My Science School

Terrestrial ecosystems are many because there are so many different sorts of places on Earth. Some of the most common terrestrial ecosystems that are found are the following:

Rainforests – Rainforests usually have extremely dense ecosystems because there are so many different types of animals all living in a very small area.

Tundra – As mentioned above, tundra usually have relatively simple ecosystems because of the limited amount of life that can be supported in these harsh conditions.

Deserts – Quite the opposite of tundra in many ways, but still harsh, more animals live in the extreme heat than live in the extreme cold of Antarctica, for instance.

Savannas – These differ from deserts because of the amount of rain that they get each year. Whereas deserts get only a tiny amount of precipitation every tea, savannas tend to be a bit wetter which is better for supporting more life.

Forests – There are many different types of forests all over the world including deciduous forests and coniferous forests. These can support a lot of life and can have very complex ecosystems.

Grasslands – Grasslands support a wide variety of life and can have very complex and involved ecosystems.

Since there are so many different types of terrestrial ecosystems, it can be difficult to make generalizations that cover them all.

Because terrestrial ecosystems are so diverse, it is difficult to make generalizations about them. However, a few things are true almost all of the time. For instance, most contain herbivores that eat plants (that get their sustenance from the sun and the soil) and all have carnivores that eat herbivores and other carnivores. Some places, such the poles, contain mainly carnivores because not plant life grows. A lot of animals and plants that grow and live in terrestrial ecosystems also interact with freshwater and sometimes even ocean ecosystems.

The map below shows the main ways in which the Earth can be divided into different ecosystems. These are based mainly on the kind of plants that grow in an area, as all other living things rely directly or indirectly on plants for their food. Of course, there are many smaller ecosystems within these broad divisions.

An ecosystem consists of all the living and non-living things in a specific natural setting. Plants, animals, insects, microorganisms, rocks, soil, water and sunlight are major components of many ecosystems. All types of ecosystems fall into one of two categories: terrestrial or aquatic. Terrestrial ecosystems are land-based, while aquatic are water-based. The major types of ecosystems are forests, grasslands, deserts, tundra, freshwater and marine. The word “biome” may also be used to describe terrestrial ecosystems which extend across a large geographic area, such as tundra. Keep in mind, however, that within any ecosystem, specific features vary widely – for instance, an oceanic ecosystem in the Caribbean Sea will contain vastly different species than an oceanic ecosystem in the Gulf of Alaska.

Forest Ecosystems

Forest ecosystems are classified according to their climate type as tropical, temperate or boreal. In the tropics, rainforest ecosystems contain more diverse flora and fauna than ecosystems in any other region on earth. In these warm, moisture-laden environments, trees grow tall and foliage is lush and dense, with species inhabiting the forest floor all the way up to the canopy. In temperate zones, forest ecosystems may be deciduous, coniferous or oftentimes a mixture of both, in which some trees shed their leaves each fall, while others remain evergreen year-round. In the far north, just south of the Arctic, boreal forests – also known as taiga – feature abundant coniferous trees.

Grassland Ecosystems

Different types of grassland ecosystems can be found in prairies, savannas and steppes. Grassland ecosystems are typically found in tropical or temperate regions, although they can exist in colder areas as well, as is the case with the well-known Siberian steppe. Grasslands share the common climactic characteristic of semi-aridity. Trees are sparse or nonexistent, but flowers may be interspersed with the grasses. Grasslands provide an ideal environment for grazing animals.

Desert Ecosystems

The common defining feature among desert ecosystems is low precipitation, generally less than 25 centimeters, or 10 inches, per year. Not all deserts are hot – desert ecosystems can exist from the tropics to the arctic, but regardless of latitude, deserts are often windy. Some deserts contain sand dunes, while others feature mostly rock. Vegetation is sparse or nonexistent, and any animal species, such as insects, reptiles and birds, must be highly adapted to the dry conditions.

