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- Herausgeber: The O'Brien Press
- Kategorie: Lebensstil
- Sprache: Englisch
- Veröffentlichungsjahr: 2021
Wildlife expert Eanna Ni Lamhna takes us on a tour of all things to do with our wonderful natural world: from a celebration of our fascinating birds and bees, and their powers of migration and pollination, to the thorny challenges of our time, such as climate change, sustainability and our carbon footprint. Her mantra is that learning about Our Wild World is not just for young children or David Attenborough fans, it is a lifelong necessary knowledge for our survival – and we need to open our eyes and our minds to the challenges that face us and our world into the future. The key is to find the balance between our needs and wants and the future of our precious planet and all its inhabitants. This brand new book raises, and discusses, questions such as; Why should we care about this natural world? Do we need and value the great outdoors now more than ever? But who wants spiders in their house? And what use are wasps anyway? Should we be worried by genetic engineering and windfarms? Biodiversity – what did it ever do for us? Does it mean the end of the world if the whales become extinct? Are global warming and climate change the same thing? What happened to the hole in the ozone layer? Is veganism the answer to sustainable food? What is carbon sequestration – just fancy words for trees? And why are carbon sinks so important? Is the mobile phone taking over our lives for good or for evil? How does a virus become a pandemic, and why?
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Dedication
For my grandchildren, Archie, Shay and Hugo
Contents
Introduction
Wildlife
We are all in this together
Humans are the cleverest species on Earth – or so we like to think. Although we are less than one million years on a planet that has had life of some sort for the last 3.5 billion years, we have been a most adaptable and successful species, according to our own standards that is. (I wonder what whales or pandas make of us or, indeed, what the dodo or the Tasmanian tiger might have to say if somehow, we could go back in time and interview them.) There are so many humans now that Earth is creaking at the seams. To keep going, we really need to know how the world works. It is not enough anymore to leave this to scientists and specialists.
After all, other species know how the world works and if they get it wrong, they don’t last. Survival of the fittest and all that. Hedgehogs that go for a second round of offspring because it has been a really good summer and there was lots of food available, find that 10the youngsters haven’t had enough time to put on the required kilogram of fat to tide them over the winter that inexorably follows. Birds that don’t build their nests in safe, hidden spots, well away from the beady eyes of always-watching magpies, may lose the whole clutch in a dawn raid. You’ve got to know what is going on.
Observing how the world works is fascinating. Nothing beats the evidence of your eyes and finding out explanations for it. But in a world where being fobbed off with a mad explanation on social media can have really significant impacts – as opposed to long ago when fake news meant believing that swans that go missing in summer have turned into beautiful maidens rather than migrated to tundra regions – it is more vital than ever that we all know exactly what is going on and how the natural processes work.
Our planet exists in harmony with the species that inhabit it. While the climate might have been changing over the millions of years, the species on it evolved and adapted to the changing conditions. It was only when a calamitous change happened that species extinction was the outcome. We know that this happened 65 million years ago when the planet was struck by a meteorite and the dinosaurs became extinct as their world had changed quicker than they could adapt to it.
The world is changing very quickly at the moment – according to its own terms of reference as it were. It is heating up exceedingly fast and climatic conditions are affected. This is being caused by one species – humans – who because of their huge numbers and their unsustainable exploitation of the Earth’s resources are changing the Earth’s atmosphere so that it traps and retains more of the sun’s heat. And this is happening in a very short period of time – less than a hundred years. It is calculated that there are less than ten years left 11at this rate before irreversible change occurs.
We have a beautiful world and we humans are behaving in a beastly way to it. Understanding what is going on is vital for everyone so that the steps needed to sort this out can be taken and supported. It doesn’t have to be a technical, scientific explanation – a humorous simple scientific explanation does the job too. We share our world – there are other ways of living. We do need to understand this. We are only one species and yet so often the attitude to an unrecognised fellow species and sharer of our world is ‘what is this and what will it do to me?’ or ‘what is this and how do I get rid of it?’ It’s not all about me actually – it’s all about us all. We are all in this together.
