Question

A lichen is a symbiotic organism. It appears similar to a plant, but it is actually made up of two separate organisms, a fungus and cyanobacteria. The fungus transports water and nutrients to the cyanobacteria which then stores glucose for use by the fungus. Using a plant as your reference, which of the following statements would be the most accurate comparison to help someone understand the relationship between the fungus and cyanobacteria?

Answer 1

Lichens are a symbiotic relationship between a fungus and either a green alga or a cyanobacterium, with both organisms benefiting in a way similar to the mutualistic relationship between mycorrhizal fungi and plants. The fungus provides structure and absorbs water and nutrients, whereas the alga or cyanobacterium produces carbohydrates through photosynthesis.

Step-by-step explanation:

Understanding the symbiotic relationship between the fungus and cyanobacteria in lichens can be compared to the relationship between a plant and its environment. Lichens are a combination of two organisms, a fungus and either a green alga or cyanobacterium, which is in a symbiotic relationship where both organisms benefit. Similar to how plants use sunlight to make food through photosynthesis, the cyanobacteria or green alga in a lichen produces carbohydrates that the fungus uses. In turn, the fungus provides a structure, absorbs water and nutrients from the environment, and offers protection, much like a plant's roots stabilize the plant and take up water and nutrients from the soil. While lichens are often seen as a type of mutualism, where both organisms benefit, some scientists suggest the relationship may also have aspects of controlled parasitism, with the fungus potentially restricting the growth of the cyanobacteria or alga to some degree.

Mycorrhiza is another example of a symbiotic relationship, this time between a fungus and a plant, where the fungus helps the plant absorb water and nutrients while the plant provides food made via photosynthesis. This mutually advantageous relationship is what likely enabled plants to first colonize land.

In conclusion, although lichens resemble plants, they are actually a complex partnership between a fungus and a photosynthetic organism, working together to survive in environments that would challenge either organism on its own.

Answer 2

A good comparison to help someone understand the relationship between the fungus and cyanobacteria in a lichen would be to the relationship between the roots and leaves of a plant. The roots absorb water and minerals from the soil and transport them to the leaves, which then use the nutrients to produce glucose through photosynthesis. In the same way, the fungus in a lichen transports water and nutrients to the cyanobacteria, which then stores glucose for use by the fungus. Just as the roots and leaves of a plant depend on each other for survival, the fungus and cyanobacteria in a lichen have a symbiotic relationship in which they both benefit