Download Food Webs and Symbiosis-Rainforests and Taiga

Rainforest Food Web The list of plants and animals endemic to rainforest biome is exhaustive, and that makes the rainforest food web one of the most complex food webs of the world. Continue reading... More than half of all the living organisms on Earth are found in the rainforest biome -­‐ one of the richest biomes of the world. These rainforests are typically characterized by dense overgrowth which makes it virtually impossible for sunlight to reach the ground. This biome also boasts of some of the most fascinating animal adaptations in kingdom Animalia. There is no doubt about the fact that this biome is one of the most interesting componenst of world ecosystem. On the basis of location, the rainforest biome is divided into two parts -­‐ the tropical rainforest and the temperate rainforest. The two differ from each other in terms of climate, flora and fauna -­‐ and this difference is very well highlighted in their respective food webs. Tropical Rainforests As its name suggests, the tropical rainforest biome spans across the tropical regions of South America, Asia, Central America, Africa, Australia as well as some islands in the Pacific Ocean. In terms of biodiversity, tropical rainforests are home to approximately 80 percent of the total plant and animal species on the planet. These rainforests are typically characterized by presence of tall trees, with height ranging between 60-­‐100 meters. The long list of animals which have a key role to play in the tropical rainforest energy pyramid include jaguars, monkeys, bats, chimpanzees, and several species of insects and reptiles. Temperate Rainforests The temperate rainforests are relatively sparse, and restricted to some regions in North America, South America, Asia and Australia. Basically, temperate rainforest vegetation is made up of coniferous or broadleaf tree species. Most of these species do not require sunlight for the process of germination, and that explains the abundance plants in the rainforest with very little amount of sunlight reaching the ground. The animal species native to this region include cougars, bears, wolves, deer, elks as well as a wide range of small mammals, reptiles and insects. Rainforest Food Web Tertiary Consumers: These are the apex predators, which are exclusively carnivorous in nature, and feed on primary as well as secondary consumers. In tropical rainforests, the distinction of being apex predators is shared by the jaguar and python. In temperate rainforests, on the other hand, the apex predators are cougars, bears, and lynx cats. ↓ Secondary Consumers: Most of the secondary consumers are carnivores, which feed on primary consumers, while some are omnivores, which feed on primary consumers as well as producers. This group includes animals such as iguanas, snakes, etc. and temperate rainforest animals such as weasels, raccoons, woodpeckers, etc. ↓ Primary Consumers: These are various herbivores (as well as some omnivores and insectivores) which feed on the producers (plants). The tropical rainforest animals featuring in this group include deer, monkeys, squirrels, grasshoppers, etc. In temperate rainforests, primary consumers include monkeys, snakes, elks, and other small mammals. ↓ Producers: As in any other food web, even in tropical rainforest food web the producers include plants. Some of the most prominent plants include Sawpalm, Twisty grass, Live Oak, Parasol Plant, Cedar, etc. In temperate rainforests, plant species which act as producers in the food web include cedar, fir, spruce, hemlock, etc. ↓ Detritivores: Other than the producers and consumers, the food webs include yet another group known as the detritivores -­‐ which consist of bacteria and fungi. These detritivores decompose plant matter and dead animals, and add it to ground in form of nutrients, which are eventfully used by plants to produce their own food. When we talk about food webs or food chains, we need to understand that these biological attributes of nature have evolved over the period to reach this stage. All the animal species and plants featuring in the rainforest food chain diagram given above are dependent on each other to a great extent, and extinction of a single species can result in serious imbalance in the entire ecosystem. Of late, human encroachment on pretext of agriculture and mining is being seen as biggest threat to the rainforest. If this trend continues, these rainforests will disappear from the planet within a few years, and so will all the animals and plants which are endemic to them. Mutualism in the Rainforests The relationship between the capuchin monkeys and flowering trees in the tropical rainforests is the best example of mutualism in this biome. When the capuchin monkey feeds on nectar in these flowers by lapping it up, it gets pollen on its face -­‐ which it eventually transfers to other flowers in the process of feeding on them. In this way, the trees provide the capuchin species with food, while the capuchin