1
The Great Outdoors
How the world works
If we don’t know how the world works, how can we possibly know how to behave in it? By a series of amazing co-incidences, planet Earth is suitable for living things to exist on it. This is so remarkable that, as of yet, in all the galaxies in space that we have discovered, we have not found a single other place where we have detected living things. There are no other planets to which we can migrate when we have banjaxed this one. The mad money being spent travelling to outer space would be much better spent keeping this planet habitable for life here. Imagine the terror among living things on some other planet, if such an inhabited one is ever found by us, when they see us coming and learn what we did to our own beautiful Blue Planet.
Viewed from space, it is indeed a blue planet because two-thirds of its surface is covered with water. We are the only planet that we 13know, so far, that has water and the conditions suitable for retaining it. Water plays a vital role in maintaining life on Earth.
The way the world works is beautiful in its simplicity. It is heated by our star – the sun – from which we are just the right distance to get the right amount of warmth. Too near and, like Mercury and Venus, it would be far too hot. Too far away, like Mars, Jupiter and Saturn, and it would be everlastingly cold. But like in the fairy story about the greedy Goldilocks who wanted to gobble the porridge she found in the house of the three bears, the temperature of Baby Bear’s porridge (and our planet Earth) was just right. And believe it or not, this co-incidence that finds our planet getting just the right amount of heat to support life is called the Goldilocks effect.
Our atmosphere is just right too. First of all, we actually have one. It consists of gases in the right amounts – nitrogen, oxygen, carbon dioxide, water vapour and a few rare inert gases. The percentages of these have changed, albeit slowly, over the 4.5 billion years of the Earth’s existence. There is an equilibrium between life on Earth and the atmosphere around it. Or there was, that is, until one species – humans – got too big for its boots.
We have several broad categories of living things – plants, animals and microbial life, such as bacteria. The interaction between all these is what keeps the whole show on the road. The sun provides all the energy needed. Plants make all the food for the other two groups, using the energy in sunlight to fix carbon from the carbon dioxide in the air to make carbohydrates and from them other more complicated food groups. A by-product of this is oxygen, which the other two groups need to survive.
Animals depend on the plants for their food. Some eat the plants directly and rejoice in the swanky title of herbivores. Others kill 14and eat these herbivorous animals – these are the carnivores. And some very well-adapted animals can digest both the plants and the meat from animals and go by the accolade omnivores.
The third group – bacteria et al – are the decomposers. They break down dead plants and animals and release the carbon back into the atmosphere as carbon dioxide – ready for the plants to take it in as they grow. A very elegant and stable cycle indeed.
There are a few rules as it were. All the food is made by the plants and the energy it provides passes up through the food chain, diminishing as it goes. Herbivores don’t eat ALL the plants in a balanced world or they would quickly run out of food as there would be no seeds from which new plants could come. Carnivores don’t eat all the herbivores either. The rules of ecology say that the predator is controlled by its prey, not the other way round. The predator picks off the weak, the slow of foot, the unwary, but the smartest and best adapted survive – the survival of the fittest.
And no carnivore will expend more energy catching its prey than it gets from the kill when it finally makes it. While cheetahs can run faster than wildebeests, such fast running uses up a huge amount of energy. It cannot afford to chase the poor beast all day. It needs to sneak up carefully and then, with a final burst of speed, nab the unwary animal. If it misses, it doesn’t pursue the chase; it shrugs its shoulders, says ‘ah well’ (or something) and waits for another to come along. Hounds are only able to pursue a fox for a long time in the so-called sport of foxhunting if they are first well fed in the kennels. If the dead fox were their only sustenance, they couldn’t do it.
