How do plants obtain the nitrogen they need?
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*Some plants (like legumes - ie peas) form a relationship with microorganisms (Rhizobium sp.). This
happens in their roots, and nodules are formed. these microbes can take nitrogen from the air (which is
about 80% nitrogen) and turn it into ammonia, which is absorbed by the plants root.
*they absorb it in dissolved form from the water in the soil as NH4+ or as NO3-
*Plants must have nitrogen in the form of nitrates or ammonia. They get these from the soil
where they are taken up by the roots.
How do herbivores obtain the nitrogen they need?
Herbivores obtain nitrogen just like any other animal - through the air, which is mostly composed of
nitrogen. However, organic nitrogen that can be used in proteins is only found in autotrophs.
Through the nitrogen cycle, atmospheric nitrogen is fixed as organic nitrogen which is assimilated by
Herbivores, like omnivores and carnivores, get their nitrogen from food. The trick is getting the
nitrogen "fixed" into the food in the first place. About 80% of earth's atmosphere is nitrogen, but
atmospheric nitrogen is very nearly inert (the triple bond between the nitrogen atoms is difficult to
break). It does not readily engage in chemical reactions, so plants and animals cannot get their
nitrogen by breathing. Oxygen, on the other hand, reacts easily, so you'll find that you can get the
oxygen you need directly from the atmosphere.
Plants extract carbon directly from the atmosphere--from carbon dioxide and photosynthesis. That
carbon, plus water and some other ingredients, produce the carbohydrates and other nutrients we
get from plants. But like us, plants can't capture atmospheric nitrogen. They have to get the nitrogen
they need for proteins & DNA from another source.
So how does nitrogen get fixed into plants? Primarily via nitrogen compounds in the soil. There is a
bit of nitrogen in any soil, thanks to decaying plants & animals and the activity of certain types of
bacteria. But if you farm the soil intensively, you can quickly exhaust the naturally occurring
One way to build up the nitrogen in soil is to exploit a symbiotic relationship between certain types of
bacteria and a few types of plants. Bacteria that grow on the roots of some bean plants convert
atmospheric nitrogen into compounds that stay in the soil. This is the phenomenon behind crop
rotation with soy beans--you let the bacteria on the soy bean's root replenish the nitrogen in the soil.
Then crops you grow in that soil pass that nitrogen through the food chain. For example, an
herbivore might eat the crop directly, or a carnivore could eat the flesh of an herbivore that ate the
crop that grew in the field that once grew soy beans that hosted nitrogen-fixing bacteria.
Another way to get the nitrogen into the soil is via animal waste. Manure contains a good deal of
fixed nitrogen. Hence the smell that bothers city folk when they visit farm country.
Today, a good deal of the nitrogen in crops comes from manufactured fertilizer. The Haber-Bosch
chemical process, developed about a hundred years ago, draws nitrogen from the air and fixes it in
forms that can be used for fertilizer (or explosives.) About half of the nitrogen in your body came
from the atmosphere via the Haber-Bosch process. (See "The Alchemy of Air" by Thomas Hager,
2008, for more on the history of Haber-Bosch.) Without Haber-Bosch, a couple billion of us humans
would not be alive.
What would be the impact on the nitrogen cycle if there were
a decrease in decomposition in a given ecosystem?
The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect
the rate of key ecosystem processes, including primary production and decomposition.
The Nitrogen Cycle
The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms.
This transformation can be carried out through both biological and physical processes. Important
processes in the nitrogen cycle include fixation, ammonification, nitrification, anddenitrification. The
majority of Earth's atmosphere (78%) isnitrogen,
making it the largest pool of nitrogen. However,
atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in
many types of ecosystems. The nitrogen cycle is of particular interest toecologists because nitrogen
availability can affect the rate of key ecosystem processes, including primary
production anddecomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen
fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle
A 2011 study found that nitrogen from rocks may also be a significant source of nitrogen, that had not
previously been included in most calculations and statistics.
