Symbiosis

What is symbiosis?

Meaning ‘‘Living together’’ and describes a close, long-term biological interaction between two different organisms.

3 main types of symbiosis

• Mutualism (+/+)

• Commensalism (+/0)

• Parasitism (+/-)

What is mutualism? (+/+)

Both species benefit from the interaction

What is Commensalism? (+/0)

One species benefits. while the other is completely unnafected (Neither helped nor harmed)

What is Parasitism? (+/-)

One species (the parasite) benefits at the expense of the other (the host), which is harmed but usually not killed immediately.

What are the two structural classifications?

• Ectosymbiosis

• Endosymbiosis

What is the meaning of Ectosymbiosis?

The symbiont lives on the outer surface of the host

What is the meaning of Endosybiosis?

The symbiont lives inside the cells or body of the host

Meaning of Symbiont

An organism that lives in close, long-term association with another organism of a different species, known as the host

What are the two dependency levels?

• Obligate Symbiosis

• Facultative Symbiosis

What is Obligate Symbiosis?

The organisms must live together to survive. They cannot live independently

What is Facultative Symbiosis?

The organisms choose to live together for mutual benefit but can live on their own if necessary.

Why does Symbiosis matter?

• Evolution = Symbiotic relationships drive co-evolution and adaptation between species

• Ecosystems = They help species survive harsh conditions, build reefs, and cycle vital nutrients through the soil (like nitrogen)