Symbiosis & Mutualism

What is symbiosis in ecology?

Symbiosis is a long-term, close ecological relationship between two different species, where at least one benefits. It includes mutualism, commensalism, and parasitism.

What are the three main types of symbiosis?

• Mutualism: both species benefit.

• Commensalism: one benefits, the other is unaffected.

• Parasitism: one benefits, the other is harmed.

What is mutualism?

Mutualism is a type of symbiosis where both species benefit from the interaction. It often involves food, protection, or reproduction advantages for both partners.

Give a plant–animal example of mutualism.

Flowering plants and pollinators (bees, hummingbirds, bats):

• Plants benefit → pollen transfer → reproduction.

• Pollinators benefit → nectar or fruit for energy.

Give a human example of mutualism.

Gut bacteria in humans:

• Bacteria help break down food (like fibre).

• Humans provide bacteria with nutrients and a safe environment.

Give a marine example of mutualism.

Chemosynthetic bacteria in hydrothermal vent animals (e.g., tube worms):

• Bacteria produce food using chemical energy.

• Animals provide housing and compounds needed for bacterial metabolism.