Explain why trophic (feeding) relationships are described as pyramids, and state the average percentage of?
469428
simply because the engery conversion process is inefficent so each level loses some of the engery available in its food so it has to eat more to make up for it.
900998
A food web or food chain is just a representation of what would eat what.  To make one simple list animals making a connections from the prey to the consumer.
307999
The first level consumers are the animals feeding on the plants.  Examples would be mice.  Not to be confused with decomposers, which are the bacteria.
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Think of an ant on top of mount everest,thats relationship between a fish and the ocean.There are over a a trillion fish in the ocean.
753175
Mutualism is a relationship between organisms where both benefit.  In the tundra a classic example of this is the relationship between algae and lichen growing on rocks.  The algae provides sugars for the lichen while the lichen provides a solid substrate for the algae to thrive on.
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In ecology, an ecosystem is a combination of all the living and non-living elements of an area. Ecosystems are the smallest level of organisation in nature that incorporates both living and nonliving factors. They can range in size from as big as the Sahara Desert to as small as a pond. The term microecosystem may be used to describe a very small (often closed) ecosystem.\n\nIn general terms an ecological system can be thought of as an assemblage of organisms (plant, animal and other living organisms—also referred to as a biotic community or biocoenosis) living together with their environment (or biotope), functioning as a loose unit. That is, a dynamic and complex whole, interacting as an "ecological unit."\n\nEarly conceptions of this unit showed a structured functional unit in equilibrium of energy and matter flows between its constituent elements. Others considered this vision limited, and preferred to understand an ecosystem in terms of cybernetics. From this view an ecological system is a functional dynamic onganization, or what was also called steady state. Steady state is understood as the phase of an ecological system's evolution when the organisms are "balanced" with each other and their environment. This balance is achieved through various types of interactions, such as predation, parasitism, mutualism, commensalism, competition, and amensalism. Introduction of new elements, whether abiotic or biotic, into an ecosystem tend to have a disruptive effect. In some cases, this can lead to ecological collapse and the death of many native species. The branch of ecology that gave rise to this view has become known as Systems Ecology. The abstract notion of ecological health attempts to measure the robustness and recovery capacity for an ecosystem; that is, how far the ecosystem is away from steady state.\n\nThe size and scale of an ecosystem can vary widely. It may be a whole forest, a community of bacteria and algae in a drop of water, or even the geobiosphere itself. Different ecosystems are often separated by geographical barriers, like deserts, mountains or oceans, or are isolated otherwise, like lakes or rivers. As these borders are almost never rigid, ecosystems tend to blend into each other. As a result, the whole earth can be seen as a single ecosystem, or a lake can be divided into several ecosystems, depending on the scale used.
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Heterotrophs are organisms which do not make their own food and instead use the food prepared by the autotrophs or the producers.There are three types of heterotrophic nutrition:\n\n1.Saprophytic:In this mode of nutrition,the organisms depend upon the dead and decaying organic(containing carbon or carbon chains) matter.they derive their nutritio from thesesaprophytic heterotrophs depend on dead, decaying organic matter. There are many species of saprophytic bacteria and fungi. Saprophytic decay bacteria and fungi are essential decomposers which recycle vital nutrients back into the ecosystem. .\n.eg - mushrooms,etc.\n\n2.Parasitic:In this mode of nutrition the organism dosn't pre[are its own food.It derives its food from some other organism.The organism fom which it derives its nutrition is called the host.eg\nParasitic nutrition: e.g. taenia (taenia solium - tapeworm). This is an endoparasite, with two hosts. The adult form is found attached on the inside of human intestines, the larval form is found in the pig. The adult is made up of segments called proglottides. At one end is the scolex, which has a double row of hooks and 4 suckers to attatch to the hosts intestine. Lower segments self fertilise and are released in the hosts faeces. It has no digestive system or enzymes it directly absorbs predigested nutrients straight into its body. It has a thick outer coating (tegument) made of protien and chitin, which protects it from the hosts enzymes. It can survive in low oxygen levels. It causes little damage in healthy humans.\n\nHolozoic:Organisms that are holozoic are consumers. Primary consumers are herbivores and Secondary consumers are carnivores, some organ isms feed on both plants and animals and are called omnivores.. Each are specifically adapted to their particular type of nutrition:\n\nHerbivores: e.g. cattle and sheep are herbivores and ruminants. Ruminants digestive systems allow a high proportion of cellulose to be digested. Ruminants have 4 stomachs (rumen, reticulum, omasum and abomasum).\n\n1) food is swallowed and lands in the rumen. This contains bacteria and some protoists annd yeasts. Food remains here for upto 30 hrs. The food is often regurgitated to be chewed again (chewing the cud). The microbes break down the cellulose (with cellulase), into hexoses (breaks poly saccaride b-link). These hexoses are then fermented in anaerobic conditions into organic acids, alos alot of CO2 and methane are belched.\n2) Next food enters the reticulum, sometimes food enters here first. Food moves between the rumen and reticulum fairly freely.\n3) As the food enters the omasum, where water and organic acids are removed. No enzymes are secreted.\n4) From here on it follows a similar path as in the human gut, with enzymes being secreted etc.\n\nNB. many of the bacteria etc are also taken in with the food and digested, which makes protien digestion from the rumen even more efficient, as the microbes can convert low grade protien and urea into a high grade version that can be digested by the cow.\n\nCarnivores: e.g. cat or dog. Their digestive system is more or less the same as humans. The greatest differences being in theeir dentition and other physical and behavioural adaptations which aid their hunting.
