The Grassland Biome - Biomes #5

Summary

This script explores the global dominance of grasses, which have adapted to nearly every environment except ice sheets. Grasslands, characterized by grasses and scarce trees, are found in temperate, dry climates and high altitudes. The script distinguishes grasslands from tropical savannahs and describes regional variations like prairies, steppes, pampas, and veldt. It highlights the ecological importance of grasslands, their role in supporting grazing animals like bison, and the transformation of many natural grasslands into agricultural lands, particularly for cereal crops, which are also grasses. The script concludes by emphasizing the grass family's significance to human civilization and the environment.

Takeaways

• 🌿 Grass is the most widespread plant on Earth, found in every biome except ice sheets.
• 🌱 Humans have cultivated grasses into staple crops like wheat, corn, and rice, which are essential for global food supply.
• 🌍 Grasslands are unique biomes dominated by a single class of plants, with over 12,000 species of grass.
• 🔥 Grasses have evolved to thrive in poor soils, withstand fire, and outcompete other plants, allowing them to spread widely.
• 🌾 Prairies and steppes are examples of grassland biomes where grasses are the dominant vegetation.
• 🌤️ Grasslands are typically found in temperate, drier climates with insufficient rainfall for tree growth or where historical conditions prevent tree establishment.
• 🌍 The terms 'Prairie', 'Steppe', 'Pampas', and 'Veldt' are regional descriptors for grasslands around the world.
• 🌱 Grass height varies with rainfall and soil conditions, with taller grasses in wetter soils and shorter grasses in arid conditions.
• 🌼 Grasslands burst into color during the spring or wet season, marking the time for plant reproduction.
• 🌱 The domestication of grasses into cereal crops has been a pivotal development in human civilization, feeding billions worldwide.

Q & A

What is the most dominant plant on Earth?

Grass is the most dominant plant on Earth, occupying every biome except the ice sheets.

How have humans shaped grasses over generations?

Humans have shaped grasses over generations into crops that feed the world today.

What are the defining characteristics of grass?

Grass is a non-woody plant with a hollow stem for strength, bladed leaves for photosynthesis, and a flowering bundled seed head for reproduction.

How long has grass been evolving, and how many species exist today?

Grass has been evolving since the end of the Cretaceous period, about 66 million years ago, and there are over 12,000 species today.

What are the two biomes on Earth completely dominated by a single class of plant?

Grasslands are one of the two biomes on Earth completely dominated by a single class of plant, grass.

What are the typical climate conditions for grasslands?

Grasslands typically occur in relatively temperate, drier climates, either in mid-latitudes or high-altitude regions where rainfall is insufficient for tree growth.

What is the difference between grasslands and savannahs?

Grasslands are dominated by grasses, while savannahs are a mix of grasses, shrubs, and trees.

What are some regional terms used to describe grasslands?

Prairie is used for grasslands in North America, steppe for those in Eurasia, pampas for the grasslands of mid-southern South America, and veldt for the open upland country of eastern South Africa.

How does the height of grass in grasslands vary?

The height of grass in grasslands is determined by the amount of rainfall and soil drainage; wetter soils support taller grass, while arid conditions lead to shorter grass.

Where are the largest areas of grasslands found?

The largest areas of grasslands are found in the great plains of North America and Eurasia, which include prairies and steppes.

What has happened to most of the natural grasslands due to human activity?

Most of the natural grasslands have been replaced by agriculture due to the quality of their soils and suitability for cereal crops.

How have grasslands contributed to human civilization?

The domestication of various grass species into cereal crops is regarded as one of the key developments of human civilization, as many of our staple foods are grasses.

Outlines

00:00

🌿 Grassland Dominance and Characteristics

This paragraph introduces grass as the dominant plant species on Earth, excluding ice sheets, and its ability to adapt to various biomes. Grasses have been cultivated by humans into crops that sustain the world's food supply. The paragraph explains the definition of grass, its evolution since the end of the Cretaceous period, and its unique ability to colonize poor soils and outcompete other plants. It distinguishes grasslands from savannahs and describes the climatic conditions that favor grassland formation. The paragraph also discusses the regional terms for grasslands, such as prairie, steppe, pampas, and veldt, and the technical variations in grass height and root systems based on rainfall and soil conditions. The importance of grasslands in supporting grazing animals and the transformation of natural grasslands into agricultural lands for cereal crops are also highlighted.

