5 Major Extinctions


The Mesozoic era ended in what is almost certainly the most notable catastrophe ever, but the Cretaceous-Tertiary extinction was in fact only the most recent of the five major extinction-level events in Earth’s paleo-history.

First was the Ordovician-Silurian event; up until the Silurian period the only life on Earth lived in the extremely biodiverse seas of the Cambrian and Ordovician, primarily arthropods, but one animal called mikomingia. Mikomingia had no fins, teeth or eyes and was about the size of your thumbnail, but it had a backbone, making it the very first fish, and the earliest vertebrate. During the Ordovician, the seas had much more variety than in the Cambrian and one life form which would lead to the first major extinction. During this period the first plants started growing on land who performed photosynthesis at a remarkable rate which leads the majority of scientists to believe that the great dying happened as a result of the oxidising of the atmosphere. The Silurian period brought great change to the planet, obviously the fish and cephalopods still thrived but the arthropods, mainly land-based, had shrunken to animals recognisable today. Amphibians had also evolved and headed onto land.

The second of the major events was one of the smallest and happened midway through the Devonian period. There is much debate surrounding what caused this extinction because there were lots of possible causes at the time, for instance; asteroid storms, super-volcanoes and the movement of the tectonic plates could all have had a part to play in the Devonian event.

After the Devonian period came, the Carboniferous period came about, whilst not connected to any major extinction level events I still thought it was worth mentioning. During the bulk of the Carboniferous period the oxygen content of the Earth’s atmosphere was over 60% above what it is today, as a result of the extreme climate, plants like ferns and arthropods were able to sustain much larger bodies and the Earth was covered in swampy forests. Then you could’ve found spiders and scorpions the size of your head or, most infamously, creatures like Meganeura and Arthropleura. Meganeura would be recognisable today as a dragonfly, except with a wingspan of over a metre. Arthropleura, on the other hand, was an early ancestor of the millipede which, if it were to stand upright (or as upright as millipede can stand), would be over 2 metres tall.

The largest of the extinction events ended the Palaeozoic era and caused over 90% of animal life to be wiped out. The Permian was hot, and a stark contrast to the Carboniferous period before. By this time, lizards from the Carboniferous and late Devonian had evolved into a strange class of animals called synapsids. Synapsids were somewhere between mammals and reptiles, they moved like a mix between the two, some had tough skin and fur, other scales with smaller hairs. By the end of the Permian almost all large animal life were synapsids, but during the Permian-Triassic extinction event the globe began to heat up. Oceans dried up, drought and desertification brought the end of the synapsids. The only synapsids who survived were small burrowers, capable of extracting water from the last of the desert plants and after the extinction, during the Triassic, they would flourish.

When the Mesozoic era begun, with the Triassic period, the burrowing synapsids evolved into vast herds, spanning the globe. Lystrosaurus were the most successful species ever to have lived, throughout the Triassic period they ventured to every part of the world and were the only large herbivores, there were more of them then there ever have been humans and so their demise, along with of course the numerous carnivores who relied on them for food, made up the Triassic-Jurassic major extinction-level event. The synapsids died out due to the birth of a new species, who, via competition, eliminated such a momentous portion of animal life on Earth. These new reptiles were, of course, the dinosaurs which would dominate the planet for the rest of the era until they had their own extinction at the end of the Mesozoic.

During the next period, the Jurassic, dinosaurs ruled the land, huge marine reptiles the sea, and pterosaurs in the skies. It’s also between this period and the Cretaceous that we can see glimpses of the Earth as we know it today. In the Jurassic, the planet’s sixth super-continent, Pangaea, split up into the seventh super-continent, Gondwana, in the South and Laurasia, which made up Europe, North America and Asia. In the early Cretaceous period the first grasses evolve and later in the period bees and butterflies began pollinating the first flowering plants. During this era, the Himalayas and the Andes would grow, and the Atlantic was still expanding. But the pinnacle of life, the Mesozoic era, would eventually come to a close in the most infamous extinction event ever.

