Food Pyramids and Food Webs - High School Biology

Autotrophs are organisms that are capable of generating biological energy from inorganic sources, such as sunlight in the case of photoautotrophs. Cyanobacteria are thought to be the prokaryotic precursor to chloroplasts through the endosymbiotic theory because they are able to perform photosynthesis. Cyanobacteria are, thus, photoautotrophs. Green algae are another type of photoautotroph.

Heterotrophs use organic materials from the environment to general energy. Animals are heterotrophs, including cows.

Saprotrophs, many of which are fungi, gain nutrients from decaying organic material. Mushrooms are saprotrophs.

Ecology is essentially the study of all the living things on the planet and their relationships with each other. Ecology can be organized into levels: population, community, ecosystem, and biosphere. A population is a group of organisms that belong to the same species, share an area, and can reproduce with each other. A community is composed of the different species that can be found in a geographical location. An ecosystem encompasses all abiotic and biotic factors in an area. The biosphere refers to those parts of the earth that are able to support and sustain life.

Within ecosystems, there is always a transfer of energy, usually from one organism to another. There is also energy transfer between abiotic and biotic factors. The caterpillar and lion are examples of consumers because they are unable to make their own food and must rely on other living organisms for energy. Consumers are subdivided into herbivores, omnivores, and carnivores. Producers are those living things in the ecosystem that generally produce energy using photosynthesis or light. Organisms that break down dead or decaying matter for energy are called decomposers. These are most likely bacteria, fungi (such as mushrooms), and some worms.

A flower in this example is a producer, which means it will make its own energy through photosynthesis. As a result, the flower must be the first element of our chain; food chains will always start with a producer. The caterpillar, frog, and snake are consumers, meaning they will need other organisms for energy.

A producer is an organism that makes its own food from the energy of the sun via photosynthesis. Green algae is a producer; it has chlorophyll pigments and can make glucose via photosynthesis. A frog is a consumer; a worm is a decomposer; a fungus is a saprophyte; a bear is a consumer.

An omnivore eats both plants and animals. Humans are an example of omnivores.

Herbivores only eat plants. Carnivores only eat animals. Detritivores eat decaying matter.

Organisms that eat producers are known as primary consumers. Organisms that eat primary consumers are secondary consumers, and organisms that eat secondary consumers are tertiary consumers and so on. Autotrophs are able to fix their own carbon from the air, converting it into food e.g., glucose, and need not eat other organisms. Predators are animals that eat prey animals, thus they are a type of secondary (or higher) consumer.

Biomagnification is described as the concentration of a pollutant increasing as it moves through the tropic levels of an ecosystem. For example, if a pollutant has a low concentration in a plant, that concentration will be much higher in the animal that eats that plant. This occurs because organisms do not have enzymes that can break down these chemicals. This process does not occur with minerals.

Plants make up the bottom trophic level: the producers. This is because plants produce energy through photosynthesis. They do not have to eat other organisms to obtain energy, they make their own using carbon dioxide, water and sunlight.

Herbivores are plant-eating organisms. They are classified in the primary consumer trophic level. An easy way to remember this is to break down the word. Herbs are types of plants, so when we see “herb” in herbivore think of plants. Carnivores eat other animals. Autotrophs and producers need not eat anything to get energy, rather, they make their own.

Omnivores eat plants and meats. Carnivores eat meat only. Herbivores eat plants only. Detrivores eat dead organisms.

This question requires careful reading of the correct order of an ecosystem on earth. The correct order, from smallest to largest, for an ecosystem is “individual, population, community, ecosystem.” Individual organisms make up populations, which interact with other populations in communities, which in turn belong to ecosystems that have a particular environment, such as desert or rainforest.

The latin name consists of the genus and species of the organism. These are the most specific of the taxonomic classifications. The taxonomic classifications are domain, kingdom, phylum, class, order, family, genus, and species.

In a standard food pyramid, organisms are divided into trophic levels based on their means of gaining nutrients. As one moves upwards through trophic levels, the number of organisms that can be sustained decreases. This is because energy is lost between each level. Typically, about 90% of the energy in one trophic level is lost during transfer to the next highest level; this leaves on about 10% of the energy to be used by the consumer. Because of this disparity, it is very difficult to maintain large populations at higher trophic levels. This explains why lower level organisms can easily flourish (such as ants), while higher level organisms can easily become endangered (such as tigers).

The sun is the source of all energy in an ecosystem. Without the energy from the sun, the plants cannot grow and the animals would not have food to eat. Plants are considered producers, meaning that they are able to convert sunlight into chemical energy. Animals are considered consumers, in that they consume plants or other animals to absorb energy. If you trace back far enough in a food chain, you will always arrive at a producer and, subsequently, the sun.

Living things need water to grow, but it does not directly contribute energy.

The energy in a food pyramid decreases as it is tranferred up the pyramid. The bottom of the pyramid, the producers, start with the most energy. When they are eaten by primary consumers, only about ten percent of the energy is transferred to the next level; the rest is lost. The next level of secondary consumers also only keeps about ten percent of the energy from the level below that—only one percent of the original producer-level energy. This loss of energy continues up to the highest level of the pyramid. The lost energy is released as heat into the atmosphere.

The great white shark is at the top of the food pyramid in its ocean ecosystem. Since it is at the top, it receives the least amount of energy from its food because the amount of energy decreases as one moves up the pyramid.

Green algae contains the pigment chlorophyll, which is responsible for photosynthesis. This makes green algae a producer, and the lowest level of the pyramid. As a result, the green algae will represent the largest amount of energy in the ecosystem. The anchovy eats the algae, the tuna eats the anchovy, the seal eats the tuna, and the shark eats the seal. After each level, approximately 90% of the energy of the pervious level is lost. After four transitions (to get to the level of the shark), only 0.01% of the original producer energy has been transferred to the shark!

Autotrophs are the base part of any food pyramid/web/chain. They take inorganic substances and turn them into organic substances that are later consumed and used by heterotrophs for energy. Most autotrophs absorb carbon dioxide from the atmosphere and minerals/nutrients from the soil in order to feed, reproduce, and grow, drawing their resources from the surrounding inorganic environment.

The sun, while crucial to many autotrophs, provides energy for the processes—however, it does not provide carbon, nutrients, or minerals. Human activity may contribute to the autotrophs' activity, but it is not the main source of the necessary resources.

Autotrophs make their own food, then using cellular metabolism, this food is converted to energy. Examples are plants converting sunlight, carbon dioxide and water into glucose and oxygen (photosynthesis). Then, the plants breakdown glucose, converting this food molecule into the energy molecule ATP via glycolysis, Krebs cycle and electron transport under aerobic conditions, and via fermentation under anaerobic conditions. Heterotrophs, like humans, must ingest organic material (food) in order to meet their energy demands.