidodendrons) grew to 35 meters (115 feet) forming
dense forests
- Entire content Copyright © 1998-2006
ADR & Associates
Abiding Dave's Science World at Science501.com
All rights reserved. Protected by the copyright laws of
the United States and International Treaties.
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Climate during the Carboniferous Period
- The hot and humid climate of the Middle Carboniferous
Period was accompanied by an explosion of terrestrial plant life.
- 100
or so coal seams which today comprise the Great Bituminous Coalfields of
the Eastern U.S. and Western Europe.
- The explosion of luxuriant plant growth
and coal bed formation that occurred 286 - 360 million years ago is the reason
for the name, "Carboniferous Period."
- Similarly, atmospheric concentrations of carbon dioxide (CO2)
in the Early Carboniferous Period were approximately 1500 ppm
(parts per million), but by the Middle Carboniferous had declined
to about 350 ppm -- comparable to average CO2 concentrations
today!
- Earth's atmosphere today contains about 370 ppm CO2 (0.037%).
- Late Carboniferous to Early
Permian time (315 mya -- 270 mya) is the only time period in the last
600 million years when both atmospheric CO2 and temperatures
were as low as they are today (Quaternary Period
)
- There has historically been much more CO2 in our atmosphere than
exists today. For example, during the Jurassic Period (200 mya), average
CO2 concentrations were about 1800 ppm or about 4.8 times higher than
today. The highest concentrations of CO2 during all of the Paleozoic Era
occurred during the Cambrian Period, nearly 7000 ppm -- about
19 times higher than today.
- The Carboniferous Period and the Ordovician Period were
the only geological periods during the Paleozoic Era when
global temperatures were as low as they are today. To the
consternation of global warming proponents, the Late Ordovician Period was
also an Ice Age while at the same time CO2 concentrations then were
nearly 12 times higher than today-- 4400 ppm. According to greenhouse
theory, Earth should have been exceedingly hot. Instead, global temperatures
were no warmer than today. Clearly, other factors besides atmospheric carbon
influence earth temperatures and global warming.
- Two special conditions
of terrestrial landmass distribution, when they exist concurrently, appear
as a sort of common denominator for the occurrence of very long-term
simultaneous declines in both global temperature and atmospheric carbon
dioxide (CO2):
- 1) the existence of a continuous continental
landmass stretching from pole to pole, restricting free circulation of polar
and tropical waters, and
- 2) the existence of a large
(south) polar landmass capable of supporting thick glacial ice
accumulations.
-
- These special conditions existed during the Carboniferous Period,
as they do today in our present Quaternary Period.
- We are actually in an ice age climate today. However for the
last 10,000 years or so we have enjoyed a warm but temporary
interglacial
vacation. We know from geological records like ocean sediments and ice
cores from permanent glaciers that for at least the last 750,000 years
interglacial periods happen at 100,000 year intervals, lasting about 15,000
to 20,000 years before returning to an icehouse climate. We are currently
about 18,000 years into Earth's present interglacial cycle. These cycles
have been occurring for at least the last 2-4 million years, although the
Earth has been cooling gradually for the last 30 million years.
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Carboniferous period. The Columbia Encyclopedia, Sixth Edition. 2001-05
- The plant life of the Carboniferous period was extensive and
luxuriant
- more than 800 kinds of
cockroaches
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Earth's First 3.7 Billion Years: Lecture 7
- The two essential elements of Life are that the system needs to be
able to replicate and it needs to be separated from its surroundings.
- Evidently, photosynthesis must have started nearly at the beginning.
At once that changed the world because of the release of free oxygen.
- Eukaryotic cells are symbiotic colonies of prokaryotes; many of the
symbionts are called organelles. O2 is handled by Mitochondria, chloroplasts
handle photosynthesis. These organelles independently replicate with their
own genome DNA sequences in circular strands, as in bacteria.
- During the peak of land plant spread, in the Late Carboniferous
(300 million years ago), the world plunged into a long glacial age, almost
certainly due to plant-mediated weathering.
- The end of the Permian saw the greatest mass extinction
of all time.
- Raup has estimated that perhaps 99% of
all species went extinct.
- The origin of this mass extinction is unknown, however, there is
speculation that massive amounts of CO2 and sulfuric acid released by the
massive volcanism that produced the Siberian Traps (basalts) may have contributed
by causing sever climatic disruption.
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Evolution of Plants [Upload 080530]
- Like animals, the steps most pertinant to the invasion of land appear
to have involved the evolution of desiccation resistance.
- Kinds of plants:
- Based on the presence of these various, sophisticated adaptations,
plants may be categorized as follows:
- nonvascular plants versus vascular plants
- vascular non-seed bearing and vascular seed bearing
- seed bearing non-flowering and seed bearing flowering
- The most advanced plants are considered to be the flowering vascular
plants while the most primitive plants are considered to be the nonvascular
plants.
- There exists approximately 275,000 individual species of flowering
plant out of about 325,000 species of plants. Clearly, especially given their
tendency toward extremely macroscopic bodies, flowering plants are the dominant
terrestrial producers.
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Patterns of segregation and convergence in the evolution of fern and seed plant leaf morphologies Paleobiology
- the
separation of vegetative and reproductive roles into distinct organs in later
seed plant groups may have allowed greater functional specialization-and
thereby morphological simplification-as the seed plants came to be dominated
by groups originating in more arid environments
- During the Late Devonian and Early Carboniferous, at least four vascular
plant line-ages (seed plants, progymnosperms, ferns, and sphenopsids)
independently evolved laminate leaves and followed the same early sequence
of morphological evolution
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Carboniferous period: Historical Geology of the Period
- Carboniferous
is often split into two divisions, the Mississippian and the
Pennsylvanian
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Mountains formed by plate convergence
- Although this ancient mountain range has been subsequently reduced
to nothing by the forces of wind and rain, it's height and extent are believed
to have equaled or exceeded the Himalayas of today
- By 250 million years ago all the continental landmasses on earth
had converged to form the single supercontinent Pangea. About 213
million years ago, during the Jurassic Period, Pangea began breaking apart
and the continents began to reassemble themselves into new landmasses which
comprise the continents we have today
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Moving Continents: Images of Continental Drift
- The phenomena is known as continental drift and the process
has been going on for hundreds of millions of years-- at rates measured in
only a few centimeters per year.
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The Paleozoic Era
- The Paleozoic is bracketed by two of the most important events in
the history of animal life. At its beginning, multicelled animals underwent
a dramatic "explosion" in diversity, and almost all living animal phyla appeared
within a few millions of years
- At the other end of the
Paleozoic, the largest mass extinction in history wiped out approximately
90% of all marine animal species
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Permian HSU NHM
- Plate
Tectonic Reconstructions
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