05:02

🌍 Global Distribution and Types of Grasslands

This paragraph delves into the geographical distribution of grasslands, focusing on North America and Eurasia as the primary regions where grasslands are found. It describes the North American prairies, their transition from tallgrass prairies in the east to semi-arid conditions in the west, and the impact of agriculture on the preservation of natural prairie. The paragraph also covers South American grasslands, including the Puna, Pampas, and the grasslands of southern Patagonia and the Falkland Islands. It mentions the small but significant grasslands in eastern South Africa known as the Veldt and the surprising presence of grasslands in New Zealand due to poor soils and rain shadow effects. The paragraph further discusses the grasslands in the Middle East and around the Tibetan plateau, emphasizing the vast Eurasian Steppe as the largest grassland area on Earth. It concludes with a discussion on the species diversity in natural grasslands and the historical significance of grasslands in supporting large herds of grazing animals and the evolution of key species like the horse.

10:06

🌱 The Impact of Human Activity on Grasslands

This final paragraph reflects on the impact of human activity on grasslands, noting the conversion of natural grasslands into agricultural lands for cereal crops. It acknowledges the irony that while grasslands have been diminished, they have been replaced by domesticated grasses in the form of crops. The paragraph emphasizes the importance of grasses in human civilization as a key development, providing food directly and indirectly through livestock. It concludes with a call to action for viewers to engage with the content by liking, sharing, and commenting, and teases the upcoming episode on temperate forests.

Keywords

💡Grass

Grass is a non-woody plant with a hollow stem for strength, bladed leaves for photosynthesis, and a flowering seed head for reproduction. It is the dominant plant in grasslands, which are one of the few biomes dominated by a single class of plant. Grasses have evolved to colonize poor soils, survive fire, and outcompete other plants, allowing them to spread across various environments. In the video, grass is highlighted as a plant that has shaped human civilization by being domesticated into cereal crops, thus playing a crucial role in feeding the world.

💡Biome

A biome is a large community of plants and animals that occupies a distinct region defined by its climate, geography, and the types of life it supports. The video discusses grasslands as a biome, which is characterized by its dominance of grass species and occurs in various climates, from temperate to arid regions. Grasslands are contrasted with other biomes like tropical forests and savannahs, emphasizing their unique ecological role and the grass's adaptability.

💡Grassland

Grasslands are ecosystems where grasses are the dominant vegetation, covering vast areas and supporting a diverse array of wildlife. The video explains that grasslands are found in temperate, drier climates, and high-altitude regions where trees struggle to grow. Grasslands are further categorized into different types such as prairies, steppes, pampas, and veldt, each with distinct regional characteristics and grass species.

💡Prairie

Prairie refers to the grasslands of North America, a term borrowed from early French settlers meaning 'meadow'. The video describes the North American prairies as vast plains extending from Canada to the central USA, with the eastern parts being tallgrass prairies due to higher rainfall. The prairie ecosystem is a significant example of a grassland biome, showcasing the adaptability of grass species to different environmental conditions.

💡Steppe

Steppe is a term used primarily for the grasslands of Eurasia, derived from the Russian word for this biome. The video outlines the vast steppe plains of Eurasia, which run in an unbroken line at around 45°N latitude, separating the temperate and boreal forests of the north from the deserts of the south. The steppe is highlighted as an example of a grassland biome with a significant impact on human history and agriculture.

💡Pampas

Pampas refers to the extensive grasslands of mid-southern South America, a term from the Quechua word for plain. The video notes that the Pampas have been largely converted to farming and ranching, illustrating the human impact on grassland biomes and the transformation of these ecosystems for agricultural purposes.

💡Veldt

Veldt is an Afrikaans word for field, used to describe the open upland country of eastern South Africa, which can be grassland or scrub. The video mentions the Veldt as a region where grasslands are found, albeit in a more limited and varied form compared to other grassland biomes, highlighting the diversity within the grassland category.

💡Tussock Grasslands

Tussock grasslands are found in New Zealand, resulting from poor soils in the North Island and a rain shadow in the South Island that reduces rainfall. The video uses the term to illustrate how grasslands can form in unexpected places due to specific environmental conditions, such as the unique climate and soil of New Zealand.

💡Cereal Crops

Cereal crops are grass species that have been domesticated for human consumption, including wheat, corn, rice, and barley. The video emphasizes the importance of cereal crops as a key development in human civilization, noting that these crops have replaced much of the natural grasslands, thus transforming the landscape while still maintaining the grass's role in feeding the world.

💡Horse

The horse is mentioned as an animal that evolved in the grasslands of North America and Eurasia, and it is considered one of the most important animals in human history. The video highlights the horse as an example of how grassland ecosystems have influenced human culture and development, from transportation to agriculture.

Highlights

Grasses dominate every biome on Earth except ice sheets, occupying a wide range of environments from tropical to desert.

Humans have shaped grasses into crops that are fundamental to global food supply.

Grasslands are one of only two biomes where a single class of plant, grasses, is completely dominant.

Grasses are non-woody plants with hollow stems, bladed leaves, and flowering seed heads, evolving since the end of the Cretaceous period.

Grasses' ability to colonize poor soils, survive fire, and outcompete other plants has allowed them to spread extensively.