The Cretaceous period was mostly a dangerous and hostile planet, with super-volcanoes, climate change, an increasingly more toxic atmosphere and finally a comet which stuck the Gulf of Mexico and over a few weeks destroyed 75% of animal life. Still the Cretaceous-Tertiary extinction has left its marks on Earth including a boundary deep below the Earth’s surface and, of course, what came next. The Cenozoic era gave rise to some of the first mammals including the first human species, homo habilis.

But I have a concern which I share with many, which is that we are leading out planet towards a sixth major extinction-level catastrophe. It’s not a crazy as you might think that littering and deforestation could have a similar eventual affect to the third great dying. Nature will bounce back, as sad as it is, this isn’t about saving an animal you’ve never heard of in a place, far away in a place you’ve never been. This is about us fixing the problem we made for our own good. We need to learn how to save ourselves.

COP26 talk report

The green group were lucky enough to have Aled Jones, the dad of a Year 7 pupil and a very important person in sustainability who will be going to COP 26, join them over Microsoft teams to deliver a talk about climate change.

Firstly, Aled spoke about the Paris Agreement (a agreement between world leaders stating what they would do to save the environment in the next few years) and how it was relevant to COP 26 (a meeting in Glasgow in November this year where world leaders will make more pledges about what they will do for the planet, which will hopefully achieve enough this time).

Aled then talked about what the world has done in the last decade to combat climate change in several areas of the problem: energy, transport, forests, food, homes, jobs, waste, behaviour, community and leadership, and what we need to do in the next ten years. One interesting statistic is that, from less than 1 percent ten years ago, nearly half our lighting sales are now of efficient LED lights globally.

Lastly, Aled told the green group about a new book coming out which he had helped to organise. It was a series of letters from young people across the globe to world leaders, telling them what they want governments to do in the next decade. A Comberton pupil (Freya in 7N) has written one of the letters in the book. This book will be given to world leaders at COP 26.

All in all, it was a fascinating and informative talk. Thank you for coming to speak to us, Aled!

COP 26 Talk Report by Emily

On the 28th of April, the Eco Team met with Professor Aled Jones, director of the Global Sustainability Institute. Professor Jones gave a concise and informative presentation on what may be achieved in the upcoming COP26 (which he hopes to attend), as well as detailing the progress that has been made over the last ten years.
Professor Jones began by outlining the potential impacts of climate change and explaining what would happen with specific rises in temperature: from a one degree rise to six degrees. He then displayed a simple graph of the number of attendees of the previous COPs, adding that the coming COP26 is predicted to have 30,000 participants. Professor Jones explained that only a small fraction of this number would be made up of the governments themselves, and the majority of participants are usually academics like himself, business people, charities, protesters and people working in the media.
Professor Jones then outlined the successes and failures of previous COPs. He explained why COP15 was deemed a failure: despite a record 26,661 people turning up in the hope of agreeing on a “comprehensive framework” to implement moving forward, little was agreed upon except that governments would essentially keep talking to each other. He then explained that following this more meaningful agreements were made – notably the Paris Agreement. He then explained what the Paris Agreement actually involves (i.e. reducing greenhouse gases, limiting temperature rise to 1.5°C – 2°C, reviewing progress every five years, and investing $100 billion in climate finance to poorer countries by 2020).

Flexitarian – have you heard?

Thoughts from the EcoTeam’s Bella Fuerst

People say: eating less meat will help the environment. Eating no meat will be even better!

Do you think so too? Will you just believe it or will you do some research first to make up your mind? 

Maybe enjoy a magherita style pizza every other time? Or decide on the meet-free-Monday with your family?

The internet has so many meat free recipes to offer. Sure you can still have your bacon but becoming aware about the amount of meat you eat every week could make you change your habits over time and hopefully make a difference in the BIG scheme of things.

Fish is also an option. But will eating ‘just fish’ do the trick for the environment?

What’s your gut feeling? Wanna do some research?

