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The gallbladder has a capacity of about 50 millilitres (1.8 imperial fluid ounces). [2] The gallbladder is shaped like a pear, with its tip opening into the cystic duct. [4] The gallbladder is divided into three sections: the fundus, body, and neck. The fundus is the rounded base, angled so that it faces the abdominal wall.
Food chain in a Swedish lake. Osprey feed on northern pike, which in turn feed on perch which eat bleak which eat crustaceans.. A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as earthworms and woodlice ...
Plant-animal interactions are important pathways for the transfer of energy within ecosystems, where both advantageous and unfavorable interactions support ecosystem health. [ 1 ] [ 2 ] Plant-animal interactions can take on important ecological functions and manifest in a variety of combinations of favorable and unfavorable associations, for ...
Out of a total of 28,400 terawatt-hours (96.8 × 10 ^ 15 BTU) of energy used in the US in 1999, 10.5% was used in food production, [3] with the percentage accounting for food from both producer and primary consumer trophic levels. In comparing the cultivation of animals versus plants, there is a clear difference in magnitude of energy efficiency.
The mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web. [42] [14] In a simple predator-prey example, a deer is one step removed from the plants it eats (chain length = 1) and a wolf that eats the deer is two steps removed from the plants (chain length = 2).
This reliance underscores the critical role of native plants in supporting ecological food chains. The distinction between generalists and specialists is not limited to animals. For example, some plants require a narrow range of temperatures, soil conditions and precipitation to survive while others can tolerate a broader range of conditions.
An example of a topological food web (image courtesy of USDA) [1] The soil food web is the community of organisms living all or part of their lives in the soil. It describes a complex living system in the soil and how it interacts with the environment, plants, and animals. Food webs describe the transfer of energy between species in an ecosystem.
Ecological pyramids begin with producers on the bottom (such as plants) and proceed through the various trophic levels (such as herbivores that eat plants, then carnivores that eat flesh, then omnivores that eat both plants and flesh, and so on). The highest level is the top of the food chain. Biomass can be measured by a bomb calorimeter.