In good times, when it all works well, animals thrive, come into heat and reproduce. But there can’t be enough food for all the 15offspring to survive or else the numbers would increase exponentially. Imagine the two robins in your garden building their nest and being watched so fondly by yourself. Four eggs, four chicks, and in a half-good year, robins will nest twice. (In a really good year they might even nest three times, but let’s just go with twice.) So at the end of the summer, if the rules of ecology were suspended, you would have ten robins in your garden – Daddy and Mammy and eight babbies – five times the original number. And going with this scenario there would be ten robins in each robin territory in the parish. Robins can live for ten years. If they reproduce at the same rate, there will be 50 robins in your garden in a year’s time, and 250 the following year. By year ten the number is just short of 4 MILLION. But, actually, in year ten there are only two robins in your garden. And there is not a heap of almost 4 million dead robins piled up on the front lawn either. The truth is that for the population of robins to keep steady there must only be two robins the following spring to breed in your garden. One of the adults and one of the eight offspring will have survived, and no, they are not here in your garden breeding with each other, they have found new partners over the winter. Only the smartest youngster has survived. The others have become food for carnivores higher up the food chain or they have died of hunger, being unable to find food in the winter, as also happened to one of the original two adults. I am not making this up – bird ringing studies over the decades have provided chapter and verse.
And it is the same for all the species. A butterfly will lay 100 eggs on your prized cabbages. If one or two of them succeed in becoming a butterfly, the species is stable. The other 98 caterpillars will have gone to feed the baby robins. You can see how a food 16chain easily becomes a food web, as baby robins are fed other things too, such as spiders and small worms. And that is how it works. The availability of food controls the number of individuals that can survive. Animals of course have developed techniques over the ages to make sure to survive. Move away if all the food here is gone. Sleep if there is nothing to eat, and drop your metabolic rate so that you need less energy when times are very hard. Eat something else too; don’t just depend on one food. If you can’t do any of these, then indeed you might become aimsir caite, as happened to the giant Irish Deer. On the other hand, sharks are in such perfect equilibrium with their environment that some species haven’t altered at all in millions of years.
Humans began to evolve about three quarters of a million years ago. They are omnivores, and for most of the time since then, they were hunter-gatherers. Palaeolithic (Stone Age) people and Mesolithic people hunted animals and gathered plants, living in relative harmony with the earth, as indeed some forest tribes in tropical rainforests do to this day. Until ten thousand years ago we were all hunter-gatherers, and our whole world population was estimated to be around 10 million, give or take a few million.
And then we discovered farming. We could control the supply of our food. Someone – probably a woman – noticed that some of the grains that she had been painstakingly collecting and grinding into flour of sorts had not been ground up but abandoned somewhere and grew into fat little grasses with more of the same seeds. Get enough of these, plant them yourself and wait a season and then there wouldn’t be all this traipsing around gathering and moving on when all was collected, Why, she could build a nice permanent tent and send the children to school. Similarly, the young of the herds 17that the men spent so long away hunting, could be kept around the place and domesticated. And the men would then be there to help with everything. Yes, in theory, it was a great idea.
Farming began in the Fertile Crescent around the Euphrates River in the Middle East about ten thousand years ago and humans felt that they were sorted. All you needed was land to farm. They increased and multiplied because they could grow enough food for all, and they began to spread out seriously. As the last Ice Age retreated, lands in Europe became available. The first farmers – Neolithic people – to arrive in Ireland made it here 5,000 years ago and we have evidence of their first fields and what they farmed, in the Céide Fields of north Mayo.
Meanwhile, the rest of the species on Earth behaved as they always did. Which is just as well, as life on Earth is only possible with the co-operation of all the species here. Let’s look in more detail at what is involved and the interesting ways our fellow species live.
2
Pollination
Another name for the birds and the bees actually
I have a friend who a few years ago got himself a polytunnel. He was delighted with it. At last, he could grow the things that it was always too cold or too windy to grow outdoors. Strawberries were high on his list. His outdoor attempts before this had always been gobbled by slugs before they even ripened, or else the blackbirds finished off the rest. Now with his polytunnel, such marauders would be kept at bay. And, indeed, his strawberry plants grew very well and had lots of flowers in early May. Things were looking good. But he didn’t get one single strawberry fruit on any of the plants. I was duly called in to advise. His polytunnel was nice and hot; he had watered everything with due diligence; it was in a bright spot in the garden so there was plenty of light. Did he leave the two ends open each day, I asked him? Of course not, he didn’t want birds flying through gobbling his strawberries or slugs slithering in 19either. So, nothing flew in at all. How did he think his strawberry flowers were going to be pollinated if he kept all the flying insects out? No insects, no pollination, no strawberries. Time for a chat about the facts of life.