("self-feeding", from the Greek (e)autos "self" and trophe"nourishing") or "producer", is an
organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) from
simple substances present in its surroundings, generally using energy from light (photosynthesis) or
inorganic chemical reactions (chemosynthesis). They are the producers in a food chain, such as plants on
land or algae in water. They are able to make their own food, and do not need a living energy or
organiccarbon source. Autotrophs can reduce carbon dioxide to make organic compounds, creating a
store of chemical energy. Most autotrophs use water as the reducing agent, but some can use other
hydrogen compounds such as hydrogen sulfide. Phototrophs, a type of autotroph, convert physical
energy from sunlight (in case of green plants) into chemical energy in the form ofreduced carbon.
Autotrophs can be phototrophs or chemotrophs. Phototrophs use light as an energy source, while
chemotrophs utilize electron donors as a source of energy, whether from organic or inorganic sources;
however in the case of autotrophs, these electron donors come from inorganic chemical sources. Such
chemotrophs are lithotrophs. Lithotrophs make use of inorganic compounds, such as hydrogen sulfide,
elemental sulfur, ammonium andferrous iron, as reducing agents for biosynthesis and chemical energy
storage. Photoautotrophs and lithoautotrophs use a portion of the ATP produced during photosynthesis or
the oxidation of inorganic compounds to reduce NADP
to NADPH in order to form organic compounds.
A heterotroph (/ˈhɛ tərɵ troʊ f/; ἕ τερος heteros = "another", "different" and τροφήtrophe = "nutrition") is
an organism that cannot fix carbon and uses organiccarbon for growth.
This contrasts with autotrophs,
such as plants and algae, which can use energy from sunlight (photoautotrophs) or inorganic compounds
(lithoautotrophs) to produce organic compounds such as carbohydrates, fats, and proteins from
inorganic carbon dioxide. These reduced carbon compounds can be used as an energy source by the
autotroph and provide the energy in food consumed by heterotrophs.
A herbivore is an animal anatomically and physiologically adapted to plant material, for example foliage,
as the main component of its diet. These animals have an all plant diet and have characteristics that are
special for obtaining plant material. (ex. Teeth for chewing tough plant parts)
A carnivore /ˈkɑ rnɪ vɔ ər/ meaning 'meat eater' (Latin, caro meaning 'meat' or 'flesh'
and vorare meaning 'to devour') is an animal that derives its energy and nutrient requirements from
a diet consisting mainly or exclusively of animaltissue, whether
through predation or scavenging.
Animals that depend solely on animal flesh for their nutrient
requirements are considered obligatecarnivores while those that also consume non-animal food are
Omnivores also consume both animal and non-animal food, and apart
from the more general definition, there is no clearly defined ratio of plant to animal material that would
distinguish a facultative carnivore from an omnivore.
A carnivore that sits at the top of the foodchain is
an apex predator.
Plants that capture and digest insects are called carnivorous plants. Similarly,fungi that capture
microscopic animals are often called carnivorous fungi.
An omnivore, meaning 'all-eater' (Latin omni, vorare: "all, everything", "to devour"), or polyphage ("many
eater") species is a consumerof a variety of material as significant food sources in their natural diet.
These foods may include plants, animals, algae and fungi.
Omnivores often are opportunistic, general feeders with neither carnivore nor herbivore specializations for
acquiring or processing food, and are capable of consuming and do consume both animal protein and
Many omnivores depend on a suitable mix of animal and plant food for long-term good
health and reproduction.
What is Decomposers?
Decomposers (or saprotrophs) are organisms that break down dead or decaying organisms, and in
doing so carry out the natural process ofdecomposition.
Like herbivores and predators, decomposers
areheterotrophic, meaning that they use organic substrates to get their energy,carbon and nutrients for
growth and development. Decomposers can break down cells of other organisms using biochemical
reactions that convert the prey tissue into metabolically useful chemical products, without need for
Decomposers use dead organisms and non-living organic compounds as their food
What trophic level do decomposers belong to?
