Symbiosis: Endo, Ecto, Mutualism, Commensalism, Parasitism

• Symbiosis is any relationship or interaction between two different species where at least one organism benefits.

Endo vs Ecto Symbiosis

• Endosymbiosis occurs when a smaller organism lives within a host organism's cells, tissues, or other internal structures.
• Termites rely on microorganisms living in their gut to properly digest wood, an example of endosymbiosis.
• Ectosymbiosis is a symbiotic relationship where one organism lives on the surface of another.
• Barnacles on humpback whales are an example of ectosymbiosis.
• European mistletoe is an ectosymbiotic parasite.
• It lives on trees and extracts nutrients and water.

Types of Symbiotic Relationships

• Symbiotic relationships are defined by how they affect both organisms involved.
• Mutualism: both organisms benefit.
• Commensalism: one organism benefits, the other is neutral.
• Parasitism: one organism benefits, the other is harmed.

Mutualism

• Mutualism involves a symbiotic relationship where both organisms benefit by providing resources such as food, shelter, locomotion, or protection to each other.

Commensalism

• Commensalism is a symbiotic relationship where one organism benefits, and the other is neither helped nor harmed.
• The benefitting organism might obtain resources like food, shelter, locomotion, or protection, but without significantly impacting the other organism.

Parasitism

• Parasitism is a symbiotic relationship where one organism benefits while the other is harmed.
• The parasite might live with, on, or in a host organism.
• It's often in the parasite's best interest not to kill the host, but it can still happen.

Symbiotic Relationship Examples

Mutualism

• Pistol Shrimp and Goby:
• Both species live in sandy burrows on the sea floor.
• The shrimp digs and maintains a burrow, while the goby protects the shrimp and the burrow.
• They share the burrow, guarding its entrance at different times.
• The goby alerts the shrimp to danger by flipping its fin against the shrimp's antennae.
• Nile Crocodile and Egyptian Plover:
• The Nile crocodile sits with its mouth open to allow the Egyptian plover to pick food out of its teeth.
• This prevents rotting and provides food for the plover.
• Clownfish and Sea Anemone:
• The clownfish lives in the sea anemone, eating leftover food and keeping it clean.
• The anemone's tentacles protect the clownfish from predators.

Commensalism

• Cattle Egrets and Cows:
• Cattle egrets catch and consume insects stirred up by grazing cows.
• The cows are not affected by the egrets' presence.
• Imperial Shrimp and Sea Cucumber:
• Imperial shrimp catch a ride on sea cucumbers or sea slugs to travel to feeding areas.
• The sea cucumber is not bothered by the presence of the shrimp.
• Shark and Remora Fish:
• The remora attaches itself to the shark, gaining transportation, protection, and food scraps.

Parasitism

• Cymothoa exigua and a Fish:
• The isopod enters a fish's gills, attaches to the base of the tongue, and sucks blood.
• The tongue withers and dies, and the isopod replaces it, acting as a living prosthetic.
• The isopod continues to suck blood and steal food, depriving the fish of nutrients.
• Braconid Wasps and the Tomato Hornworm:
• The wasp lays its eggs inside the hornworm caterpillar.
• As the wasps hatch, they feed on the caterpillar's insides.
• The wasps spin cocoons on the caterpillar's back and mature into adult wasps.
• Eventually, the caterpillar dies as its insides are consumed.
• Tapeworms and Infected Organisms:
• Tapeworms attach to the inside of the intestines of larger organisms.
• They get their food by eating the host's partially digested food or depriving them of nutrients.

Mutualism vs Commensalism

• Mutualism: Both species benefit (Species A = +, Species B = +).
• Example: Bees and Flowers: Flowers get pollinated while the bee gets nectar.
• Commensalism: One species benefits, the other is neither helped nor harmed (Species A = +, Species B = 0).
• Example: Whale and Barnacles: The barnacle gets food while attached to the whale; the whale is unaffected.

Explore symbiosis: endosymbiosis (organism inside host), ectosymbiosis (organism on host's surface). Discover mutualism (both benefit), commensalism (one benefits, other is neutral), and parasitism (one benefits, other harmed). Examples include termites, barnacles, and mistletoe.