Taiga ecosystem~^^

Taiga ecosystem:~



::=>> Conifer forests of the taiga biome .


ღ“Taiga” is a Russian word meaning dense evergreen forest. The taiga biome, the largest biome on land, is full of dense evergreen forests. Located just south of the tundra in the northern parts of Europe, Asia, and North America, these forests of conifer trees are also known as boreal forests.

ღ It is very cold and snowy in the taiga during winter, with below freezing average temperatures. During winter it can get as cold as −50°C in the taiga and is typically below freezing. There is a very large temperature difference in winter and summer. While it is not uncommon for temperatures to dive below freezing during the summer as well, it is generally warmer then. During summer the taiga can be as warm to 30°C. Days are long during summer in the taiga, ice thaws, snow melts, and it is often rainy.

ღ The land surface of the taiga was covered with ice until about ten thousand years ago when the glaciers of the last Ice Age retreated. As they melted back, they left the land surface with depressions that have since become small lakes and bogs. Soils have only had a relatively short amount of time to form since the glaciers retreated and so are often thin and they can be nutrient poor because of the cold climate too.


ღ Conifer trees like spruce and fir thrive in this climate. The trees grow close together. This protects them from cold and wind. Their dark color makes their albedo low and they absorb solar energy readily, keeping them a bit warmer. There are a few deciduous tree species that can live in the taiga as well including birch and aspen, but they are not common.

ღ Many animals make their home in the taiga for at least part of the year. Some stay year-round. In the summer, birds and insects are abundant. Many bird species migrate to the taiga and breed and nest there during summer. Other birds, such as sparrows and crows, stay in the taiga year-round. Mammals include herbivores like rabbits and voles as well as carnivores such as lynx, wolverines, and bobcats.



► Taiga ecosystem.

Tundra Ecosystem

Tundra ecosystem:~



♥ Tundra in the Western Andreafsky Wilderness of Alaska (U.S.).


In the very cold places of the world, survival isn't easy. The soil is frozen, its top surface thawing only during summer, and no trees can grow. Yet plants and animals that are adapted for the harsh conditions thrive. This biome is called tundra. Most of the world's tundra is found in the Arctic. It is called Arctic tundra. There is a small amount of tundra on parts of Antarctica that are not covered with ice. Plus, tundra is found on high altitude mountains and is called alpine tundra.

Permafrost is the term given to frozen soil. During the winter months, permafrost reaches the surface of the tundra. It is very cold during the winter, with temperatures reaching -60 degrees Fahrenheit (-51 degrees Celsius). Very few animals are active in these harsh conditions.

In the summer time, the tundra changes. The Sun is out almost 24 hours a day, so the tundra starts to warm up. The permafrost melts at the surface, and plant life grows. However, the permafrost only disappears for a few inches below the surface. There isn't enough soil for trees to grow, so only small plants are found in the tundra.

At the same time, a variety of animals come out to feast on the plants. Insects come to feed on the animals, and birds appear to enjoy the insects.




♥ Tundra are among Earth's coldest, harshest biomes. Tundras ecosystems are treeless regions found in the Arctic and on the tops of mountains, where the climate is cold and windy and rainfall is scant. Tundra lands are snow-covered for much of the year, until summer brings a burst of wildflowers.



♥ Mountain goats, sheep, marmots, and birds live in mountain, or alpine, tundra and feed on the low-lying plants and insects. Hardy flora like cushion plants survive on these mountain plains by growing in rock depressions where it is warmer and they are sheltered from the wind.

Tropical Rainforest ecosystem

♥Tropical rainforests are home to thousands of species of animals, plants, fungi and microbes. Scientists suspect that there are many species living in rainforests have not yet been found or described.

♥ The consumers such as insects, birds, squirrels and monkeys reproduce very well and are large in numbers. It is because there is sufficient water supply, suitable temparature and stable environment.

♥There are areas of rainforests where plants are densely packed. Areas where sunlight can reach the surface are full of interesting plants. In other areas a canapy, made from the branches and leaves of tall trees, shades the ground below, preventing smaller plants from growing.

