Final answer:
Fungi differ from plants in that they are heterotrophs without chloroplasts that absorb nutrients rather than photosynthesize. Their cell walls are made of chitin, not cellulose, and they do not have vascular structures like xylem and phloem. Fungi also play a unique role in ecosystems as decomposers.
Step-by-step explanation:
The characteristics that distinguish fungi from plants are fundamental differences in cellular structure, metabolism, and lifestyle. First and foremost, unlike plants, fungi are heterotrophs, meaning they cannot synthesize their food through photosynthesis because they lack chloroplasts and chlorophyll. Instead, they absorb nutrients from their environment. This is one of the key traits that makes them more similar to animals than plants.
Furthermore, the cell walls of fungi are made of chitin, a tough carbohydrate also found in the exoskeletons of insects and other arthropods, unlike plant cell walls which are primarily composed of cellulose. This structural difference is significant and reflective of their separate evolutionary paths. In addition to cellular differences, fungi lack plant-like structures such as xylem and phloem, which are responsible for the transportation of water and nutrients in plants.
Sexually, fungi also have unique features distinguishing them from the familiar sexual mechanisms found in most plants and animals. While some fungi may appear plant-like, with structures such as stems and a root-like mycelium, molecular biology has shown that they are more closely related to animals than plants.
In terms of their ecological role, fungi serve as crucial decomposers, breaking down organic material and recycling nutrients back into the ecosystem, much like bacteria. These characteristics, along with others, clearly set fungi apart from the plant kingdom.