The elimination of producers would result in the collapse of the whole food network. Primary consumers or herbivores that graze directly on producers would become extinct. Higher level consumers would suffer as lower trophic level creatures died out. Without their predators to keep them in check, animal populations would increase dramatically, leading to the extinction of many species.
Ecosystems depend upon interactions between organisms at various levels of a food chain or pyramid. At the bottom are plants, which produce seeds and spores that can be ingested by other organisms for food or dispersed by wind or water to start new plants. Above the plants are bacteria and fungi, which live on the surface of plants or within them and play important roles in recycling nutrients. In between are other types of organisms such as insects, which are eaten by birds and other animals. At the top of the pyramid are larger animals like cats, dogs, cows, and elephants, who eat plants and each other when resources are scarce.
When producers are removed from an ecosystem, there are not enough primary consumers left to keep up with their demand for food. Most will go hungry or switch to eating others less fit for survival. The remaining primary consumers will be able to feed themselves but not enough higher level consumers to balance out their diet. The entire food web will collapse.
Producers contribute genes to the next generation via reproduction.
The secondary consumers, or carnivores that devour the main consumers, would be the next to be harmed. Eventually, only top predators would remain because they have no prey to eat.
This is called "trophic extinction". In reality, many species go extinct while others survive - this is called "biodiversity". But if all consumers lost their ability to shift their position in the food chain, then we might start to see more of these mass extinctions happening more often. They could be caused by climate change, disease, or something else entirely. But whatever the cause, when a major predator loses its place at the top of the food chain, then other animals will be able to grow larger and dominate their environment.
However, even these dead species would be depleted, causing the entire food chain to collapse. To summarize, the loss of any trophic level in a food web disrupts the equilibrium and can lead to the web's final collapse.
Decomposers would decompose deceased creatures' corpses, returning their fundamental components and compounds to the environment. This is called secondary decomposition.
Higher level predators that eat primary consumers etc. would also go extinct. The only remaining predators will be tertiary consumers which eat decomposed organisms - invertebrates and fungi. There will be no further levels of predator-prey relationships because there are no more producers to consume.
This is called an "ecological trap" because higher level consumers rely on lower level consumers for survival. If lower level consumers disappear, so will the higher level ones. There would be no one left to destroy the seeds of dead plants so they cannot grow back. Over time, this could lead to a world full of uneaten food that spoils before it can be consumed by anyone.
The only way to stop this from happening is if we cut down all the trees and remove all the other producers such as grasses and other plants. This would allow room for more consumers by killing off the competition.
In reality, ecological traps exist in nature and can cause problems but not necessarily lead to extinction.
What would happen if primary consumers vanished? Producers? If the primary consumers became extinct, there would be nothing to eat for the producers, causing them to overpopulate, and no food for the secondary consumers, causing them to perish. The secondary consumers would be first in line when the food ran out, followed by the tertiary consumers, and so on.
Therefore, without primary consumers to eat their waste, producers would have nothing to eat and would die out themselves. This is called "the consumer's extinction debt."
The main reason why predators are important is because they keep prey populations stable by removing too many animals from the population, thus preventing excessive breeding by older animals who cannot reproduce anymore but can still fight off other animals for food. This is called "self-regulation of predator populations."
Without predators, there would be no self-regulation of animal populations, which would result in some animals being killed by predators every day. This might not seem like a problem now, but it would eventually cause many species to go extinct. Scientists think that this is what happened to the dinosaurs because their only natural predator, humans, evolved enough to build weapons capable of killing them.