Courses : Forest Ecology Lecturer :Frischa Adellia Semester : 4thSemester, 2022/2023 Session Definition of Symbiosis Symbiosis is a relationship between two organisms of different species that live together in a long-term interaction. In symbiosis, the two organisms usually depend on each other and benefit from the interaction. Symbiosis can take various forms, ranging from a mutualistic relationship where both organisms benefit, to a parasitic relationship where one organism benefits while the other is harmed. Examples are the symbiotic relationship between plants and rhizobia bacteria in forming legume root nodules that fix atmospheric nitrogen, or the mutualistic relationship between algae and coral animals on coral reefs, where the algae provide food through photosynthesis and the coral animals provide shelter and nutrition. Symbiosis can be seen as cooperation between organisms of different species to mutually support their survival. These relationships can vary widely in terms of the nature and benefits provided by each party. Some common forms of symbiosis include: 1. Mutualism: Here, both organisms benefit from the interaction. An example is the relationship between legumes and rhizobia bacteria in plant roots that help obtain nitrogen and carbohydrates. 2. Parasitism: In this relationship, one organism (the parasite) benefits while the other organism (the host) is harmed. For example, parasites such as fleas absorb nutrients from their host's body. 3. Commensalism: Here, one organism benefits while the other organism is unaffected. An example is insectivorous birds that follow grazing animals to obtain insects that fly while their meat is fried. Each form of symbiosis has a different role in the ecosystem and helps maintain natural balance and the survival of the organisms involved. The benefits of symbiosis between two organisms can vary greatly depending on the type of symbiotic relationship formed. Here are some general benefits of symbiosis: 1. Survival: Symbiosis often helps the organisms involved to survive in environments that may be difficult or inhospitable. For example, the mutualistic relationship between plants and rhizobia bacteria helps plants to obtain the nitrogen necessary for growth in nutrientpoor soil. 2. Increased nutrient availability: Some symbiotic relationships can increase nutrient availability for the organisms involved. An example is the mutualistic relationship between algae and coral animals on coral reefs, where the algae provide organic substances resulting from photosynthesis that can be used by coral animals. 3. Protection: Symbiosis can also provide protection to the organisms involved. For example, the mutualistic relationship between ants and thorny plants allows the plants to be protected from plant eaters. 4. Increased sustainability: In some cases, symbiosis can improve the sustainability of ecosystems and the environment. For example, mutualistic relationships between plants and mycorrhizal fungi help improve soil health and plant growth, which in turn strengthens the ecosystem. 5. Ecological efficiency: Some forms of symbiosis can increase ecological efficiency by utilizing available resources more effectively. An example is the mutualistic relationship between herbivorous animals and the bacteria in their digestive systems, which aid in the digestion of plant fiber. Thus, symbiosis provides a variety of benefits for the organisms involved, playing an important role in maintaining the balance of ecosystems and the survival of many species on the planet. Losses in symbiosis can occur primarily in the organism that is the host in the relationship. Some disadvantages of symbiosis between organisms include: 1. Uncontrolled breeding: In some cases, symbiont organisms can reproduce uncontrollably and cause negative impacts on their hosts. For example, parasites infecting host organisms can lead to reduced health and productivity. 2. Competition : Sometimes, symbiont organisms compete with host organisms for certain resources, such as nutrients or living space. This can reduce the well-being and survival of the host organism. 3. Dependency: The host in a symbiosis can become too dependent on the symbiont organism for its survival. If the symbiont is disturbed or lost, the host organism can experience significant negative impacts. 4. Disease and infection: Some symbiotic relationships, particularly parasitism, can leave the host organism susceptible to disease or infection. Parasites, for example, can damage body tissue or compromise the host organism's immune system. 5. Resource losses: In some cases, the host organism may have to allocate significant resources to support the symbiont organism, which may reduce the resources available for the host organism's own growth and reproduction. It is important to remember that losses in symbiosis do not always occur, and many symbiotic relationships work well and are mutually beneficial for both parties. However, understanding the potential risks and negative impacts of symbiosis is also important in the context of ecology and ecosystem balance.