Key Messages
Discover The Fascinating History Of Plant Evolution: Exploring 400 Million Years Of Plants, Animals, And Climate Change
In Tom Weller’s 1985 book Science Made Stupid, he claimed that the evolution of plants is a dull topic to cover.
However, in The Emerald Planet you’ll discover how plants have influenced major changes to the environment throughout history and in our current times.
You’ll learn about the interconnected history between plants, animal life and climate by examining snapshots from 400 million years ago up to the present day.
Get a deeper understanding of mass extinction events and global warming through facts like why leaves got bigger 375 million years ago, how giant insects came to be and what might have caused a large hole in the ozone layer.
By progressing through these sections, you’ll be more informed on how best to tackle our environmental situation today.
The Evolution Of Leaves: How A Drop In Carbon Dioxide Led To A Plant Revolution And The Evolution Of Animals And Insects
The reason that animals and insects were able to begin evolving was due to plants’ response to a decrease in carbon dioxide levels.
Through tiny pores located on the surface of their leaves, known as stomata, plants can absorb CO2 if levels decrease.
As such, plants are constantly adjusting to the changing environment by responding with an increase in the number of stomata in their leaves – if CO2 levels are low, then more stomata must be present in order for the plant to capture it effectively.
In addition, older leaves can even communicate with younger ones, telling them how many stomata to make when necessary – making sure that the new generation of plants is best adapted for the current global climate.
Approximately 375 million years ago, enormous drops were seen in atmospheric CO2 levels which made photosynthesis far less effective than before.
Plants had no choice but to increase the number of stomata in their leaves dramatically so as not to miss out on any carbon dioxide taken from the atmosphere – thus leading to bigger and more efficient leaves.
This caused an evolutionary boom of animal and insect species and tea seed a thriving flora around emerging ecosystems.
The Carboniferous Period: An Oxygen Spike Caused Gigantism In Ancient Creatures
When it comes to understanding why living organisms during the Carboniferous Period grew to such large sizes, a key element is the spike in oxygen levels that occurred during this time.
Specifically, evidence shows that oxygen levels rose to 35 percent around 300 million years ago before dropping again to 15 percent some 200 million years later.
And it was this increase in atmospheric oxygen concentration that enabled so much supergrowth.
In terms of what caused this spike, scientists point to plant evolution as the likely culprit.
As plants evolve and photosynthesize, they release more and more oxygen every day.
When organisms die and decompose, most of this oxygen gets used up – but not all of it; some is left behind and builds up over millions of years until it’s at levels high enough for a boost in atmospheric pressure – allowing all living organisms during this period to grow bigger than ever before!
Destruction Of The Ozone Layer Caused Mass Extinction And Genetic Mutations During The Permian Period
At the end of the Permian Period, approximately 250 million years ago, oxygen levels dropped to just 15 percent – one of their lowest point ever, resulting in the death of 95 percent of all species on Earth.
But researchers began to uncover evidence that some species had not been wiped out – they had mutated in response to a major global event.
After years of research examining animal fossils, Dutch paleontologists shifted their focus to plants, where they discovered something remarkable: plants surrounded by lycopsids, a type of short green plants with spiky leaves, which had developed into an asexual form of reproduction.
Through this surprising mutation, these plants were able to survive and even flourish in the harsh conditions caused by the destruction of the ozone layer due to volcanic eruptions and chemical reactions.
The clue that links it all is the destruction of the stratospheric ozone layer by ultraviolet radiation.
This was caused by 500 thousand years worth of volcanic eruptions producing organohalogens which interrupts ozone production and finally leads to mass {extinction}as well as genetic mutations among certain species.
Therefore it is evident that destruction of the ozone layer served as an important factor in initiating widespread extinction and genetic changes among many forms of life during this time period.
The Third Mass Extinction: Global Warming, Methane Hydrates And The Rise Of The Dinosaurs
Research conducted on ancient fossilized plants have shed new light on the long-proposed theory that a massive increase in CO2 levels was responsible for the extinction of many species of animals prior to the dawn of the dinosaurs.
The traces of carbon dioxide found in these fossils reveal a dramatic spike in atmospheric concentrations from what had been an average level up until this time.
This abundance of carbon dioxide caused global temperatures to rise, and with it brought about significant changes in climate which had disastrous effects for ancient animal life.
As CO2 levels rose, large-leaved trees could no longer keep cool and overheated, eventually perishing from the increased heat.
Smaller plants then replaced them, better adapted to deal with higher temperatures.