Tundra Ecosystems

As with deserts, a harsh environment characterizes ecosystems in the tundra. In the snow-covered, windswept, treeless tundra, the soil may be frozen year-round, a condition known as permafrost. During the brief spring and summer, snows melt, producing shallow ponds which attract migrating waterfowl. Lichens and small flowers may become visible during this time of year. The term “tundra” most commonly denotes polar areas, but at lower latitudes, tundra-like communities known as alpine tundra may be found at high elevations.

Freshwater Ecosystems

Freshwater ecosystems can be found in streams, rivers, springs, ponds, lakes, bogs and freshwater swamps. They are subdivided into two classes: those in which the water is nearly stationary, such as ponds, and those in which the water flows, such as creeks. Freshwater ecosystems are home to more than just fish: algae, plankton, insects, amphibians and underwater plants also inhabit them.

Marine Ecosystems

Marine ecosystems differ from freshwater ecosystems in that they contain saltwater, which usually supports different types of species than does freshwater. Marine ecosystems are the most abundant types of ecosystems in the word. They encompass not only the ocean floor and surface but also tidal zones, estuaries, salt marshes and saltwater swamps, mangroves and coral reefs.

          Over time, ecosystems can alter a great deal. The climate of the Earth has gradually changed many times even within the time when records have been kept. Before that we know that parts of the world experienced Ice Ages, which had huge effects on the environments of living things. Human beings also alter ecosystems, often without realizing the possible results of their actions. Once large areas of North America and Europe were covered with deciduous woodland. Over hundreds of years, trees have been cut down for building, to supply fuel and to clear land for farming, so that remaining areas of woodland are comparatively small.

          Whether just starting out or full of life, ecosystems are constantly changing. The process in which they are changing is called succession. Succession comes in two forms: primary and secondary. Primary succession is “the series of community changes which occur on an entirely new habitat which has never been colonized before.” These changes occur in places like area of cooled down lava, sandy areas and chiseled out rock faces.

          Secondary succession is “the series of community changes which take place on a previously colonized, but disturbed or damaged habitat.” These places involve areas damaged by fires, floods, or areas where the trees have been cut down. These disturbances have not taken away all forms of life and nutrients from the area. If succession is done in a proper way, the ecosystem can become a climax community in which the ecosystem stabilizes. The process in becoming a climax community can take either a short or long time which differs from area to area. There can also be times which it is set back a few stages, like when trees are cut down. This sets the area back some, but it can still grow back and still become a climax community. The climax is stabilized by a small community of prominent species. The web of biotic interaction that a climax community creates is so intimate that an introduction of a new species could disrupt the stabilization. If a new species were to be introduced, it could cause one species to become too dominant. However, this ecosystem would be more diverse. This loss of stabilization could easily be called a disturbance.

           A disturbance is a mixture of large, infrequent and small frequent events and they can occur from the result of numerous, interconnected factors. Disturbances are categorized by type, severity, intensity, frequency, and timing. The word disturbance makes it seem like it has a negative effect on ecosystems, but the opposite is true. For example, most natural disturbances help renew ecosystems and diversify the landscapes. As stated earlier, they often lead to ecological succession. However, anthropogenic disturbances, ones related to humans, often have negative effects. For example, if humans introduce invasive species into the environment, they can hunt and prey on native species and disrupt the ecosystem’s stability.

         Within each type of succession is a stage. These stages include pioneer, establishing, sustaining, and producing. Each of these are found in the types of succession, but are not necessarily in only one. The pioneer stage is usually in primary succession. This stage brings new life to area where there is none. It is and creature or plant that starts to grow or live there. It is the start of the ecosystem. This next stage is very similar to the pioneer stage. The establishing stage is when animals or plants find things that sustain their lives and allows them to live in the area. The sustaining stage is usually in the climax succession. It is when the area can sustain life and allows life to continue in the area. The animals also do not have to leave in order to find food. The other stage is the producing stage. This is usually during the secondary succession. It happens when the population of animals is growing but many drift to other places in search for food. These places can sustain life but at a limited population. These types of succession, the stages and the disturbances that cause them all create and change and ecosystem though the years.