From Greenpeace.org >

The livestock sector — raising cows, pigs and chickens — generates as much greenhouse gas emissions as all cars, trucks and automobiles combined. Cattle ranchers have clear cut millions of square kilometers of forests for grazing pastures, decimating natural “carbon sinks.”

Also this: “The research is clear — a diet heavy in meat increases the risk of obesity, cancer and heart disease.”

What you can do:

  • Commit to reducing your meat and dairy consumption by a few meals per week and tell five friends about your choice to find alternative proteins.
  • Make fresh fruits and vegetables a bigger part of your diet.
  • Buy sustainable or organic fresh produce whenever possible.

Green matters. After all, we only have one planet.

Bella F

EcoTeam member Mabel Fletcher’s take on fast fashion, and what we can do about it

Fast Fashion is ‘fast’ in multiple senses: rate of production is fast; customer’s decision to purchase is fast; delivery is fast; and items of clothing are worn fast, usually only a few times before being thrown away. Fast fashion is entirely unsustainable. 80 billion new garments are bought each year globally, and the UK buys more clothes than any other country in Europe. According to the Fixing Fast Fashion report, the fast fashion business is, “encouraging over-consumption and generating excessive waste.” The worst offenders in the UK market their clothes primarily to young people, especially young women, and are some of the newer brands such as Boohoo, Pretty Little Thing, Missguided, and Nasty Gal.

Fast Production. In the last 15 years, production of clothing has doubled, but at the same time the number of times a garment is worn before it is discarded has decreased by 30%. We are creating more clothes, buying more clothes, and wearing them less. Fast fashion business models offer hundreds of new products, every week, or even every day. The short lead times necessary to deliver such vast quantities of new designs means that wash tests and wearer trials are usually not possible. This has implications for garment quality and durability. In addition, many of the products are made with materials that cannot be recycled.

‘Reshoring’ and worker exploitation. While most fashion companies still source the majority of their garments from overseas, some fast fashion brands such as Boohoo, Missguided and ASOS, have ‘reshored’ a substantial part of their production, sourcing garments from the UK, with many products being made in Leicester. Leicester is one of the UK’s textile manufacturing hubs, employing 10,000 textile workers in 700 factories. Many of the large buildings where manufacturing takes place do not house just one factory, but a whole load of mini factories, up to a hundred, each employing around 10 to 20 people. The sourcing from the UK means these online retailers can drastically reduce their lead times, allowing them to quickly react to changes in consumer tastes. An exposé by the Financial Times in 2018 discovered workers at factories in Leicester were paid as little as £3.50 an hour, under half the minimum wage for people aged 25 and over. Trade Union Unite points out, “in ‘high wage countries’ clothing producers continually attempt to drive down wages for profit.” It is no surprise that fast fashion brands were found to be relying on a workforce comprising largely of migrant, temporary workers, who are underpaid and overworked. Boohoo and Missguided were approached and asked to respond to the issues of worker exploitation. Missguided stated that it joined the Ethical Trade Initiative (ETI) in 2017 and had since consolidated the number of factories in Leicester from 81 to 11. However, Boohoo remained reluctant to join the ETI. Boohoo received Ethical Consumer’s worst rating for Supply Chain Management. Missguided received a middle rating, which was based on an assessment of each company’s Supplier Code of Conduct and other polices relating to managing their supply chains.

Fixing Fashion: Clothing Consumption and Sustainability. In February 2019, the House of Commons Environmental Audit Committee released a damning report on the fashion industry, ‘Fixing Fashion: Clothing Consumption and Sustainability.’ The report examined the environmental and social costs of the fashion industry, especially fast fashion. It made a number of recommendations to the government, many of which argued for legislation to secure business compliance, as opposed to the failed system of voluntary cooperation in place at present. Some examples of the key recommendations: a Sustainable Clothing Action Plan (SCAP) should be made mandatory for all retailers with a turnover of more than £36 million (rejected), a ban on incinerating or landfilling unsold stock that can be reused or recycled (rejected), a charge of one penny per garment on producers in order to raise investment for better clothing collection and sorting in the UK (rejected). As you can see, all were rejected.

