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Solution
The correct option is B
False
- In a symbiotic relationship, both organisms benefit from each other.
- One such example is the relationship between leguminous plants and Rhizobium.
- Rhizobium grows in the root nodules of the leguminous plant and can convert the atmospheric nitrogen into soluble forms so that it can be absorbed by plants.
- And in return, the root nodules in which the bacteria are present provides them with shelter and food.
A commensal shrimp sits on another sea organism, a sea slug. As a commensal shrimp, it neither brings a benefit nor has a negative effect on its host. Symbiosis is a close relationship between two species in which at least one species benefits. For the other species, the
relationship may be positive, negative, or neutral. There are three basic types of symbiosis: mutualism, commensalism, and parasitism. Mutualism is a symbiotic relationship in which both species benefit. An example of mutualism involves goby fish and shrimp (see Figure
below). The nearly blind shrimp and the fish spend most of their time together. The shrimp maintains a burrow in the sand in which both the fish and shrimp live. When a predator comes near, the fish touches the shrimp with its tail as a warning. Then, both fish and shrimp retreat to the burrow until the predator is gone. From their
relationship, the shrimp gets a warning of approaching danger. The fish gets a safe retreat and a place to lay its eggs.
The multicolored shrimp in the front and the green goby fish behind it have a mutualistic relationship. Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. One species typically uses the other for a purpose other than food. For example,
mites attach themselves to larger flying insects to get a “free ride.” Hermit crabs use the shells of dead snails for homes. Parasitism is a symbiotic relationship in which one species (the parasite) benefits while the other species (the host) is harmed. Many species of
animals are parasites, at least during some stage of their life. Most species are also hosts to one or more parasites. Some parasites live on the surface of their host. Others live inside their host. They may enter the host through a break in the skin or in food or water. For example, roundworms are parasites of mammals, including humans, cats, and dogs (see
Figure below). The worms produce huge numbers of eggs, which are passed in the host’s feces to the environment. Other individuals may be infected by swallowing the eggs in contaminated food or water.Do interactions between species always result
in harm?
Symbiotic Relationships
Mutualism
Commensalism
Parasitism
Roundworms like this one might eventually fill a dog’s intestine unless it gets medical treatment.
Some parasites kill their host, but most do not. It’s easy to see why. If a parasite kills its host, the parasite is also likely to die. Instead, parasites usually cause relatively minor damage to their host.
Summary
- Symbiosis is a close relationship between two species in which at least one species benefits.
- Mutualism is a symbiotic relationship in which both species benefit.
- Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected.
- Parasitism is a symbiotic relationship in which one species (the parasite) benefits while the other species (the host) is harmed.
Review
- Define mutualism and commensalism.
- Give examples of mutualism.
- Explain why most parasites do not kill their host. Why is it in their own best interest to keep their host alive?
Roundworms like this one might eventually fill a dog’s intestine unless it gets medical treatment.
Some parasites kill their host, but most do not. It’s easy to see why. If a parasite kills its host, the parasite is also likely to die. Instead, parasites usually cause relatively minor damage to their host.