♥Rainforests get their name because they receive a lot of rain - an average of 80 inches (203 cm) a year! Rainforests are found at and near the equator, where it is always warm and muggy. The temperature doesn't change very much during the year.

♥The famous Amazon jungle is located in Brazil, in South America. This particular forest is called the Neotropics. Other large blocks are located in Central and West Africa.



△ Rainforest vegetation on the Caribbean island of Dominica.

Desert ecosystem

Desert ecosystem:~
♫ Desert plants and animals have adapted well to the arid climate by having structure which can reduce water loss and store water. Solar energy that green plants convert into food fuels life here. Although in most ecosystems plants compete for sunlight, here most plants are adapted to minimize the effects of too much solar energy.

♪ Examples such as:~

► Cacti~ They have to hold water inside them to stay alive. Cacti are the most
famous desert plants.

► Some of the animals neither drink nor excrete sweat.( They use the water in food
repeatly)~ Examples: Camel

► Some animals spend the day in the burrows and go out at night.

► After a rainfall, part of the desert changes into a beautiful garden.



ΨThe above picture is an example of an undisturbed desert ecosystem with a healthy distribution of shrubs and grasses.

Grassland ecosystem

Grassland Ecosystems:~
◆Over one quarter of the Earth's surface is covered by grasslands. Grasslands are found on every continent except Antarctica, and they make up most of Africa and Asia. There are several types of grassland.They are distinguished by different names like plains, prairies, savannas and pampas.

◆Grasslands develop where there isn't enough rain for forests but too much rain for deserts. Grasslands are filled with grass. There are many types of grass, though. Fields of wheat are considered grasslands, even though they are often cultivated by people. Grass is special because it grows underneath the ground. During cold periods the grass can stay dormant until it warms up. The living condition is very poor on grassland.

◆Examples such as:~
★Zebra,kangaroo and other animals run and jump as they adapt to their environment.
★The badger, rabbit and fox hide during the day time in theis burrows.
★Some birds build their nests on the ground surface.






◆Grassland ecosystems in British Columbia generally occur in areas where the climate is hot and dry in summer and cool to cold and dry in winter. The parent material is often composed of fine sediments, and grasslands are most often in valley or plateau landscapes. The organisms that live in them include plants and animals that have adapted to the dry climatic conditions in a variety of ways.

◆Differences in elevation, climate, soils, aspect, and their position in relation to mountain ranges have resulted in many variations in the grassland ecosystems of British Columbia. The mosaics of ecosystems found in our grasslands, including wetlands, riparian areas, aspen stands and rocky cliffs, allow for a rich diversity of species.



ΨThe food pyramid(Grasslands ecosystem)above describes the relative numbers, population porpotions and primary elements of the food chain in grassland ecosystem.

◆Some grassland plants, such as grasses, have many long, fine roots to search for water at and just below the surface; others, such as big sagebrush, have long tap roots that penetrate deep below the surface to find water. Many animals migrate or dig burrows underground for protection and to avoid cold winter or hot summer temperatures.

Ecosystem

Ecosystem:~

☆An ecosystem is a natural unit consisting of all plants, animals and micro-organisms (biotic factors) in an area functioning together with all of the non-living physical (abiotic) factors of the environment.

★An ecosystem is a completely independent unit of interdependent organisms which share the same habitat.

☆Ecosystems usually form a number of food webs which show the interdependence of the organisms within the ecosystem.

★ The physical environment consists of water, air, soil, sunlight, minerals and temparature that make up the non-living part of the ecosystem.



Ocean ecosystem:

Perch in giant kelp forest
Click on image for full size (425 Kb)
Courtesy of NOAA

The ocean holds the largest of all biomes on Earth. It covers 70% of the planet’s surface.

Life in the ocean is diverse. The smallest creatures that call the ocean home are microscopic and made of a single cell( algae).The largest creatures are blue whales, which can be as much as 34 meters (110 feet) long. There are many different ways to live in the ocean too. Some animals travel thousands of miles through ocean water while others stay in the same place on the ocean floor for their entire lives. Some burrow beneath the sand while others float near the water surface.