Fast purchasing and fast use. Purchasing items of clothing is now easier than ever, facilitating mass overconsumption. Fast fashion brands make heavy use of social media platforms, where users are able to purchase the clothes they see upon the bodies of models and ‘influencers’, in just a few swipes of the finger or thumb. Low prices mean that buying an item requires little consideration. Even those without the money can have what they desire in the world of fast fashion with the wide availability of online credit. Delivery is fast and relatively cheap, which allows customers to have what they want the day after they buy it. Boohoo, Pretty Little Thing, Missguided and ASOS all promote delivery services that offer a year of unlimited, next day delivery for under £10. The garments produced in the world of fast fashion are generally of low quality, but many are thrown out before they have a chance to be worn out. The average person buys 60% more items of clothing than they did 15 years ago, but that clothing is kept only half as long. This problem is worse among younger generations. A study commissioned by Barnardo’s suggested that a quarter of people would be embarrassed to wear an outfit to a special occasion more than once, but this figure rises to 37% for young people aged 16-24 and falls to just 12% for over 55s. Another study found that 17% of questioned young people said they wouldn’t wear an outfit again if they’d already posted it on Instagram. This is a big issue.

Fast fashion during the Covid-19 pandemic. Unfortunately, things have not gotten any better due to the pandemic. Fashion brands are still not paying suppliers and are still not paying workers enough. Many clothing brands have responded to the pandemic by refusing or delaying payments to suppliers, and some factories are completely ignoring Coronavirus restrictions. Thulsi Narayanasamy, Senior Labour Rights Lead at theBusiness & Human Rights Resource Centre, said: “We are long past the time when a ‘we’ve-not-had-time-to-prepare’ defence will wash […] Our findings show the fashion industry thinks it can continue with a ‘business-as-usual’ approach, sticking to the same policies and practices they used before the pandemic. But what garment workers are facing is nothing short of complete upheaval and crisis. For workers, already paid so little, to lose their jobs or not receive a full wage is the difference between feeding your family or not.”

CVC meets the Wildlife Trust

The Comberton EcoTeam virtually welcomed Becca Neal of the Cambs, Beds and Northants Wildlife Trust at an online event on Wednesday 25th November. Becca gave a detailed overview of how climate change is having an impact locally, discussed what the Wildlife Trust is doing to combat it, and inspired attendees with some excellent tips about how they can get environmentally active. These included fund-raising ideas and suggestions to get out and experience nature at every opportunity. Thank you, Becca, for such an engaging and thought-provoking talk!

More details of the amazing work the Wildlife Trust is doing can be found here: https://www.wildlifebcn.org/

Attending the Youth Climate Summit: what we learnt

Sustainable Fishing

Sustainable fishing is when fishermen don’t take a ridiculous amount of fish from the ocean, and use boats that have a very low carbon emission .Surprisingly very few actually do this as most overfish and often use boats that excrete ridiculous amounts of CO2 overfishing has been happening for hundreds of years. It is when a species of fish is removed faster than it can reproduce, which can eventually lead to extinction if overfishing is not managed. Overfishing can mess up entire food chains as often the larger predatorial fish are fished for and the smaller fish aren’t even bothered with because they are so small so they slip through the nets. At the present it is such a problem that 90% of large fish have been lost and by 2048 if we are to continue at the rate we are fishing now, all the world’s entire oceans could be emptied. The most destructive method of overfishing is called bottom trawling. This is when a large fishing net is dragged along the floor of the ocean, ripping up plants and animals from the floor. It affects slow growing habitats the most as often these won’t grow back. Plants under the water also photosynthesise, a process where the plant absorbs co2 and excretes oxygen, so when trawling is used and it rips ups these plants and the plants release the CO2 into the atmosphere. When bottom trawling is used it can often catch larger fish, and even though once the fishermen realise that they have caught them they put them back in the ocean, often these fish are injured or killed during the process. We need to stop supporting these harmful fishing companies and start trying to be more sustainable with our fishing.

Aurora Pitalis-Bliss and Becca Davies, Year 8

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