Question

Habitats of phycomycetes are (a) Aquatic (b) Decaying wood in moist and damp place (c) Obligate parasite in plant (d) All of these

Short answer

(d) All of these

Step-by-step solution

Understanding Phycomycetes Habitat

Phycomycetes are a group of fungi that can be found in a diverse range of habitats. They are very important decomposers and recyclers of organic matter. This group includes species that are aquatic, living in fresh or marine waters.

Considering Other Options

Next, considering the second option, phycomycetes can indeed be found in decaying wood in moist and damp places. Also, there are members of this group that can act as obligate parasites in plants, meaning they completely depend on their host plant for survival.

Final Decision

Given that they can be found in aquatic habitats, moist wood, and as parasites in plants, it is clear that the correct answer is (d) All of these.

Key concepts

Fungi Decomposers

Fungi serve as one of Earth's most efficient decomposers, playing a critical role in our ecosystem by breaking down dead organic matter and recycling nutrients back into the soil. Among these, the group known as phycomycetes are exceptional recyclers. Phycomycetes contribute significantly to this process by decomposing complex substances, such as lignin and cellulose found in wood, into simpler, usable forms. This decomposition is vital, as it helps to maintain soil health and fertility, which in turn supports plant growth.

Phycomycetes possess enzymes that degrade the tough plant materials, converting them into nutrients that become available for other organisms in the food chain. Without the action of such decomposers, our forests and other terrestrial ecosystems would choke under the weight of undecomposed organic matter, disrupting the balance of nature.

Aquatic Habitats

In aquatic ecosystems, phycomycetes find a home that offers both the moisture necessary for their growth and a plethora of organic materials to decompose. They are commonly found in both fresh and marine waters, acting as a key component of the food web within these environments. By breaking down dead aquatic plants and animals, they release nutrients back into the water, which are then used by algae and other aquatic plants.

Moreover, some phycomycetes form symbiotic relationships with algae, known as lichen, which can be found on rocks or other substrates within an aquatic habitat. This collaboration showcases the adaptability of phycomycetes to various conditions, their importance in nutrient cycling, and their contribution to the biodiversity of aquatic systems.

Obligate Parasites in Plants

Phycomycetes also include species that are obligate parasites, which infest plants and rely exclusively on their host for nutrition. These fungi penetrate plant tissues, sometimes causing diseases. For instance, the water molds or oomycetes, which are often grouped with phycomycetes, are notorious for their role in plant diseases, such as the late blight of potatoes caused by Phytophthora infestans.

As obligate parasites, these fungi have evolved specialized mechanisms to invade and derive nutrients from living plant cells without killing them outright, which would cut off their own supply of nutrients. This parasitic lifestyle implicates significant agricultural and economic impacts, as it can lead to reduced crop yields. Understanding the biology of these organisms is crucial for developing measures to protect crops from these invasive parasites.