          Different parts of the world vary enormously in the kinds of plant and animal life they can support. This is mainly caused by the climate in each place, which allows different kinds of living things to thrive. The climate itself is influenced by the physical characteristics of a region —whether it is mountainous or near the sea, for example —and its position on the Earth — how near to the equator it is. Different parts of the world can share similar conditions, even if they are thousands of miles apart. Each area contains communities of millions of living things that rely on each other for survival. These communities are called ecosystems.

          An ecosystem includes all of the living things (plants, animals and organisms) in a given area, interacting with each other, and also with their non-living environments (weather, earth, sun, soil, climate, atmosphere). Ecosystems are the foundations of the Biosphere and they determine the health of the entire earth system. Consider a small puddle at the back of your home. In it, you may find all sorts of living things, from microorganisms to insects and plants. These may depend on non-living things like water, sunlight, turbulence in the puddle, temperature, atmospheric pressure and even nutrients in the water for life.

          This very complex, wonderful interaction of living things and their environment has been the foundations of energy flow and recycle of carbon and nitrogen. Anytime a ‘stranger’ (living thing(s) or external factor such as rise in temperature) is introduced to an ecosystem, it can be disastrous to that ecosystem. This is because the new organism (or factor) can distort the natural balance of the interaction and potentially harm or destroy the ecosystem. 

          Usually, biotic members of an ecosystem, together with their abiotic factors depend on each other. This means the absence of one member or one abiotic factor can affect all parties of the ecosystem.

          Unfortunately, ecosystems have been disrupted, and even destroyed by natural disasters such as fires, floods, storms and volcanic eruptions. Human activities have also contributed to the disturbance of many ecosystems and biomes.

          The concept of the ecosystem has evolved since its origin. The term, coined in the 1930s, belongs to British botanists Roy Clapham (1904-1990) and Sir Arthur Tansley (1871-1955). It was originally applied to units of diverse spatial scale; from a weathered piece of tree trunk to a pond, a region or even the entire biosphere of the planet, the only requirement being that organisms, physical environment and interactions could exist within them.  

          This is the extremely vital life-support services ecosystems provide to human life, its well-being and future economic and social development. For example: The benefits ecosystems provide include food, water, timber, air purification, soil formation and pollination.

Bushfires happen almost every year across the island-nation of Australia. However, this time around, it has been one of the worst-ever. What began in September 2019 has continued well into 2020. It has claimed more than 25 lives while reducing millions of acres to ash. And New South Wales was hit the hardest – in this State alone, more than half-a-billion creatures, including mammals, birds and reptiles, are feared to have perished. There are reports that thousands of kangaroos and koalas have been consumed by the fire across the country. The last few decades have seen an increase in the number of bushfires, and may be attributed to global warming. As for Australia, the bushfires season seems to be beginning earlier and lasting longer. In a chilling revelation, the U.K. scientists have said that the recent fires in Australia are assign of what the world will go through as temperatures increase.

 

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A telling identity of our planet’s biodiversity, the tiger is also a keystone species. And its population the world over, and especially in India, has been of particular concern. However, July 2019 brought with it some comforting news. The findings of the Tiger census, conducted in our country once in every four years, showed that the tiger population had increased from 2,226 in 2014 to 2,967 in 2018. With that, India is estimated to be home to around 70% of the world’s tigers. Following an alarming decrease in the tiger population since the early 20th Century, the government had put in place stringent laws in the 1970s to protect the national animals, and this seems to have been paying off over the last decade or two. However, human-animal conflicts continue, and conservationists have repeatedly called for an increase in protected areas for the tiger.