Prairies and steppes are where grasses are fully dominant, contrasting with the mixed vegetation of tropical savannahs.

Grasslands occur in temperate, drier climates, often in mid-latitudes or high-altitude regions where trees struggle to grow.

The Koppen climate classification does not have a single type that matches global grassland distribution, indicating a varied climate tolerance.

Grasslands are found in the 'steppe' category on the Holdridge Lifezones chart, indicating a preference for drier conditions.

Regional terms like Prairie, Steppe, Pampas, and Veldt describe grasslands, each with unique geographical and cultural significance.

Grass height in grasslands is technically variable and influenced by rainfall and soil drainage.

Grasses have deep root systems that bind well to the soil, with some species having roots as deep as their above-ground structures.

Meadows burst into color during the plant reproduction season, which varies by latitude and climate.

The North American and Eurasian continents have the largest land areas of grasslands, with the Great Plains being a notable example.

South America has distinct grassland areas like the Puna, Pampas, and the grasslands of southern Patagonia.

Africa's eastern highlands host true grassland biomes known as the Veldt, distinct from the continent's tropical savannahs.

New Zealand's tussock grasslands are a surprising find, given the country's otherwise forested and oceanic climate.

The Eurasian Steppe is the largest area of grassland on Earth, stretching from Eastern Europe to Mongolia.

Grassland species diversity is high, with distinct species like Big bluestem in North America and Stipa in Eurasia.

Grasslands have supported vast herds of grazing animals, such as the tens of millions of Bison that once roamed North America.

The domestication of grass species into cereal crops is a key development in human civilization, with grasses now feeding the world.

Despite the conversion of natural grasslands to agriculture, grasses remain a dominant plant form in human-managed landscapes.

Transcripts

Grass.

If there is one plant that has come to dominate our world, it’s this.

Occupying every biome on earth except the icesheets, grasses have colonised every patch

of soil, from tropical to temperate forests, savannah to steppe, scrubland to desert.

Humans have taken these grasses and shaped them over generations into crops that feed

the world today.

Their homelands are the seas of grass we call Meadow, Prairie, Pampas, Veldt and Steppe

- the world’s Grasslands.

Grasslands are one of only two biomes on our planet to be completely dominated by a single

class of plant.

But what is grass?

A simple definition is a non-woody plant containing a hollow stem for strength, bladed leaves

for photosynthesis and a flowering bundled seed head for reproduction.

This simple but highly successful formula has evolved since the end of the Cretaceous

period, about 66 million years ago, to form over 12,000 species today, and grass’s ability

to colonise poor soils, survive fire, and turf out competing plants has allowed them

to spread to almost every corner of earth.

The prairies and steppes are the biomes where this class of plant is fully dominant.

This is in comparison to the Savannahs of the tropics, so often confused with grasslands,

where we find a mix of grasses, shrubs and trees.

Grassland areas occur in relatively temperate drier climates, either in the mid-latitudes,

or in high-altitude regions such as the Himalayas and Andes, where rainfall is insufficient

for tree growth, or where historical conditions, such as pervasive fire or large animal grazing,

have prevented trees from gaining a foothold.

There is no one Koppen climate type that matches the global grassland distribution, with continental

and cool semi-arid zones, along with humid and highland subtropical zones and even oceanic

areas having grasslands.

This indicates that the coupling between grassland and climate is not as strong as in the other

biomes so far looked at, with major Koppen groups B, C and D being represented here.

If we consult our Holdridge Lifezones chart, we can find the grasslands in the centre as

“steppe”, where conditions are neither particularly cold or hot, but where overall

rainfall is on the drier side, indicating that grasslands can dominate in these more

arid areas where trees might struggle.

So you’ve probably heard the terms Prairie and Steppe, and possibly Pampas and Veldt too.

These terms are more regional in usage than technical.

Prairie is almost exclusively used to refer to the grasslands of North America, and is

a word borrowed from the early French settlers to this region, meaning simply “meadow”

in that language.

Steppe refers mostly to the grasslands of Eurasia, and is taken directly from the Russian

word for this biome.

Pampas is the most common word for the extensive grasslands of mid-southern South America and

is from the Quechua word for plain.

Veldt, the Afrikaans word for field, is a loose term to describe the open upland country

of eastern South Africa that is sometimes grassland but might also be scrub.

Beyond the vernacular terms, grasslands vary more technically in the height of grass, and

in the absence of grazing animals, this relationship is determined by the amount of rainfall and

soil drainage.

Where the soil is wetter, the grass will grow taller, with some species growing up to 4m

in height, while more arid conditions lead to shorter grass.

Anyone who has tried to dig up the turf or sod of their lawn will know how well grasses

bind to the soil, and the tallgrass species also follow this pattern, with roots burrowing

into the earth as deep as their structures are above ground.

