primary consumers (or herbivore)

herbivory is generally restricted to animals eating plants. Fungi, bacteria and protists that feed on living plants are usually termed plant pathogens. Microbes that feed on dead plants are saprotrophs. Flowering plants that obtain nutrition from other living plants are usually termed parasitic plants. More generally, organisms that feed on autotrophs in general are known as primary consumers.


A herbivore is an animal that is adapted to eat primarily plant matter (rather than meat). Although such animals are sometimes referred to as being vegetarian, this term is more properly reserved for humans who choose not to eat meat as opposed to animals that are unable to make such choices. The diets of some herbivorous animals vary with the seasons, especially in the temperate zones, where different plant foods are most available at different times of year.

There is a misperception that if an animal is herbivorous, it represents less danger to humans than a carnivore (or, sometimes, no danger at all). This is not logically sound; few animals, even carnivores, will seek humans as a food source, but any animal will attack a human if necessary to defend itself. For example, in national parks such as the United States' Yellowstone Park, bison represent significantly more danger to humans than wolves, which are likely to avoid people. Of Africa's Big Five game (a term coined by hunters in Africa to refer to the five most dangerous animals to hunt: Rhinoceros, Leopard, Cape Buffalo, Elephant and Lion), three are herbivores.

Herbivores form an important link in the food chain as they transform the sun's energy stored in the plants to food that can be consumable by carnivores and omnivores up the food chain. As such, they are termed the primary consumers in the food chain.


Feeding strategies


Herbivores differ in the extent, specificity and nature of their feeding.

They can be grouped according to which part of the plant they eat: frugivores which eat mainly fruit; folivores, which specialize in eating leaves; nectarivores, which feed on nectar; among herbivorous insects and other arthropods, the level of feeding specialization can be far more fine-tuned, including seed-eaters ("granivores"), pollen-eaters ("palynivores"), plant fluid-feeders ("mucivores"), and those specialized to feed on wood ("xylophages") or roots ("rhizophages"). In other animals, the degree of specialization is not so advanced, however, and many fruit- and leaf-eating animals also eat other parts of plants, notably roots and seeds.

The techniques used to get at the foodstuff are wide and varied, and include the "pierce and suck" technique, surface fluid feeding, hole feeding, margin feeding and skeletonisation.

http://en.wikipedia.org/wiki/Primary_consumers

FOOD WEBS

FOOD WEBS
A food chain shows how each living thing gets its food. Some animals eat plants and some animals eat other animals. For example, a simple food chain links the trees & shrubs, the giraffes (that eat trees & shrubs), and the lions (that eat the giraffes). Each link in this chain is food for the next link. A food chain always starts with plant life and ends with an animal.
Plants are called producers because they are able to use light energy from the Sun to produce food (sugar) from carbon dioxide and water.
Animals cannot make their own food so they must eat plants and/or other animals. They are called consumers. There are three groups of consumers.

Animals that eat ONLY PLANTS are called herbivores (or primary consumers).

Animals that eat OTHER ANIMALS are called carnivores.
carnivores that eat herbivores are called secondary consumers
carnivores that eat other carnivores are called tertiary consumerse.g., killer whales in an ocean food web ... phytoplankton → small fishes → seals → killer whales

Animals and people who eat BOTH animals and plants are called omnivores.

Then there are decomposers (bacteria and fungi) which feed on decaying matter.

These decomposers speed up the decaying process that releases mineral salts back into the food chain for absorption by plants as nutrients.
Image Map of the Nitrogen Cycle - What happens in the soil? Do you know why there are more herbivores than carnivores?

In a food chain, energy is passed from one link to another. When a herbivore eats, only a fraction of the energy (that it gets from the plant food) becomes new body mass; the rest of the energy is lost as waste or used up by the herbivore to carry out its life processes (e.g., movement, digestion, reproduction). Therefore, when the herbivore is eaten by a carnivore, it passes only a small amount of total energy (that it has received) to the carnivore. Of the energy transferred from the herbivore to the carnivore, some energy will be "wasted" or "used up" by the carnivore. The carnivore then has to eat many herbivores to get enough energy to grow.

Because of the large amount of energy that is lost at each link, the amount of energy that is transferred gets lesser and lesser ...
The further along the food chain you go, the less food (and hence energy) remains available.

The above energy pyramid shows many trees & shrubs providing food and energy to giraffes. Note that as we go up, there are fewer giraffes than trees & shrubs and even fewer lions than giraffes ... as we go further along a food chain, there are fewer and fewer consumers. In other words, a large mass of living things at the base is required to support a few at the top ... many herbivores are needed to support a few carnivoresMost food chains have no more than four or five links.