The ocean is not uniform, nor is the marine life within it. While life in the ocean is often described as one biome, there are actually many specific ecosystems within the ocean that are characterized by physical conditions such as water temperature, the amount of sunlight that penetrates through the water, and the amount of nutrients.

Sunlight penetrates the top layer of ocean water, as much as 200 meters (656 feet) deep. This allows phytoplankton, algae, and plants like seagrass to make their own food through the process of photosynthesis. Almost all marine life (about 90%) lives within this top, sunlit layer of the ocean. Photosynthesizing organisms are the start of most marine food chains except for those in the deep ocean where there is no sunlight.

The temperature of ocean water varies depending on its location. Closer to the Earth’s polar regions, ocean water is colder. Closer to the equator, ocean water is warmer. Water that is deep in the ocean is colder than water that is near the ocean surface. Many animals can only survive at certain temperatures. Other animals in the ocean are able to survive at a range of temperatures and can live in more places in the world’s ocean basins.



═☆　The underwater observatory gives scientists the ability to observe and begin to unravel all the factors that combine to sustain the oceanic ecosystem—how fresh water, plant detritus, sediments, chemical, and other materials run off the coasts; how they mix into the sea, increase turbidity, change the penetration of light, and add nutrients; how all these influence marine life, from microscoic plants to corals and fish; and how these change after storms and over seasons.




═☆　This graphic shows a simplified version of how carbon and phosphorus cycle through the upper ocean ecosystem before settling to the bottom. The two subclassifications of phosphorus shown are phosphate (H2PO4) and dissolved organic phosphorus (DOP).




═☆　Ocean ecosystems are increasingly threatened by overfishing, pollution, habitat loss, climate change and coastal development. Understanding why some ecosystems resist these shocks, and continue to deliver benefits such as plentiful fish and pristine beaches, and how others collapse is the subject of resilience science.




Ψ Most of the remaining population of critically endangered Hawaiian monk seals lives in the Northwestern Hawaiian Islands.

Modified roots

Modified Roots:( Metamorphic Roots)

Modified roots are roots which change their structures to adapt to their environment.
There are seven types of modified roots:

a) Prop roots:
Prop roots grow from the stem to the ground. They give extra support to the plants. Examples: Ficus, maize, mangrove, pandanus.









b) Buttress roots:
Buttress roots are large roots on all sides of a tall or shallowly rooted tree. Typically they are found in rain forests where soils are poor so roots don't go deep. They prevent the tree from falling over and help gather more nutrients. They are there to anchor the tree and soak minerals and nutrients from the ground, a function that would prove difficult if the tree was unsoundly rooted. Examples: gossampinus(silk cotton), casualrina, flame of the forest.


c) Aerial Roots:

Aerial roots are roots above the ground. They are almost always adventitious. They can absorb water from the air.They are also used to hold on to their support. They are found in diverse plant species, including epiphytes also known as air plants, which includes the orchids, tropical coastal swamp trees such as mangroves.

d) Clasping roots:

Clasping roots grow from the nodes of the soft stem to cling on to other plants. Examples: pepper, ivy

e) Storage roots:
Storage roots are swollen with nutrients and water to prepare for unfavourable conditions. Some are swollen main roots. Examples: carrot. Others are swollen branched roots or advertitious. Example: Cassava, sweet potato.

f) Respiratory roots:
Some plants in swampy areas have branch roots that grow upwards, through the mud and into the air. The exposed parts of the roots are spongy and they take in air for respiration. Examples: red mangrove








g) Parasitic Roots
Some plants live on other plants and get food materials from their hosts. Parasitic roots are used to absorb food materials form their hosts. Examples: Dodder, mistletoe








The functions of roots are:

1) To absorb water and inorganic nutrients

2) Anchoring of the plant body to the ground

3) As a storage of water

4) Reproduction