It is thought that huge volcanic eruptions triggered this crisis by releasing methane hydrates into the atmosphere which was then converted into more CO2.
Not only did this process result in higher temperatures but also acidified the oceans, causing coral reefs to die and further reducing oxygen levels so that marine life could not breathe.
With fewer resources available, those animals who were able to adapt were able to flourish, leading to a world dominated by dinosaurs.
Why Deciduous Trees Dominated The North Polar Forests: Fast Growth And Forest Fires
Deciduous trees adapted in an impressive way to survive the high northern latitudes of the North Pole.
Instead of adapting to store energy for a longer period, as evergreen trees do, deciduous plants opted for a “high-risk, high-reward strategy” by growing fast and dying young.
Computer simulations show that shedding leaves costs 20 times more than keeping them but such trees were able to take advantage of the short summer months by quickly photosynthesizing and recouping their lost energy throughout the year.
In terms of available sunlight, deciduous plants become quick winners compared to evergreen trees.
Another decisive factor was forest fires which give deciduous a newly clear area where they can repopulate right away while evergreen find it difficult to regain control over their territory which gives them even fewer chances of survival.
As climate change moves farther away from us, polar climes are slowly following suit with winters becoming warmer and snow melting quicker creating fertile soils where deciduous trees find little competition and spread easily leading them to dominate the landscape in the northern spots on our Emerald Planet.
How Rising Levels Of Greenhouse Gases Warming The Earth 50 Million Years Ago Led To A Drastic Change In Climate
Approximately 50 million years ago, our planet experienced a dramatic climate shift.
This shift resulted in a climate vastly different from today’s — one that was much hotter than the current climate.
Scientists believe that the key to this transformation lies in an increase of greenhouse gases in our atmosphere.
Greenhouse gases are substances that trap heat and warm the Earth up.
Examples of greenhouse gases include carbon dioxide, methane, ozone, and water vapor.
Of all these gases, carbon dioxide is the best known because it’s the most prominent one in our atmosphere at present.
While each of these greenhouse gases were important on their own during this period of climate change, together they created a powerful feedback loop – a cycle where warmer temperatures led to even more plant growth and animal life, leading to higher concentrations of greenhouse gas which then created further warming effects.
The role plants played cannot be understated – as mentioned earlier, mild temperatures led to more global vegetation growth than currently exists today.
As plants and animals died off over time, so did these microbes which released even more greenhouse gas into the atmosphere.
What eventually cooled things down? Another drop in carbon dioxide levels caused by too few plants to sustain the warming process appears to be the culprit behind leaving this “hot house”.
Glaciers began forming again as sea levels sank by around 100 meters and this drop brought much colder temperatures with it – freezing total polar regions while making tropics hotter climatically speaking.
How Cannes (C4) Photosynthesis Help Us Feed The World?
When plant’s photosynthesize, they convert carbon dioxide (CO2) and sunlight into energy.
But while most plants do this through the same method of photosynthesis, some have developed a more efficient way.
A process known as C4 photosynthesis enables tropical grasses and at least 7500 species of other plants to thrive when CO2 levels are low.
C4 plants are able to manufacture four atom long carbon molecules instead of the three atom long ones used by non-C4 plants.
This improved system was adapted in response to ecological changes such as a decrease in atmospheric CO2 concentration about 30 million years ago.
As their C3 counterparts couldn’t function well under these conditions, C4 plants were able to flourish compared.
So how did this evolutionary change happen? Some think that its success may be partly attributed to forest fire – as flammable grasses would recover more quickly than trees, they would have occupied the space left after a fire passed and climate change had been accelerated by this intricate feedback loop of events.
Today, humans depend on these C4 plants for our livelihood – crops like sugarcane and maize, which drive many economies all over the world, utilize this method of photosynthesizing.
With global warming likely rising in the coming years, scientists seek alternative ways to modify existing C3 crops with enhanced C4 features so that they too can become more adaptive and efficient – thus providing more people with food without sacrificing the environment!
Wrap Up
The Emerald Planet by David Beerling summarises the complex and intriguing history of our planet Earth, and how small changes in the environment can shape the lives of all plants, animals, and microorganisms living on Earth.
The book explains how drastic spikes and drops in CO2 levels have resulted in massive transformations in the atmosphere, leading to giant floras and faunas created by high oxygen levels as well as mass extinctions caused by climate change.
The book highlights that even though much about these immense changes remains a mystery, recent evidence has allowed us to gain a better understanding of Earth’s past to help us comprehend the current state of our planet.