There cannot be too many links in a single food chain because the animals at the end of the chain would not get enough food (and hence energy) to stay alive.

Most animals are part of more than one food chain and eat more than one kind of food in order to meet their food and energy requirements. These interconnected food chains form a food web.

Possible food chains / food webs: Desert Coniferous Forest Deciduous Forest Temperate Rainforest A change in the size of one population in a food chain will affect other populations.

This interdependence of the populations within a food chain helps to maintain the balance of plant and animal populations within a community. For example, when there are too many giraffes; there will be insufficient trees and shrubs for all of them to eat. Many giraffes will starve and die. Fewer giraffes means more time for the trees and shrubs to grow to maturity and multiply. Fewer giraffes also means less food is available for the lions to eat and some lions will starve to death. When there are fewer lions, the giraffe population will increase.

http://www.vtaide.com/png/foodchains.htm

further explaination ecosystem

The U.S. Fish and Wildlife Service defines an ecosystem as a geographic area and all its living components (e.g., people, plants, animals, and microorganisms), their physical surroundings (e.g., soil, water, and air), and the natural cycles that sustain them (e.g., precipitation, drought, fire, grazing). The term ecosystem was coined in 1935 by the British ecologist Sir Arthur George Tansley, who described natural systems in "constant interchange" among their living and non-living parts.

Since that time, scientists have devoted much time and resources toward gaining a better understanding of ecosystem structure and function from the global to localized scale. Part of this work has included developing a National Hierarchical Framework for classifying and mapping ecosystems at different geographical scales. Recognition of ecosystem scale and hierarchy provides managers context from which ecosystem assessment, analysis, and management can occur.

Sitting at the top of the ecosystem hierarchy is the planet's entire living environment, known as the Biosphere. Within the biosphere there are several categories of living communities referred to as ecological units (e.g., domains, divisions, provinces, section, sub-section, etc). Ecological units are generally characterized by their dominant vegetation, such as grasslands, forests, or deserts, and by their different biological and physical potentials.

The structure and function of an ecosystem is largely determined by energy, moisture, nutrient, and disturbance regimes, which in turn are influenced by a variety of biological and non-biological factors, including climate, geology, flora, fire, hydrology, and wind. Ecosystem function depends on inputs, outputs, and the cycling of materials and energy

Ecosystem function is often described biologically in terms of trophic levels. Plant matter in an ecosystem makes up the first trophic level and thus are known as primary producers. A plant's ability to convert energy from the sun into food is a process known as photosynthesis. The second trophic level of an ecosystem, the primary consumers (herbivores), are the animals and insects that obtain their energy solely by eating the primary producers (plants). The third trophic level is composed of secondary consumers, carnivorous animals that feed on herbivores. At the fourth level are the tertiary consumers, carnivores that feed on other carnivores. Finally, the fifth trophic level consists of the decomposers, organisms such as fungi and bacteria that break down dead or dying matter into nutrients that can be used again.

Some or all of these trophic levels combine to form what is known as a food web, the ecosystem's mechanism for circulating and recycling energy and materials. In aquatic ecosystems for instance, microscopic plants (algae) use sunlight to produce energy in the form of carbohydrates. Primary consumers such as zooplankton and small fish feed on the microscopic plant matter, and are in turn eaten by secondary consumers, larger fish such as salmon and trout. Bears play the role of the tertiary consumers in the aquatic food web by catching and eating the salmon and trout. Bacteria and fungi that feed on and decompose the salmon and trout carcasses left behind by the bear enable chemical nutrients tied up in the fish to leach back into the soil and water, where they are absorbed by algae and plants. In this way energy, originally captured by the algae from sunlight, is recycled back into the ecosystem through a complex food web.

http://www.fws.gov/midwest/EcosystemConservation/ecosystem.html

What is an Ecosystem?

Within all species, individuals interact with each other - feeding together, mating together, and living together. Some species have a pecking order as well, and each individual has a role to play within it.

However, it is not only individuals within a species that interact. Different species of animals interact with each other all the time. For instance, animals eat other animals through their interactions in a food web. But plants are included in this web as well as they, too, are eaten by animals.
What would happen if the weather were really cold all the time? Well, not all species of animals, plants and bacteria would be able to survive. What differences are there between species who live in the Rocky Mountains and those who inhabit the Sahara desert? Landscape also determines where plants and animals might live. But what, exactly, is an ecosystem? An ecosystem is a geographical area of a variable size where plants, animals, the landscape and the climate all interact together.