As grasses are flowering plants, meadows burst into vivid colour during the season of plant

reproduction which occurs in spring in the mid-latitudes, and at the beginning of the

wet season in subtropical highland areas.

So where in the world do we find the grasslands?

The two northern continents of North America and Eurasia form most of the land area of

this biome with the great plains of their heartlands being made up of prairie and steppe.

The southern hemisphere by comparison has more isolated areas.

The North American prairies extend unbroken in vast plains from Alberta, Saskatchewan

and Manitoba in Canada south and east into the central part of the USA, including the

states of Montana, the Dakotas, Minnesota, Wyoming, Nebraska, Iowa, Kansas, Missouri,

Oklahoma, New Mexico and Texas.

In these regions, the eastern parts receive more rain and are naturally tallgrass prairies

which blend into the temperate forests of the eastern part of that continent.

As we travel west toward the Rockies, less rainfall leads to shorter grass until semi-arid

and scrub conditions occur.

Parts of the “High Desert” of Washington, Oregon, Idaho and Nevada have grassland, as

does the low-lying central valley of California.

In practically all these areas, however, the excellent soils and suitability for wheat

and corn farming have led to decimation of natural prairie, with very few areas remaining.

South America has three areas of grassland.

The first, known as Puna, can be found in upland subtropical areas of the Andes, where

much of this remains preserved in its natural state.

It’s a different story for the Pampas of North-Eastern Argentina, Uruguay and Southern

Brazil, however, where the extensive Pampas has been converted almost entirely to farming,

with ranching dominating.

Lastly, the eastern tip of this continent, from Tierra del Fuego to Southern Patagonia,

as well as the Falkland Islands, are dominated by grasslands in the most polar latitudes

of any in the world.

In Africa, that continent dominated by the tropical Savannah, only a small portion of

it in eastern South Africa is considered a part of the true grassland biome, found in

uplands, where it is known as the Veldt.

We find a surprising area of natural grassland on both islands of New Zealand, a country

otherwise dominated by temperate forests owing to its Oceanic climate.

The causes of these “Tussock” grasslands are poor soils in the centre of the North

Island, and a rain shadow in the South Island east of the Southern Alps that reduces rainfall

significantly.

In the Middle East, we have relatively isolated pockets of grassland in upland areas of Turkey

and the southern Caucasus, while many subtropical areas surrounding the Tibetan plateau have

this biome in a similar way to those of the Andes.

However, these areas pale in comparison to the largest area of grassland on Earth – the

vast Steppe plains of Eurasia.

Running in an unbroken line at around 45°N in latitude, the steppe separates the temperate

and boreal forests of the north from the deserts of the south.

Starting in the west of the continent, in Eastern Europe, they encompass the whole of

the Ukraine and the southern half of European Russia, where most of the natural steppe has

been transformed into the Wheat Belt that feeds these countries in a similar way to

that of the North American prairies.

Further east, the steppe runs along the boundary of Russia and Kazakhstan, and then east again,

ending with the border of Mongolia, where the northern half that country is dominated

by steppe still mostly in its natural state.

Species diversity in natural grasslands is high.

Region by region, we find in the North American Prairie, among others, Big bluestem, Indiangrass

and Switchgrass species.

In the Eurasian Steppe, common species families include Stipa, Festuca and Agropyron.

The eponymous Pampas grass is found in that South American grassland, while the equally

eponymous Veldtgrass (Ehrharta calycina) is from South Africa, and in the New Zealand

tussock grasslands, Chionochloa is common.

Like the savannahs of Africa, the presence of large areas of edible grass in the prairies

and steppes has resulted in the support of vast herds of grazing animals.

In North America there were tens of millions of Bison roaming the prairie before the mass

slaughter of the 1800s.

And let’s not forget that the grasslands of North America and Eurasia led to the evolution

of perhaps the most important animal in human history – the horse.

As mentioned, most of these areas of natural grassland have vanished, being replaced by

agriculture, such is the quality of their soils and climatic suitability for cereal crops.

But unlike other biomes that have been diminished by human activity, the grasslands have, really,

just been adjusted, because what has replaced these grasslands is… just more grass.

The domestication of various species of the grass family into cereal crops is regarded

as one of the key developments of human civilisation.

Wheat, corn, rice, barley, oats, millet, sugar and many more crops that directly, or through

fodder for livestock, feed us, are all grasses.

And so this humble family of plants that colonised the world and later went onto feed ours can

be thought of in many ways as the most important in our world.

And that is the grasslands.

I hope you enjoyed this foray into these green seas.

If you did, please like and share this video, and let me know your thoughts in the comments.

Don’t forget to subscribe, so you don’t miss future episodes.

Thanks again for watching.

I’ll see you in the next part of this series when, for many of you, and myself, we’ll

be coming home – to the forests of the temperate latitudes.