Can You Identify The Trophic Levels At Which These Animals Feed?

Life on the Nutrient Chain

Have y'all ever wondered why we tin can't seem to feed the world's hungry? It's a complex effect, but information technology might surprise you to acquire that it's non because there isn't enough food; current agronomical chapters, based on current engineering science, exists to feed as many every bit 10 billion people. The Earth's population is "merely" about 7 billion. The big question really is: If we desire to feed everyone, what would everyone demand to eat? To answer that question, download this excel spreadsheet and try plugging in some numbers.

Example: I acre of a grain crop could exist used to feed cattle, and so the cattle could be used to feed people. If l% of the energy is lost to the cattle, you could feed twice every bit many people if you fed them the grain directly. Another manner of looking at it is that it would merely have a half acre of land to feed the people grain, simply a whole acre if y'all feed the grain to the cattle and the cattle to the people. A mutual practise to grow cattle faster is to feed them basis upwardly animal protein. This ways that when we eat the meat from the cow, we're at the tertiary level or higher. The loss of energy between trophic levels may also be fifty-fifty higher. Contempo studies suggest that only ~10% of energy is converted to biomass from one trophic level to the next!

The Food Chain: The answer has to do with trophic levels. As you probably know, the organisms at the base of the food chain are photosynthetic; plants on land and phytoplankton (algae) in the oceans. These organisms are called the producers, and they get their energy directly from sunlight and inorganic nutrients. The organisms that eat the producers are the master consumers. They tend to exist modest in size and in that location are many of them. The main consumers are herbivores (vegetarians). The organisms that eat the primary consumers are meat eaters (carnivores) and are called the secondary consumers. The secondary consumers tend to exist larger and fewer in number. This continues on, all the way up to the top of the food chain. About 50% of the energy (peradventure as much as 90%) in food is lost at each trophic level when an organism is eaten, so it is less efficient to exist a higher club consumer than a master consumer. Therefore, the energy transfer from i trophic level to the next, up the food concatenation, is like a pyramid; wider at the base and narrower at the top. Because of this inefficiency, there is only enough food for a few top level consumers, but in that location is lots of nutrient for herbivores lower downward on the food chain. There are fewer consumers than producers.

State and aquatic energy pyramids

Trophic Level	Desert Biome	Grassland Biome	Swimming Biome	Ocean Biome
Producer (Photosynthetic)	Cactus	Grass	Algae	Phytoplankton
Primary Consumer (Herbivore)	Butterfly	Grasshopper	Insect Larva	Zooplankton
Secondary Consumer (Carnivore)	Lizard	Mouse	Minnow	Fish
3rd Consumer (Carnivore)	Serpent	Snake	Frog	Seal
Quaternary Consumer (Carnivore)	Roadrunner	Militarist	Raccoon	Shark

Food Web: At each trophic level, there may be many more species than indicated in the table higher up. Food webs can be very complex. Food availability may vary seasonally or by time of day. An organism like a mouse might play two roles, eating insects on occasion (making it a secondary consumer), but as well dining directly on plants (making it a primary consumer). A food web of who eats who in the southwest American desert biome might look something similar this:

food web

image source: http://iqa.evergreenps.org/scientific discipline/biology/ecosystem_files/food-web.jpg

Keystone Species: In some food webs, there is i critical "keystone species" upon which the unabridged organization depends. In the aforementioned manner that an arch collapses when the keystone is removed, an entire food chain can collapse if there is a pass up in a keystone species. Oft, the keystone species is a predator that keeps the herbivores in check, and prevents them from overconsuming the plants, leading to a massive dice off. When nosotros remove meridian predators like grizzly bears, orca whales, or wolves, for example, there is evidence that it affects non just the prey species, but even the physical environment.

Apex Predators: These species are at the tiptop of the food chain and the healthy adults have no natural predators. The young and onetime may in some cases be preyed upon, simply they typically succumb to disease, hunger, the furnishings of crumbling, or some combination of them. The also suffer from contest with humans, who frequently eliminate the peak predators in order to accept sectional access to the prey species, or through habitat destruction, which is an indirect form of competition.

Decomposers: When organisms die, they are sometimes eaten by scavengers but the remaining tissues are broken downwards past fungi and leaner. In this way, the nutrients that were part of the body are returned to the bottom of the trophic pyramid.

Bioaccumulation: In addition to being less energy efficient, eating higher upward the food concatenation has its risks. Pesticides and heavy metals similar mercury, arsenic, and atomic number 82 tend to be consumed in small quantities past the primary consumers. These toxins go stored in the fats of the animal. When this animal is eaten by a secondary consumer, these toxins become more full-bodied because secondary consumers eat lots of principal consumers, and often live longer too. Swordfish and tuna are nigh the top of the aquatic nutrient concatenation and, when nosotros swallow them, we are consuming all of the toxins that they take accumulated over a lifetime. For this reason, pregnant women are advised against eating these foods.

Solve the following issues mathematically.

1. Given: 10 billion people tin be fed a basic vegetarian nutrition that is nutritionally complete. How many people could we feed at the American standard-a third level of consumption (3rd order consumers?). 50% of the energy is lost by each college level.

2. If there are 250 million people in the United States most of them eating at the Third (3rd) level of consumption, how many people could we feed at the Chief level?

3. Some animals like sharks are fifth order consumers! Sharks eat tuna that eat mackerel that consume herring that eat copepods that eat diatoms. If we were to make the reasonable assumption that each of these animals eats 2 of its prey each twenty-four hours, how many organisms died to feed the shark in one day?

Source: https://www2.nau.edu/lrm22/lessons/food_chain/food_chain.html

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