The whole earth's surface can be described by a series of interconnected ecosystems. All living beings form and are part of ecosystems. They are diverse and always changing. Within an ecosystem, all aspects of the environment (both living things and their non-living settings) interact and affect one another. Every species affects the lives of those around them.
A small ecosystem in the boreal forest might look something like this: in the summertime, trees in forests (that produce oxygen used by living things through photosynthesis) lower the temperature in the forest for communities in the hot summer months. In turn, some members of the communities will probably feed upon the tree to gain nourishment, thus affecting or stunting the tree's growth.

Different areas in the world house different ecosystems. For example, you won't find an elephant or a tropical rainforest in Alberta! The different world ecological units are called biomes and they each have different flora, fauna, landscapes and weather patterns. An ecosystem is not the same thing as a biome. A biome is a large unit that is home to many different ecosystems. Within Alberta, there are six different biomes that each have their own specific flora and fauna distribution. These regions are: Grassland, Parkland, Boreal Forest, Foothill, Rocky Mountain and the Canadian Shield, all indicated on the map of Alberta's Regions.

http://www.abheritage.ca/abnature/Ecosystems/intro.htm

ecosystem

from this post onwards, it will be about ecosystem. here is the question:


"how does the energy transfer and nutrient cycles in ecosystem affect the extintion of animals such as the dodo bird?"

it will be break up into different parts
1)defintion on ecosystem
2)information about food web
3)primary consumers and secondary consumers
4)energy transfer in ecosystem
5)extinction of animals
6)focus on how did the dodo bird extinct

more about contraception

this is the very last post on issues on sex.

having so much of information of contraception and vasectomy, along the way as i research, i notice that there is this thing called "emergency contraception" and i think it would be nice to further add in to this biology journal and also to satisfy my curosity.

so what is emergency contraceptive method?

Since the mid 1960s, the use of certain oral contraceptives has been shown to be effective in preventing pregnancy. Two hormonal regimens have proved to be both safe and effective for emergency contraception: combined oral contraceptives and progestogen-only pills. Both can be taken for up to 120 hours after unprotected intercourse. Emergency contraception represents a second chance to prevent an unwanted pregnancy after unprotected sex, and it is particularly responsive to the needs of youths and of women who have been coerced into intercourse.Despite the demonstrated safety and efficacy of emergency contraception, its acceptance by providers and the public, and its inclusion on the WHO's essential drug list, emergency contraception is not widely available in many developing countries (Langer and others 1999).

so thats all for issues on sex the next topic will be on ecosystem.

risk

Risk with vasectomy are few. No death has ever been attributed to this procedure. On the other hand, tubal ligation, a frequently performed surgical sterilization procedure in women, is associated with no fewer than 20 deaths per year. These unnecessary deaths occur because of the risks of the procedure itself, anesthesia complications, and increased ectopic pregnancy rates.

Complications with vasectomy are usually related to bleeding or infection. Prolonged pain sometimes occurs as a result of inflammation along the vas due to sperm leakage (sperm granuloma) or congestion of sperm at the epididymis (epididymitis). These conditions usually go away with rest and anti-inflammatory medication.

Some earlier studies suggested that vasectomy may be associated with an increased risk of heart disease and prostate cancer. According to the National Institutes of Health, research that examined this issue found no evidence that men with vasectomies were more likely than others to develop heart disease or any other immune illness. Other studies, including a recent study of 2,000 men, have shown that the risk of prostate cancer is not increased among vasectomized men.


Fears about the procedure:

Fear can prevent a man from choosing a vasectomy. The following issues are addressed to help a man understand that a vasectomy procedure is simple and safe:

Fear of pain - Men don’t like to think of any procedure near their genitals. Fact: What men need to understand is that an anesthetic is used to numb the area. There is usually no pain or just some pulling after the anesthetic is given. The procedure is usually so well tolerated that upon completion of the procedure, men are frequently surprised that it is over.

Fear of loss of masculinity - Fact: A vasectomy does not affect manliness. A vasectomy does not affect the blood and hormone supply to the penis. The amount and appearance of semen ejaculated will not change noticeably. Of course, during the recovery process, men may be sore, thus making sex less desirable. Later, some men report that sex is actually more enjoyable without the threat of pregnancy. Women may appreciate that their partners have chosen to take the responsibility for sterility (permanent birth control).

Fear of failure of the procedure - Fact: Except for complete abstinence, no method is more effective than vasectomy in preventing pregnancy.

http://www.emedicinehealth.com/vasectomy/page2_em.htm
Belker AM, Thomas AJ Jr, Fuchs EF. Results of 1,469 microsurgical vasectomy reversals by the Vasovasostomy Study Group. J Urol. Mar 1991;145(3):505-11Testes/testicles - Located in the scrotum, the male reproductive glands that produce sperm and male hormonedefintion taken fromMarquette CM, Koonin LM, Antarsh L. Vasectomy in the United States, 1991. Am J Public Health. May 1995;85(5):644-9.