 

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Between September and October 2018, the Gir forest sanctuary – the only place to find the Asiatic lion in the wild today – lost nearly 25 of its most popular inhabitants. The death of lions is believed to have been caused by a potent combination of canine distemper virus and babesiosis, a disease caused by tick-borne parasites, according to government officials. The officials also said that the lions belonged to one pride. Following the deaths, 33 lions from the area were rescued, quarantined and vaccinated and kept under observation. Interestingly, answering a question at the legislative Assembly in early 2019, the Gujarat government said that over 200 lions had died in the Gir forest region in the previous two years (2017 and 2018).

Canine Distemper is a viral disease that is frequent in dogs, foxes, wolves, big cats and even primates. It is caused by a single-stranded RNA virus of the family Paramyxoviridae (the family of viruses causing measles, mumps and bronchiolitis in humans). It infects the spinal cord and brain and also the respiratory and gastrointestinal tracts. The virus is believed to have a 50% fatality rate in dogs.

In 1994, the CDV was responsible for an epidemic in the Serengeti region of Africa, where 1,000 lions died in three weeks. Its prevalence in India has not been studied and only a few reports are available regarding its detection in wild carnivores.

 

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It’s not Al Gore. It’s not DiCaprio. It’s a teenager that’s undeniably the face of the environment chapter in the book of impactful stories from the decade. Swede Greta Thunberg’s story begins on August 20, 2018, when the 15-year-old skips school to protest outside parliament for more action against climate change, with just a placard in hand. Within a week, she is joined by students, teachers, parents, and has the attention of the media. Soon enough, she marks Fridays for climate protest, and suggests students everywhere take up the “Fridays of Future” campaign by staging walkouts at their own schools. How she made an entire world hear her out is history. When a few world leaders undermined her concerns, determination and impact, she came up with witty updates on her social media pages, showing them – and us – that she’s more than just a concerned teenager asking irresponsible adults “How Dare You?”

 

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The U.S. suffered three hurricanes – Hurricane Harvey, Irma and Maria in just two months, August and September 2017. It would also turn out to be among the five costliest-ever to hit the country. The National Oceanic and Atmospheric Administration announced that together they cost the country USD 265 billion. The storms brought widespread death and destruction to Texas, Florida, Puerto Rico and the U.S. Virgin Islands. Since the hurricanes killed hundreds of people and brought misery and hardship to millions of people and brought misery and hardship to millions of Americans, the World Meteorological Organization decided to retire the names of these hurricanes.

NOAA said the dollar amounts are "the estimated total costs of these events — that is, the costs in terms of dollars that would not have been incurred had the event not taken place. Insured and uninsured losses are included in damage estimates." 

In all, 2017's hurricanes caused more than a quarter-trillion dollars in insured and uninsured losses, the National Hurricane Center reported. 

 

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On June 1, 2017 the U.S. President Donald Trump announced his decision to pull out of the Paris Agreement that his predecessor had signed. The agreement had come into force on November 4, 2016. Trump claimed it “gives undue advantage to India and China at the cost of the United States’ interests”, and that it “is less about the climate and more about other countries gaining a financial advantage over the U.S.”. He also insisted that the accord would have negative impacts on job growth, manufacturing and industries. His speech suggested that he was open to negotiations to “make a deal that’s fair”.

To date there are only two other countries that have not yet signed on to the Paris Agreement: Syria and Nicaragua. Syria, which remains in the throes of a destructive civil war, noted that it was not in a position to sign such agreements because of ongoing sanctions from Western countries. The government of Nicaragua, however, refused to sign on for different reasons. Nicaragua believes that the Paris Agreement does not go far enough to reduce emissions, arguing that wealthy countries such as the United States should have been forced to make deeper commitments.