Why do plants have flowers anyway? The answer is that this is where their reproductive parts are. Many flowers have both male and female parts in the one flower. The male parts are the stamens and at the top of each stamen the pollen is stored. The female part is in the centre of the flower and is called the ovary. A long tube called the style – there can be more than one – leads down to the ovary. And, indeed, some flowers may have more than one ovary. But the basic fundamental principle is the same whatever the individual arrangement is. The male pollen must go into the female ovary and fertilise it before seeds can form. Naturally, in the interest of genetic variation, flowers don’t pollinate themselves. (There are of course exceptions, but in general this is the case.) So, to avoid mischance, the pollen and ovary in any particular flower are not ripe at the same time. Pollen must come from another flower and land on the receptive stigma at the top of the style in order to fertilise the flower.
But pollen cannot move by itself. Something has to bring it. And at our latitudes this is done by insects – pollinating insects or pollinators. In tropical countries some pollination is carried out by birds, such as hummingbirds, or by fruit bats, but here we are dependent on our pollinating insects. Why should our insects pollinate our flowers? What is in it for them? Like any good trade union member, they are not going to work without pay. But actually, they don’t have a meeting every morning and say we must go out and do our good deed for the day and pollinate plants. If they have meetings at 20all, they decide to go out to the pub for a pint. Because that is why most insects visit flowers – for the free drink that is nectar.
Flowers have evolved together with insects and they depend on each other. The lovely petals and the smells produced by the flowers are to attract the pollinating insects. The pay for the job is a drink of lovely sweet nectar. But flowers are no fools. They keep their nectar well hidden, deep down in the flower, and the visiting insect has to stick its head right in, in order to suck up the lovely liquid. But in truth it is not much of a pub. There is only one small drink on offer and so the still-thirsty insect has to go on a pub crawl, as it were, of many flowers to get enough nectar. As it goes down deep into the flower, it rubs its hairy head off the ripe pollen which stays on it as it flies off to the next flower. Here, it might be the female ovary that is ripe, and the nectar-seeking insect accidentally deposits the pollen from the last flower on the sticky stigma as it quests for more nice nectar. And BINGO, fertilisation happens.
The insect doesn’t care; all it wants is the nectar. The head covered in pollen is an awkward side effect as far as it is concerned. And this is the story with all the butterflies, hoverflies, wasps, and other flies that visit flowers. They are only after the one thing … nectar.
The only group of insects that actually wants pollen is the bees. It is a nuisance to everyone else. But bees collect pollen because it is rich in protein and they bring it back home to feed the baby bees in their larval state. The bees have modified hairs on their back legs – pollen baskets – which they load up with pollen collected from the flowers they visit. They too have to visit lots of flowers to collect a full load, and as they do, they carry some from one flower to another and fertilisation takes place. A loaded honeybee can carry up to a third of its weight in pollen back to the hive – the equivalent 21of a human with 30kg of luggage. They spend three weeks of their life collecting pollen to feed the young and then they switch tasks to collecting nectar to bring home to make honey – the food of the adult bees. Again, this requires the head to be inserted deep into the flower and the nectar sucked up into the bee’s nectar sac. To fill the sac, several flowers have to be visited and of course pollen adhering to the hairy head of the bee will be transported and deposited as she does this. In this way bees do twice as much pollinating as the other groups of insects. No wonder she drops dead of exhaustion after six weeks’ work – three on pollen-collecting duty and three on nectar collection. Being as busy as a bee is not necessarily a good way to be described if you are a human!
My friend’s polytunnel was never visited by any flying insect and so no pollination of his strawberry flowers ever took place and therefore he had no strawberries. (But the carrots and the lettuce and scallions did well, so I didn’t leave empty-handed.)
Some very sophisticated flowers have evolved to be pollinated by the birds, not by the bees. Well, not any old bird species, but by birds that depend on them for nectar, as they have no other source of food. The hummingbirds of North America are a wonderful example of this. Why are they called hummingbirds? Have they forgotten the words of the song and have to hum the tune instead? Well no, actually. The humming sound comes from the very fast movement of their wings – up to fifty beats per second – as they hover in front of an attractive flower.
