Competition occurs when two or more species utilize the same resources, such as food, water, or territory, and their utilization negatively impacts the survival, growth, or reproduction of each other.

Mutualism is a symbiotic relationship where both species benefit from each other. In the case of mistletoe and oak tree, the mistletoe obtains nutrients and support from the oak tree, while the oak tree benefits from the mistletoe's ability to fix nitrogen, which enriches the soil.

Commensalism is a symbiotic relationship where one species benefits from the association with another species without affecting the latter. For example, epiphytic plants growing on trees benefit from the support and access to sunlight, while the trees are unaffected.

Parasitism is a symbiotic relationship where one species (the parasite) benefits from the association with another species (the host) at the expense of the host. Parasites obtain nutrients or other resources from their hosts, often causing harm or even death to the host.

Predation is a type of species interaction where one species (the predator) captures and consumes another species (the prey) for sustenance. Predators play a crucial role in controlling prey populations and maintaining ecological balance.

A keystone species is a species that has a disproportionately large impact on its ecosystem relative to its abundance. Sea otters are considered keystone species because their predation on sea urchins helps maintain kelp forests, which provide habitat and food for various marine organisms.

Mutualism is a symbiotic relationship where both species involved derive benefits from the association. Examples include pollination, where plants benefit from seed dispersal by animals, and animals benefit from the nectar or pollen provided by plants.

Facultative mutualism is a type of mutualistic relationship where the association is beneficial but not essential for the survival of either species. Clownfish and sea anemones form a facultative mutualism, where the clownfish gains protection from predators within the anemone's tentacles, while the anemone benefits from the clownfish's ability to attract prey.

Parasitism is a symbiotic relationship where one species (the parasite) benefits from the association with another species (the host) at the expense of the host. Parasites obtain nutrients or other resources from their hosts, often causing harm or even death to the host.

Obligate mutualism is a type of mutualistic relationship where the association is essential for the survival of both species. Lichens, which are symbiotic associations between fungi and algae, are an example of obligate mutualism, as both the fungus and the alga depend on each other for survival.

Commensalism is a symbiotic relationship where one species benefits from the association with another species without affecting the latter. For example, epiphytic plants growing on trees benefit from the support and access to sunlight, while the trees are unaffected.

A keystone predator is a predator species that has a disproportionately large impact on its ecosystem relative to its abundance. Sea otters are considered keystone predators because their predation on sea urchins helps maintain kelp forests, which provide habitat and food for various marine organisms.

Parasitism is a symbiotic relationship where one species (the parasite) benefits from the association with another species (the host) at the expense of the host. Parasites obtain nutrients or other resources from their hosts, often causing harm or even death to the host.

Obligate mutualism is a type of mutualistic relationship where the association is essential for the survival of both species. Lichens, which are symbiotic associations between fungi and algae, are an example of obligate mutualism, as both the fungus and the alga depend on each other for survival.