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For the population density of say, a large sauropod, which were chiefly herbivorous, they would have had to consume extreme amounts of high energy foods to grow fast.  Since plants require a massive metabolism to digest, their metabolism must have been very slow, which in turn means that they grew slowly.  \n\nA carnivore like your garden variety t-rex, which was also very large, would have had a faster metabolism because he ate (supposedly) large quantities of protein, but still, every organism´s metabolism is dictated by the same rules, so t-rexes must have been slow too, thus indicating that they also grew up pretty slow (considering their size of course).
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The most basic ground rule is that as energy flows from one trophic level (prey) to the higher level (predator) that about 90% of that energy is lost due to respiration.  So if 100 units of energy from phytoplankton are passed to zooplankton and then to small fish you would only get a 1 unit increase in the energy store in the small fish.  So the highest trophic levels have much less energy and are typically large organisms that are not very abundant.
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A symbiotic relationship in which both species benefit.
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ummm everybody seems to have the same answer but yeah\nim assuming your in gr......7 science?\njust cause thats what i am referring to right now in my head:\n\na producer: like a plant/ something that makes its own food[bottom of food chain]\n\nconsumer: an animal/ something that need food by eating something else.\nthere are a bunch of types of producers but i dont remember the names cuz it was too long ago i think it was...so i will number them\n1: 2nd lowest it only eats plants\n2: eats plants and things that eat plants [3rd lowest]\n3: things that eat plants and animals that eat plant/ plants and animals.[highest/us!]\n\nif 1 animal were to lose its habitat, the plant eater would have no food and it would die and then the 2 woulod be able to eat nothing and the 3 would be able to eat nothing cuz the animals and the plants died. its an ecosystem...ect.....symbiosism....ect..\n\nand included in that test should be some stuff about decomposition or something like that\n..\n..\nand some stuff about \nmutualism; when 2 things are benifiting \nex: the sharks and the suckers\n\n__________.[i forgot]; when i thing benifits but the other is not harmed\nex: i cant think of one right now...but it exsists!\n\nparasitism; when i thing benifits and the other is harmed\nex: a tapeworm in a human\n\nendnote: ppl will see this answer and answer it better based on my answer so *cough*i think i should get best answer*endcough* and i totaly am just typing this out of my brain what i learnt 2 years ago so i dont remember much ^_^"""
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I don't understand what you mean by feed.
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from a moron ar the bottom of the food chain that's pretty funny.  they do three things and they do them better than anybody else.  they eat, and make baby sharks, the third is a by product of the eating thing.  BTW they've been around-unchanged-for somewhere around 70 million years.  not bad for a retard, huh.
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Usually, plants take nutrients from the soil and air and use it for fuel for their growth. Animals tap into this cycle by eating plants during this process. A plant species doesn't want to die, so it adapts to make itself harder to eat (thorny, poisonous, hard bark, etc.) and maybe also to take advantage of animal behavior to propogate itself (fruits, nuts, etc.). Animals who can't get easy plant food any more need to adapt too (resistance to poison), and may begin working with the plant to propogate their food source in return for an easy and sometimes exclusive snack or shelter (hummingbirds, etc.). Rarely, plants adapt to the presence of animal food as a booster source of nutrients, especially in nutrient-poor soil (venus fly traps, etc.). Sometimes, plants and animals come to work in such close cooperation that neither would easily survive without the other (honeybees and flowers).\n\nAdaption and evolution is the best way to describe the interactions between plants and animals in a systematic sense.
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There are numerou sub-branches, which can basically be classified in "basic" approaches, that is, disciplines that study one aspect of biology throughout the spectre of living beings, and are thus mainly comparative  (i.e. physiology, anatomy, evolution, genetics, biogeography, etc.) and the "systematic" approaches, which focus on a particular group of living beings (taxon) and study all aspects of it (i.e. zoology, botany, mycology, and specific subtaxa within these major ones). \nThis concept is well represented as a cake in which the "layers" are the basic divisions, and the "slices" are the taxons:\nhttp://uts.cc.utexas.edu/~varanus/cake.gif\n\nThis "cake" depicts the more traditional fields; now more and more disciplines are arising, including the interaction with other sciences.\n\nPS. Your question really looks like homework assignment, and if that's the case, this is not what your teacher will be looking for.
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These are single-celled (unicellular) organisms, and\nhave a well-defined membrane-bound nucleus.\nTheir modes of nutrition may be quite varied.\n• Active feeders: Some protists like Amoeba and\nParamecium (Fig. 23.5) ingest food like most\nanimals. Very often these are also referred to as\nProtozoa (protos: primitive, zoon: animal).\n• Photosynthesizers: Some protists like Euglena\n(Fig. 23.3) have chlorophyll and manufacture\ntheir own food like the plants.\n• Reproduction: Mostly asexual reproduction by\nfission and some reproduce sexually.\n• Occurrence: Many protists live freely in water\nor in soil and many are harmful parasites which\ncause diseases. Some of the protists are\npathogenic, such as Entamoeba histolytica that\ncauses dysentery and Plasmodium vivax that\ncauses malaria.
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The usual example is that of a pond; a self-contained ecosystem.\nNow you need to do your learning and consider how the organisms depend upon one another.