Energy flow (ecology)

Plants get energy from the sun.

They use sunlight to make food. This helps them grow.

Next, animals eat the plants. This gives the animals energy too. This is how energy moves.

Some animals eat other animals. This moves energy even higher. Some energy is lost as heat. This happens at every step.

Energy flows in one direction. It goes from the sun to plants. Then it goes to animals.

Nature uses this energy to live. It is a great cycle.

Energy moves through living things in a set of steps.

This is called energy flow. It starts with producers. Producers are living things like plants and algae. They use photosynthesis to make food. This means they turn sunlight into a sugar called glucose.

This sugar gives them power to grow.

Next come the consumers. These are animals that eat plants or other animals. Energy moves from the producer to the consumer. This move is one-way. It does not go backward. At each step, some energy is lost as heat. This is why there are fewer top hunters than there are plants.

Most energy moves in small amounts. Only about 10% of energy reaches the next level. This creates a shape called a trophic pyramid. Some plants are very special. Carnivorous plants live where nutrients are low. They catch insects to get what they need. The Venus flytrap uses a snap trap to catch its food.

This helps them survive in many places.

Energy flows through living things in a special way. This movement is called energy flow. It happens inside an ecosystem, which is a community of living things. All life can be sorted into two groups: producers and consumers. Producers are living things like plants, algae, and mosses. They use photosynthesis to make food. This means they turn sunlight, water, and carbon dioxide into oxygen and a sugar called glucose.

This glucose provides stored energy for the plant. Consumers are living things that must eat to get their energy. They can eat producers or other consumers.

Energy moves in a specific way through a food chain. Each step in the chain is called a trophic level. We can use arrows to show which way the energy moves. These arrows always point in one direction. Energy does not flow backward in a food chain. As energy moves from one level to the next, some of it is lost as heat. This happens because organisms use energy for cellular respiration to stay alive. Because energy is lost at every step, there is much less energy at the top. This is why there are fewer top hunters than there are plants.

Scientists use a model called a trophic pyramid to show how much life exists at each level. This pyramid helps us see how much energy makes it to the next step. In general, only about 10% of energy moves from producers to primary consumers. Then, only 10% of that amount moves to the next level. This is known as ecological efficiency. This efficiency can change from 5% to 20% depending on the ecosystem.

Some organisms, like chemosynthetic bacteria, do things differently. They live deep in the ocean near hydrothermal vents. Instead of sunlight, they use energy from chemicals like hydrogen sulfide to make glucose. This process is called chemosynthesis.

Some plants have found clever ways to get nutrients. In places where the soil is poor, plants may become carnivorous. These plants get nutrients like nitrogen by eating insects. For example, a pitcher plant uses a pitfall trap to lure insects into a bulb shape. A Venus flytrap uses a snap trap to catch its prey.

There are also flypaper traps that use sticky liquid. These plants can live almost anywhere in the world, except for the Arctic and Antarctica. They are amazing examples of how life adapts to hard jobs.

Energy also moves through dead material called detritus. Many living things, called detritivores, eat this decaying organic matter. In a temperate forest, about 62% of organic material is made of dead plants. In streams, leaves fall into the water and begin to break down. Microbes and small animals help soften the leaves to make them edible. This cycle is very important for keeping ecosystems healthy.

Whether in water or on land, the flow of energy connects all living things together.

Energy flow is the movement of energy through living things within an ecosystem. This process connects all organisms through a series of transfers and transformations. Scientists organize these living things into groups called producers and consumers. These organisms are further arranged into food chains to show how energy moves. Each step or level in a food chain is known as a trophic level. To visualize the quantity of life at each level, ecologists use trophic pyramids.

Energy flow is a unidirectional process, meaning it moves in only one direction. We represent this direction using arrows in a food chain. The head of an arrow shows where the energy is going. This movement is governed by the laws of thermodynamics. Thermodynamics is the scientific theory regarding how energy is exchanged between systems. In an ecosystem, energy starts externally as solar radiation from the sun. This energy is then transferred and transformed among various organisms.

Primary production is the first major step in this energetic process. Producers are organisms that perform photosynthesis to create food. They take in water and carbon dioxide from the air. Using energy from the sun, they convert these into oxygen and glucose. Glucose is a sugar that serves as a storable, usable form of chemical energy. Most producers, such as algae, mosses, trees, and grasses, rely on sunlight. However, some bacteria use chemosynthesis instead of photosynthesis. These bacteria live near hydrothermal vents deep in the ocean. They use energy from chemicals like hydrogen sulfide to convert carbon dioxide into glucose.

Energy is lost at every single step of the food chain. This loss happens because organisms must perform cellular respiration to survive. During cellular respiration, organisms take in oxygen and sugar to release energy. This process converts the sugar back into carbon dioxide and water. A large portion of energy is lost as heat during this transformation. Because of this loss, ecological efficiency is often quite low. Generally, only about 10% of energy moves from one trophic level to the next. This efficiency can range from 5% to 20% depending on the specific ecosystem.

In terrestrial environments, energy moves through distinct consumer levels. Primary consumers are herbivores that eat the producers. Secondary consumers are carnivores that eat the herbivores. Tertiary consumers are the top predators in the system. Because energy decreases so much at each level, there are fewer tertiary consumers than producers. In these land systems, herbivores have an assimilation efficiency of roughly 20% to 50%. Carnivores are much more efficient, with an assimilation rate of about 80%. The movement of animals, such as immigration or emigration, can also affect energy levels.

Some plants have adapted to survive in environments with very low nutrients. These are known as carnivorous plants. They obtain essential nutrients, like nitrogen, by consuming other organisms. Pitcher plants use a pitfall trap to lure insects into a bulb-shaped body. Once inside, enzymes are secreted to digest the organism. Other plants use a flypaper trap, which uses a sticky liquid to catch insects. The Venus flytrap uses a snap trap that closes when it detects touch.

Energy also flows through detritus, which is decaying organic matter. Detritivores are organisms that consume this decomposing material. In temperate forests, dead plants make up about 62% of the organic material. In stream ecosystems, fallen leaves become coarse particulate organic matter, or CPOM. Microbes and meiofauna colonize this matter to break it down. This process helps soften the leaves so they are more edible for other animals. This detrital food chain is a massive part of secondary production in many environments.