Mold is a common type of fungus that thrives in moist, warm conditions. It is an important part of our ecosystem and yet can be a nuisance. Learn more about this organism and quiz yourself at the end.
Definition of Mold
Have you ever experienced that moment of horror when you open a sour cream container in your fridge, only to find a patch of gray fuzz resting contentedly on top? If you’re like most people, your reactions to this discovery were probably unpleasant. In fact, they were probably along the lines of gross. Most of us don’t appreciate finding mold in our refrigerators and bread bags. But what is this hairy organism? And why is it crucial to the survival of an ecosystem? In this lesson, we will learn more about mold and how it functions in our world.
Mold is a living organism that belongs to the kingdom Fungi. Fungi are unique in that although some appear plant-like, they are neither plant nor animal. Mold is heterotrophic, meaning it cannot make its own food like plants do. Mold must gain nutrients from other organic substances.
Unlike animals, however, mold does not really ‘eat’ its food. It must absorb nutrition from other organisms. To do this, mold secretes enzymes that break down the food substance into smaller organic molecules that can then be absorbed. If you’ve ever grabbed a piece of moldy fruit, you may have felt the soft and mushy area that has essentially been digested.Mold is composed of thread-like filaments called hyphae. The hyphae then form a conglomerate, which is called a mycelium. You can think of this as like a grassy lawn.
Much like individual blades of grass make up a lawn, many hyphae make up a mycelium. This explains its ‘hairy’ appearance.Although mold itself has no mobility, its hyphae can grow quite long.
This is the primary mode used by the mold to spread more quickly to neighboring organisms. When you see a strawberry in a container that has been engulfed by mold, you can observe the hyphae reaching to the adjoining fruits.
Types of Mold
There are many different varieties of mold.
One of the more common types is Rhizopus stolonifer, also known as black bread mold. And don’t let the name fool you — it also enjoys other foods such as fruits and vegetables.Another well-known type of mold is Penicillium, from which the antibiotic Penicillin is derived. Penicillium can be found in a variety of places, including water-damaged structures as well as various foods.Aspergillus is a mold which is known to have several carcinogenic varieties, and when found indoors, can cause severe respiratory problems.
Causes of Mold
Mold growth is successful under certain conditions. The four factors that are necessary for mold to thrive are moisture, food, correct temperature and spores.Let’s look at a scenario in which mold grows very well: the fruit bowl on a kitchen counter. In an orange, for example, there is significant moisture. There is food within the orange itself.
The temperature in the fruit bowl is about room temperature, which is ideal. And the spores? This is the interesting part. Mold use spores to reproduce, and vast amounts are released into the air. We cannot see them, and therefore we are typically unaware that they are even there. However, when they land on that orange in the fruit bowl that has all the right conditions, the mold will happily germinate and spread.Mold can also occur in a structure that has water damage, such as the basement of a house that has flooded.
There is significant moisture in a situation like this, and indoor temperatures are just right. If the spores are released in that area, they can certainly land on walls and flooring. Drywall and studs are plant-based materials that mold can gain nutrition from, so all conditions are right.
And it is important to note that mold is certainly not limited to the indoors. There are many different types of mold that can grow in soil and on decaying organic matter. If you walk through the forest in a damp climate, you are likely to see mold growing.
Benefits of Mold
As mentioned earlier, mold is an important member of an ecosystem.
Fungi are the decomposers of our world. Dead organisms are broken down by fungi, and as a result, organic compounds are released back into the earth. Imagine the piles of dead plants and animals that would clutter the earth if they did not decay and decompose!The cycling of elements such as carbon from these organic compounds, is vital to the health of an ecosystem. When these life-giving elements are released back into the earth, they can become part of new organisms, thus continuing the cycle of life.There are other ways that mold is beneficial as well.
Many types of cheeses are made with the aid of various molds. A fun fact about Penicillium is that it is not only used in creating antibiotics, but is also used to make roquefort and camembert cheeses, as well as salami starters.
Mold is a common type of fungus that thrives under the right conditions, both indoor and out. It is heterotrophic, meaning it gains its nutrition through absorption.
Mold is composed of small strands called hyphae, which are threadlike filaments that group together to make mycelium. Mold can be a nuisance, but also has benefits in science and nature.
Notes on Mold
|Heterotrophic, so it can’t make its own food|
|Belongs to the kingdom Fungi|
|Composed of small strands called hyphae|
|Found indoors and in nature|
|Requires four factors to thrive: moisture, food, correct temperature, and spores|
The process of learning about mold via this lesson could prepare you to subsequently:
- Outline the structure and function of mold
- Remember common types of mold
- List the four factors necessary for mold to grow
- Mention areas in which mold can be found
- Highlight some of the benefits of mold