Friday, September 27, 2013

Ecosystem




An ecosystem consists of the biological community that occurs in some locale, and the physical and chemical factors that make up its non-living or abiotic environment. There are many examples of ecosystems -- a pond, a forest, an estuary, a grassland. The boundaries are not fixed in any objective way, although sometimes they seem obvious, as with the shoreline of a small pond. Usually the boundaries of an ecosystem are chosen for practical reasons having to do with the goals of the particular study.


Energy, water, nitrogen and soil minerals are other essential abiotic components of an ecosystem. The energy that flows through ecosystems is obtained primarily from the sun. It generally enters the system through photosynthesis, a process that also captures carbon from the atmosphere. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and other microbes.

Ecosystems are controlled both by external and internal factors. External factors such as climate, the parent material which forms the soil and topography, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem. Other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to periodic disturbances and are in the process of recovering from some past disturbance. Ecosystems in similar environments that are located in different parts of the world can have very different characteristics simply because they contain different species.

 The introduction of non-native species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are also controlled by them and are often subject to feedback loops.  While the resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading.  Other internal factors include disturbance, succession and the types of species present. Although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate.

Terrestrial ecosystem

 A terrestrial ecosystem is an ecosystem found only on landforms. Six primary terrestrial ecosystems exist: tundra, taiga, temperate deciduous forest, tropical rain forest, grassland and desert. A community of organisms and their environment that occurs on the land masses of continents and islands. Terrestrial ecosystems are distinguished from aquatic ecosystems by the lower availability of water and the consequent importance of water as a limiting factor. Terrestrial ecosystems are characterized by greater temperature fluctuations on both a diurnal and seasonal basis than occur in aquatic ecosystems in similar climates.

 The availability of light is greater in terrestrial ecosystems than in aquatic ecosystems because the atmosphere is more transparent than water. Gases are more available in terrestrial ecosystems than in aquatic ecosystems. Those gases include carbon dioxide that serves as a substrate for photosynthesis, oxygen that serves as a substrate in aerobic respiration, and nitrogen that serves as a substrate for nitrogen fixation. Terrestrial environments are segmented into a subterranean portion from which most water and ions are obtained, and an atmospheric portion from which gases are obtained and where the physical energy of light is transformed into the organic energy of carbon-carbon bonds through the process of photosynthesis.

Terrestrial ecosystems occupy 55,660,000 mi2 (144,150,000 km2), or 28.2%, of Earth's surface. Although they are comparatively recent in the history of life (the first terrestrial organisms appeared in the Silurian Period, about 425 million years ago) and occupy a much smaller portion of Earth's surface than marine ecosystems, terrestrial ecosystems have been a major site of adaptive radiation of both plants and animals. Major plant taxa in terrestrial ecosystems are members of the division Magnoliophyta (flowering plants), of which there are about 275,000 species, and the division Pinophyta (conifers), of which there are about 500 species. Members of the division Bryophyta (mosses and liverworts), of which there are about 24,000 species, are also important in some terrestrial ecosystems. Major animal taxa in terrestrial ecosystems include the classes Insecta (insects) with about 900,000 species, Aves (birds) with 8500 species, and Mammalia (mammals) with approximately 4100 species.

Aquatic ecosystem



An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems.

Marine ecosystems cover approximately 71% of the Earth's surface and contain approximately 97% of the planet's water. They generate 32% of the world's net primary production.  They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, in the water. Approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has an average salinity of 35 parts per thousand (ppt) of water. Actual salinity varies among different marine ecosystems.

A classification of marine habitats.


Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides; in this figure it is termed the littoral zone. Other near-shore (neritic) zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web.

Thursday, September 26, 2013

PETUNIA FLOWER

WHITE FLOWER


PLANT DESCRIPTION
  • Fruit / flower: Flower
  • Colour: Colours range from white, red, pink, purple
  • Flowering time: Throughout spring, summer into autumn
  • Flower size:
  • Fragrance: No distinct fragrance
  • Foliage description: unimpressive, sticky leaves
  • Foliage colour: green


Petunia is genus of 35 species of  flowering plants of South American origin, closely related to tobacco, cape gooseberries, tomatoes, deadly nightshades, potatoes and chili peppers; in the family Solanaceae. is great variety: single and double blooms, ruffled or smooth petals, striped, veined or solid colors, mounding and cascading habits and even some fragrance. Most of the petunias sold today are hybrids, developed for specific design purposes.

