Organisms interact with each other in the natural world. Animals can interact with other animals. Plants can interact with other plants. Animals and plants are often enemies! Many animals depend on plants for food. Many plants also don't want to be eaten.
While many plants are not anti-pest, they have a way of dealing with unwanted visitors. Carnivorous plants lure insects to them with bright colours and sweet nectar. This plant, the sundew, has balls of sweet syrup that insects want to eat. Unfortunately for the insects, these droplets are also extremely sticky. Any insects that come to rest on the sundew will find themselves stuck and absorbed by this devious plant.
Some symbiosis relationships can occur inside the tissue of another organism. For example, there are bacteria that live in root nodules on legume roots. The bacteria in the roots can turn nitrogen into ammonia. Ammonia is important, because it is used in other processes that allow the plant to grow and survive.
Other plants and animals also have relationships that are symbiotic. Mutualism is a kind of symbiosis. This is when both organisms are able to benefit from the relationship or interaction. For example, many plant-eating animals have gut flora to help them digest plants. Plant matter can be difficult to digest without the help of bacteria. The gut flora is bacteria living in the animals' intestines.
Most flowering plants need pollinators to help them pollinate. Pollination is the process by which plants are fertilized. Without this process, they would not be able to make seeds and reproduce. Plants rely on insects like bees to spread their pollen.
Mutualism also can be seen with lichen. Lichen is a combination of fungi and algae. The algae have chlorophyll, which allows them to use sunlight to make their own food. Fungi can feed on dead organisms and absorb nutrients. The fungi also anchor the lichen.
When plants need to spread their seeds, many of them have colourful and sweet fruits. The animals eat these delicious treats. But the relationship works both ways. The animals help the plants by dispersing the seeds in the fruit. After animals digest their food, their poo contains all the seeds inside. This way, the new plants can grow safely away from the parent plant.
Symbiosis isn't limited to plants and animals. One organism could benefit, while the other isn't affected at all. This is called commensalism.
The remora fish uses the sucker on the top of its head to attach itself to the tiger shark. The small fish gets a free ride and even a meal; it feeds on the scraps leftover from the shark's prey. The remora does not affect the shark, and does not do anything to benefit the shark.
Many parasitism relationships are obligatory. Parasitism is not an equal relationship. It happens when one organism benefits while harming the other. One animal gains at the expense of the other. Predator and prey relationships are all parasitic in nature.
Ticks are some of the biggest pests to large land animals. The zebra, giraffe, rhino, and buffalo in Africa are all constantly harassed by ticks. These insects burrow into the skin of their larger hosts and suck their blood. They are a constant annoyance to many large mammals.
The relationship between plants and animals has helped sustain many of the ecosystems on our planet. When a part of that ecosystem is out of balance, everything inside is threatened. Plants and animals rely on each other, and all of them rely on humans to take care of the planet!