Understand trophic levels and flow of energy - AP Biology

Producers are always the lowest level of a trophic hierarchy, and consist of the autotrophs in the system. Organisms that feed off of producers are considered primary consumers.

In this example, the grasses are the producers. Both the rabbits and the turtles will be primary consumers.

An organism that feeds on primary consumers is considered a secondary consumer.

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.

Biological organization extends from the level of subatomic particles all the way up to the biosphere. Within the fields of molecular and cell biology, the atomic, molecular, and cellular levels of biology are most important. In the fields of physiology and anatomy, organs, organ systems, and organisms feature prominently.

Within ecology and population genetics, the higher levels of organization are most pertinent. Several organisms make up a population, which in turn makes up a community, and then an ecosystem. A group of ecosystems make up a biome, and the sum of all the biomes is a biosphere.

Atmosphere and Earth are not considered levels of biological organization.

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.

Global ecology refers to large-scale interactions between the earth’s ecosystems, atmosphere, landscapes, and seascapes. Landscape ecology refers to the spatial orientation and patterns within specific landscapes or seascapes. Ecosystem ecology observes the interactions, both biotic and abiotic, within a given landscape area. Community ecology is like ecosystem ecology, but applies to communities of organisms. It observes the spatial distribution, abundance, relationships, and interactions between organisms of different species in a given ecosystem. Population ecology refers to the spatial distribution, abundance, relationships, and interactions within the same species in a given community. Organismal ecology studies each organism’s behavior, anatomy, evolution, adaptation, and relative fitness in a given environment.

Variable limiting refers to when an environmental variable that is lacking. If light is lacking, the algae will not grow and reproduce; the environmental variable, light, is limiting the algae’s success. The variable optimum is when the variables are perfectly balanced. Variable inhibiting refers to when when an environmental variable is in abundance, to the point where it is harmful. If there is too much light, the algae will no longer continue growing and reproducing, but will begin too die off. In this situation, light is variable inhibiting.

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.

An ecological niche is the sum of a species’ use of its environment, including both biotic and abiotic factors. Resource partitioning is the differentiation of niches; it is impossible for two species to have the same niche and use the same resources. Resource partitioning allows for differentiation of niches between similar species so they can coexist. A fundamental niche is described in forest B, where moss 2 grows both above and below the shrubbery. It is the niche that could be potentially occupied by a species. The realized niche is the term that refers to the area of moss 2 in forest A. The realized niche is the portion of the fundamental niche that an organism actually occupies. We know that moss 2 can potentially occupy areas above and below shrubbery, but in forest A, it only occupies the area below the shrubbery (its realized niche).

The term “abiotic” refers to the nonliving components of the environment; therefore, a rock would be characterized as an abiotic part of the environment.

Human activities can have negative impacts on the proper functioning of ecosystems and environments. One human activity that has a direct impact on marine environments is overfishing, which may critically change the delicate balance of the ecosystem.