Petunias are usually carefree growers although they can get pummeled by rain. Even the newer varieties that say they don’t require deadheading will benefit from a pinching or shearing mid-season. When the branches start to get long and you can see where all the previous flowers were along the stem, it’s time to cut them back and refresh the plant.

The 2 oldest types of petunias are grandifloras and multifloras. Both are somewhat mounding. Grandiflora has larger flowers, but Multiflora holds up better in the rain. If you grew petunias a few decades ago, you will remember how the flowers turned to mush, when they got wet.

Tuesday, September 24, 2013

Birds of Paradise flower


crane flower

Birds of Paradise
Native to south America, birds of Paradise is also known as the crane flower. The name comes from the appearance of the bloom which looks similar to exotic, brightly colored birds in flight. Each bloom has 3 blue and orange petals while a few variations have yellow ones. This flower is a symbol of joyfulness and magnificence. The flower can also be used to indicate wonderful and exciting anticipation


He species S. nicolai is the largest in the genus, reaching 10 m tall, with stately white and blue flowers; the other species typically reach 2 to 3.5 m tall, except S. caudata which is a tree of a typically smaller size than S. nicolai. The leaves are large, 30–200 cm long and 10–80 cm broad, similar to a banana leaf in appearance but with a longer petiole, and arranged strictly in two ranks to form a fan-like crown of evergreen foliage. The flowers are produced in a horizontal inflorescence emerging from a stout spathe. They are pollinated by sunbirds, which use the spathe as a perch when visiting the flowers. The weight of the bird when standing on the spathe opens it to release the pollen onto the bird's feet, which is then deposited on the next flower it visits.

Monday, September 23, 2013

Vultures and traditional medicine




Vultures are used in southern Africa as traditional medicine 
by a number of ethnic groups for a wide range of purposes, and recent research has for the first time attempted to quantify the extent 
of such use. Considering the impacts of other factors such as habitat loss, electrocutions, collisions 
with man‐made structures and direct or indirect poisoning, the extent of harvest of vultures for traditional medicine is a threat to the continued survival of a number of species of vultures.  This ultimately threatens the survival  of traditional  customs  and  belief systems  which rely  on the continued presence and use of vultures. 

Use of vultures is an important component of traditional medicine, particularlyin southern Africa and there is evidence to suggest that traditional use is at least partly responsible for the rapid decline of vulture populations in the subcontinent. There is a widely held belief

in many African cultures that health, disease, success or misfortune are not chance events but the result of the active influence of individuals or ancestral spirits. For this reason, traditional medicine is held in high esteem in such cultures and is regularly used by a large proportion of the population. Traditional

medicines represent herbal, animal and mineral material used for physiological as well as symbolic/psychological purposes. Approximately 80% of the population in South Africa uses traditional medicine in one form or another because pharmaceutical drugs are too expensive or traditional methods are considered more appropriate.

health benefits of carrots



1. Carrots are known to be good for the overall health and specially organs like the skin, eyes, digestive system and teeth. One of carrots' fat-fighting features is their respectable fiber content, half of which is the soluble fiber calcium pectate. Soluble fiber may help lower blood-cholesterol levels by binding with and eliminating bile acids, triggering cholesterol to be drawn out of the bloodstream to make more bile acids.

2.  Cancer Prevention

Studies have shown carrots reduce the risk of lung cancer, breast cancer and colon cancer. Researchers have just discovered falcarinol and falcarindiol which they feel cause the anticancer properties.

Falcarinol is a natural pesticide produced by the carrot that protects its roots from fungal diseases. Carrots are one of the only common sources of this compound. A study showed 1/3 lower cancer risk by carrot-eating mice.

3.  Anti-Aging

The high level of beta-carotene acts as an antioxidant to cell damage done to the body through regular metabolism.  It help slows down the aging of cells.

4.  Healthy Glowing Skin (from the inside)

Vitamin A and antioxidants protects the skin from sun damage. Deficiencies of vitamin A cause dryness to the skin, hair and nails. Vitamin A prevents premature wrinkling, acne, dry skin, pigmentation, blemishes, and uneven skin tone.

5.  A Powerful Antiseptic

Carrots are known by herbalists to prevent infection. They can be used on cuts – shredded raw or boiled and mashed.

6.  Beautiful Skin (from the outside)



Carrots are used as an inexpensive and very convenient facial mask.  Just mix grated carrot with a bit of honey. See the full recipe here: carrot face mask.