 

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In October 2016, a vast stretch of ocean off Antarctica received international protection to become the world’s largest marine reserve. Over 15 lakh sq.km of water in Ross Sea is protected, thanks to the decision of the international body that oversees the waters around Antarctica- the Commission for the Conversation of Antarctica Marine Living Resources, comprising 24 countries. The nutrient-rich waters of the region are the most productive in the Antarctic, and the protection will guard everything from krills to penguins and whales. Unfortunately, only two years later, Russia, Norway and China would stop global efforts to turn a huge tract of pristine Antarctic Ocean into the world’s biggest sanctuary of about 1.8 million sq.km.

 

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Due to higher-than-normal water temperatures in 2015 and 2016, Australia’s Great Barrier Reef suffered its worst-ever coral bleaching event on record. According to a November report by researchers at ARC Centre of Excellence for Coral Reef Studies in James Cook University, about 67% coral had died in the worst-hit northern part. However, those in the southern part were in good health, while the central part of the Reef witnessed a six % die-off, the report said. Since coral bleaching (or die-off) usually occurred as a result of continuous warm water temperatures, scientists were concerned about the recovery of the corals.



The Great Barrier Reef is made by trillions of tiny invertebrate creatures known as coral polyps, which have built it over the past 600,000 years. The polyps, which excrete calcium carbonate to make reefs, are extraordinarily sensitive to changes in water temperature. When it rises by two to three degrees Celsius above normal levels many species of coral are forced to expel the multicoloured algae that live within its tissues, an effect known as “bleaching”.  The white coral skeletons that remain can regenerate if temperatures fall and water quality conditions are good. But in many instances entire reef systems can be destroyed if water temperatures remain elevated for several months. 

 

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June 2015 was a terrible month to be a human. Anew study in the journal “Scientists confirmed what only the discerning had perhaps expected all along – that the sixth global mass extinction was happening and humanity’s existence was being threatened. The researches had used conservative estimates to prove that “species are disappearing faster than at any time since the dinosaurs’ demise”. We are wiping species off our planet at a rate at least 100 times faster than historical levels. They called for swift action to conserve threatened species, populations and habits, and also cautioned that the window of opportunity was closing really fast.

The impacts of a still-avoidable sixth mass extinction would likely be so massive they’d be best described as science fiction. It would be catastrophic, widespread and, of course, irreversible. In the past, it has taken life ten to thirty million years to recover after such an extinction, 40 to 120 times as long as modern-looking humans have been telling tales by firelight. Moreover, Williams and his team argue that future changes driven by humanity may go so far as to create not just a new epoch in geologic history – such as the widely-touted Anthropocene – but a fundamental reshaping of Earth on par with the rise of microbes or the later shift from microbes to multicellular organisms.

 

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Also known as Paris Climate Accord, this historic and landmark climate pact was forged in Paris in December 2015, under the United Nations Framework Convention on Climate Change (an international environmental treaty). Nearly all the countries of the world adopted it. Considered the world’s first comprehensive climate agreement, it focuses primarily on bringing down increasing global temperatures by at least two degrees Celsius over pre-industrial times; reducing the amount of global emissions; and strengthening the abilities of countries to deal with climate change. With the signing of the Agreement, the then U.S. President Obama is believed to have hoped for “a world that is safer and more secure, more prosperous, and more free”. However, his successor would soon pull the rug out from under the world’s feet.

 

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December 2014 turned out to be a horrific end to the year for Sundarbans, the largest contiguous tidal mangrove forest in the world. On the morning of December 9, a tanker carrying furnace oil and a cargo vessel collided in Sundarban’s Shela river, the former sinking and spilling over 3.5 lakh litres of oil into a region popular for its rich biodiversity, including the endangered Irrawaddy dolphin, the Ganges river dolphin and the royal Bengal tiger. Within days, the impact of the toxic oil spill was visible – oil-coated marine creatures (dead or barley surviving) and sharp drop in the diversity of phytoplanktons and zooplanktons, among other signs. Thus, however, would not be the last disaster this region would witness – a ship with fertilizer and two vessels with coal would all sink in the next few years because of shipping bans being withdrawn as quickly as they are imposed.

 

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