monkey facilitates pollination of flowers of this tree. Commensalism in the Rainforests The relationship between Ecitoninae -­‐ the New World army ants, inhabiting the rainforest floor and antbirds -­‐ small dull-­‐colored South American bird species, is the best example of commensalism in rainforest. These army ants are notorious for their tendency to take on anything that comes in their path while they march the forest floor. The antbirds, on the other hand, follow this swarm of ants and feed on whatever is left behind after the ants are done with their share. The ants manage to shake the floor as they march and the ruffles insects on the floor fly up and are eaten by the antibirds. In this way, the antbirds benefit from the army ants, but the army ants are not benefited from the antbirds. Parasitism in the Rainforest You can't actually call this a relationship, but the dependence of phorid fly on leaf-­‐cutter ants is the best example of parasitism in the tropical rainforest biome. When these leaf-­‐
cutter ants are collecting leaves, the phorid flies attack them and lay their eggs in the crevices of the worker ant's head. When the eggs hatch, the larvae burrow into the ant's body and feeds on it, thus killing the ant. In this manner, the phorid fly gets benefited from the leaf-­‐cutter ants, but the leaf-­‐cutters have to bear the brunt of their dependence. An ecosystem that flourishes in regions near the equator is known as tropical rainforest ecosystem. The food chain or web flourishing in this ecosystem is termed as tropical rainforest food web chain. About 90% of species of world's insects and animals are found in the rainforests. Study of a food chain provides us with information about which organisms act as predators and prey in a particular ecosystem. An understanding of the links that hold together a food web is obtained through a detailed study. The Phenomenon of Food Web The predator-­‐prey relationship between species of a particular ecosystem is represented by a food web. A food web is influenced by many different environmental factors and also geography of the region. Some of the basic elements however, remain the same in food webs across different habitats. Basic elements of the food webs include autotrophs (that generate energy through photosynthesis), herbivores and carnivores. Food Web The food web of tropical rainforests is highly complicated and many different food chains are interlinked through this biome. The food web is complicated which makes it difficult to find out the exact number of chains/links. However, it can be classified roughly into 4 levels. The first level includes plants (leaves, flowers & fruits), plankton, larvae, spiders and insects. Plankton eaters and insects along with plants are at the second level. The different types of plankton eaters include fish, frogs, possums, bandicoots, birds, echidnas, kangaroos and wallabies. Such types of creatures are abundant in nature and form the diet of those placed above in the hierarchy. Small-­‐
sized animal eaters are placed at the third level of food web. Quolls, snakes, platypus, dunnarts, owls, kookaburras, etc. are the small animal eaters at this level. Bigger carnivores like crocodiles, pythons, feral cats, dingoes and feral dogs are placed at the top (fourth) level. Thus, carnivores are at the top and plants at the base of this tropical rainforest food pyramid. For example, dingoes (Canis lupus dingo) find themselves at the top of the food pyramid in Australian rainforests. The different organisms mentioned in 4 levels of the food chain are dependent on each other for obtaining nutrition. Those organisms perched on the topmost tier feed on those at the bottom. Scavengers or decomposing microbes feed on top-­‐level organisms after their death. Organic matter formed as a result of decomposition gets mixed in the soil and thus, food cycle is completed. Energy Flow in Food Web As we have seen in the paragraph above, plants form the foundation of this food web and some carnivores attain the top-­‐position. However, flow of energy is a common factor which binds the members of food chain together. Energy originating from the sun is disintegrated through the process of decomposition. Plants use the process of photosynthesis to prepare food for themselves. A chemical called chlorophyll plays an important role in the process of photosynthesis. Solar energy is used in the conversion of carbon dioxide and water into sugars. Polymerization of sugars facilitates their storage and thus, long-­‐chain carbohydrates are formed. The sulfates, nitrates and phosphates present in soil are used in the preparation of proteins. The proteins and carbohydrates prepared by plants are used as a source of energy by herbivores and eventually carnivores. Biomass goes on decreasing from the base of food pyramid to its pinnacle. The reason behind it is the loss of energy in the environment which results from entropy. Understanding a food web in totality, due to its complicated nature is quite a