Decomposers belong to the last trophic level, since they consume the dead organisms, its around the fourth or
Decomposers are last in food chains, so they can be 4th or 5th trophic level depending upon the food chain or
-ter. or quatr. and so on consumers
Why do food chains usually only have 3-5 levels?
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Because at each trophic level, 90% of the total energy is lost through basic body functions. The higher up
on the food chain you are, the less energy there is available.
Ten percent rule: only ten percent of the energy in any trophic level is available for the next trophic level.
The higher you feed in the food chain the less energy is available.
Because a huge amount of energy is lost in between each level. Something around 80%, I believe.
Whats the difference between a food chain and a food web?
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A food chain is a single line of organisms, where each is preceded by something that it consumes and is
followed by something that consumes it. A food web branches out in all directions with arrows pointing
from organisms to any number of organisms that consume it.
The food chain refers to a natural system by which energy is transmitted from
one organism to another. When we refer to these systems on an ecological
basis, we use the term food web.
A food chain refers to four main parts. These are:
* The sun – this is the primary source of energy for all organisms
* The producers – these are the plants. They are called producers because they
are the only part of the food chain that produces their own food, as well as the
food for other organisms. In fact, the oxygen that all living things breathe in is
a result of the food producing process of the plants (photosynthesis). The food
that other organisms take in is also a result of the photosynthesis in plants
that produces glucose.
* The consumers – this refers to the group of organisms that eat something
else. They may be herbivores (plant eating animals) or carnivores (flesh eating
animals). They also include parasites and scavengers.
* The fourth in the food chains are the scavengers. These are the fungi and
bacteria that we look down on with such disgust. They are an all important
part of the food chain because they convert all dead matter into nitrogen and
carbon that is released into the atmosphere. Without the hard work put in by
these scavengers the earth would just be one large garbage bin that was never
A food web on the other hand refers to a bunch of food chains that make up an
ecosystem. It is a mass of connected food chains that are interlinked at various
points. For instance, there may be links running between grass and all the
animals that eat grass e.g. the goat, cow etc. Then there would be a link
between those animals and other animals that ate them, for instance the lion,
A food chain describes a pattern through which energy is transmitted from the
producers or the plants to the decomposers. For instance, it would perhaps
describe how a tiny fish survive on plankton, while the larger ones survive on
A food web on the other hand would also include the big fish that were feeding
on the plankton as well. It basically depicts a broader picture of all
interconnected food chains that exist within an ecosystem.
A food chain is a description of a single link between the origin of the source of
energy and its final recipient. A food web includes all such chains that make
up an ecosystem. It can be described as a collection of individual and
interlinked food chains!
Both food chains and the food web have been adversely affected by the
onslaught of human civilization. In order to make our habitat more
‘conducive’, we are causing the destruction of valuable parts of the food chain
and the food web. For instance, the use of pesticides is having an adverse
effect on most of the eco systems. Man must realize that they are a part of the
food chain and that their welfare is dependent on others also!
Basically any type of plant that produces its own food.
(some exampls: zebras, fish, lizards, lions, toucans, koalas, giraffes, deer, tigers, foxes, crocodiles,
sting rays, penguins, walruses, otters, badgers, sea lions, beavers, dolphins, antelope, chickens,
Canrnivores are the animals which purely feed on flesh of other animals.
Here are some examples of animals that are carnivores:
A carnivore is an animal that gets food from killing and eating other animals; they literally live on other
An omnivore is an animal which eats both meat and plant matter. Examples would be Bears,
Hedgehogs, Pigs, Rats, Chickens and Piranhas.
Hedgehog , possum, Pigs, Chimpanzee , raccoon, skunk, sloth , CHICKEN, some lizards, humans,
cat, raven, and roadrunner.