difficult job. The varied nature of an ecosystem gives rise to a complicated and diversified food web. Since the tropical rainforests possess an abundant supply of water and solar energy, they have one of the most developed ecosystems of this planet. Taiga Biome Food Chain Various types of plants form the foundation of food chain in the taiga biome. The main trophic levels in the taiga biome food chain are producers, primary consumers, secondary consumers, tertiary consumers and decomposers. Read on, to know about these taiga biome nutritional levels in detail. Food chain refers to the natural phenomenon observed in an ecological community, wherein one organism is eaten by another member that belongs to a higher trophic level (nutritional level). As the term goes, taiga biome food chain represents the flow of food energy from one organism to the next organism in the taiga. The dominant plant forms of this terrestrial biome are the conifers, which are characterized by evergreen foliage and cone-­‐shaped canopy. Let's try to understand about food chain in taiga biome. Food Chain in Taiga Biome The interdependency of plants and animals in the taiga biome for food energy is very interesting to learn about. After all, it is the largest of all terrestrial biomes on earth. So, where is the taiga biome located? It is situated in the northernmost region of the northern hemisphere close to the Arctic circle, where winters are extremely cold and long, and summers are warm and short. Taking this into consideration, the taiga is also known as the boreal forest. The trophic levels in the taiga biome food chain, starting from the lowest to the highest, are described below. Producers (Autotrophs) All the green plants having chlorophyll pigments are called producers. Categorized under the first trophic level in the food chain, they produce organic nutrient (glucose) by making use of inorganic sources (sunlight, water and carbon dioxide) through photosynthesis. The producers identified from the taiga biome are many, of which some common examples include fern, moss, jack pine, black spruce, white spruce and balsam fir. Primary Consumers (Herbivores) The organisms that constitute second trophic level are strictly herbivores, i.e. they feed on the green plants and their parts (leaves, roots, flowers and fruits) for deriving energy. Thus, they are exclusive plant eaters. Examples of primary consumers in the food chain of taiga biome are insects, birds, mice, rats, chipmunks, squirrels, porcupines, deer, moose and elk. Secondary Consumers (Carnivores) These are heterotrophs and consume the herbivores for deriving their nutrients. In short, secondary consumers are heterotrophs that rely on organisms of the second trophic level. Thus, secondary consumers are the meat-­‐eaters, which belong to the third trophic level in the food chain. Common examples of secondary consumers in the taiga biome food chain are tarantula, scorpion, snake, some lizards, skunk and weasel. Tertiary Consumers (Carnivores) This trophic level comprises carnivorous animals, which depend on other heterotrophs for food. But, the prime difference between the secondary and tertiary consumers is the type of foods they feed on. Yes, tertiary consumers prey on the secondary consumers, thus occupying a higher trophic level in the taiga biome food chain. Animals falling in this group are lynx, hawk, fox and wolf. Decomposers (Saprotrophs) The decomposing organisms or the saprotrophs fall in the last trophic level. Though they are not commonly talked about in the food chain, the role of these organisms is crucial for overall functioning of the taiga biome. What these living entities do is, break down the complex organic matter of dead organisms, feed on them and also, make the nutrients available for the producers. Examples are some fungi species and bacteria. Taiga Biome Food Chain After going through the trophic levels in the food chain of taiga biome, it becomes easier to understand the channel through which food energy is passed from one organism to the next. The omnivores (e.g. raccoons and bears) are not mentioned clearly in the nutritional levels, but they are heterotrophs and belong to the secondary consumers. A certain amount of energy is converted into biomass, when it gets transferred between two successive trophic levels. Example # 1 Plant → Moose → Wolf Example # 2 Plant → Insect → Tarantula → Owl Example # 3 Plant → Chipmunk → Snake → Hawk Example # 4 Plant → Insect → Squirrel → Fox → Lynx Irrespective of the biome, or type of ecological community, the energy transfer in a food chain takes places from the autotrophic plants to the herbivores, which are then consumed by the carnivores. It is obvious that a heterotroph feeds on many organisms, and there are many predators for a single organism. An interconnected network of these food chains is known as the food web. It is similar to the food chain, except that energy transfer between organisms is multidirectional, or it takes place through different ways.