What are the main properties of fungi? What makes fungi different from plants and animals?<\/p>\n\n\n\n
According to Merlin Sheldrake’s book Entangled Life<\/em>, fungi are their own kingdom of organisms\u2014they\u2019re neither plants nor animals. Although the field of mycology (the study of fungi) is growing, Sheldrake argues that many aspects of fungal biology remain a mystery.<\/p>\n\n\n\n Below we’ll look at what we’ve learned from only the six percent of all fungi species we’ve explored, particularly its properties.<\/p>\n\n\n\n\n\n\n\n According to Sheldrake, fungi are understudied for two main reasons. <\/strong>First, fungi are hard to access because many of them live underground. Second, the study of fungi requires various types of biologists to collaborate since fungi\u2019s lives are deeply intertwined with those of other organisms\u2014but it\u2019s rare for biologists to collaborate with researchers outside their own subfield (such as microbiology).<\/p>\n\n\n\n (Shortform note: Other biologists share Sheldrake\u2019s view<\/a> that fungi are understudied due to their underground habitat and the lack of collaboration among different biologists. They also identify another reason why fungi are understudied: Many fungi species are difficult to distinguish, and the technology needed to study their DNA is costly and requires extensive expertise.)<\/p>\n\n\n\n We’ll explore Sheldrake\u2019s insights on what we know and don\u2019t yet know about fungal biology. We\u2019ve organized this information into six subsections, one for each property of life<\/a>. Biologists generally agree that these are the six properties of fungi: organization, growth, response to stimuli, reproduction, energy processing, and homeostasis. <\/p>\n\n\n\n All living things have internal organization<\/a>\u2014structures such as cells, roots, and organs that organize their matter. Sheldrake explains that the cell is the main structure in unicellular fungi, such as yeast. However, most fungi are multi<\/em>cellular organisms whose cells form larger structures.<\/strong> <\/p>\n\n\n\n (Shortform note: Some fungi are dimorphic<\/em><\/a>: They switch between being unicellular yeasts and multicellular organisms. They make this switch in response to environmental changes, suggesting that this ability to transform is an adaptation that enables their survival.)In this section, we\u2019ll explore three structures found in multicellular fungi. First, we\u2019ll describe hyphae<\/em>\u2014long chains of cells surrounded by a cell wall. Then, we\u2019ll examine two larger structures made of hyphae: mycelia<\/em> (which typically grow underground) and mushrooms<\/em> (which typically grow above ground).<\/p>\n\n\n\n All organisms grow cells and larger structures<\/a> according to genetic instructions. We\u2019ll begin this section by examining the overall process of fungal growth. Next, we\u2019ll explore two types of growth: branching and fusing. Finally, we\u2019ll describe what mysteries still remain about this topic.<\/p>\n\n\n\n According to Sheldrake, multicellular fungi grow by lengthening their hyphal tips\u2014<\/em>the ends of their mycelia. <\/strong>By contrast, most other multicellular organisms grow by building layers <\/em>of cells, like a 3-D printer. (Shortform note: Some organisms grow using an approach that resembles fungi\u2019s lengthening approach and<\/em> other organisms\u2019 layering approach. For instance, a type of bacteria found in caves forms chains of cells (similar to hyphae), then it folds these chains into a three-dimensional structure<\/a> that resembles a tangled mass of yarn.)<\/p>\n\n\n\n Furthermore, Sheldrake elaborates that fungal growth is both fast and forceful. <\/strong>Let\u2019s further explore these two ideas.<\/p>\n\n\n\n Fungal growth is fast:<\/strong> Small packets containing the materials for cell growth travel through a fungus\u2019s mycelium, arrive at a hyphal tip, and add new cells to the chain\u2014at a rate of over five hundred packets per second. <\/em><\/p>\n\n\n\n Fungal growth is forceful: <\/strong>Fungi eat by digesting organic matter in their surroundings, so they need a method for inserting themselves into this matter. They use specialized hyphae that build up a high internal pressure so they can bust through cell walls.<\/p>\n\n\n\n According to Sheldrake, when hyphae lengthen, they either <\/strong>branch<\/em><\/strong> into new territory or <\/strong>fuse<\/em><\/strong> with the fungus\u2019s existing mycelium.<\/strong> Let\u2019s further explore both types of fungal growth.<\/p>\n\n\n\n Branching: <\/strong>Sheldrake explains that mycelia branch radially from a spore (a fungi\u2019s first cell<\/a>). This radial branching allows a mycelium to expand into vast territories.<\/p>\n\n\n\n Fusing:<\/strong> Whereas branching is all about expanding a fungi\u2019s territory outward<\/em>, fusing is about creating a density of connections within<\/em> a mycelium. When one hyphal strand fuses with another, it creates a shortcut, allowing materials (such as water and nutrients) and chemical signals (which we\u2019ll explore later) to travel rapidly from one part of a fungus to another part.<\/p>\n\n\n\n According to Sheldrake, many aspects of fungal growth remain a mystery. For instance, how do fungi organize their hyphae to become mushrooms? <\/strong>This question remains unanswered because an organism\u2019s organization determines its growth, and fungal organization is unlike that of any other organism. Fungi form structures such as mushrooms using one<\/em> type of cell\u2014hyphal cells\u2014whereas non-fungi form structures using multiple<\/em> types of cells. Therefore, scientists have to develop new methods and models for understanding fungi growth.<\/p>\n\n\n\n All living things react to environmental stimuli<\/a>, such as light and the presence of other organisms. According to Sheldrake, multicellular fungi\u2019s responses to stimuli are closely connected to their growth, as outlined in these two steps:<\/p>\n\n\n\n Step 1: Expansion and investigation. <\/strong>As a mycelium radiates from its spore, its many hyphal tips sense stimuli it encounters. A single mycelium might contain between a hundred and a billion hyphal tips that can detect a range of stimuli, such as light and gravity.<\/p>\n\n\n\n Step 2: Directional growth. <\/strong>When a fungus\u2019s hyphae sense a desirable stimulus (such as a nutrient source), its mycelium continues branching and merging its hyphae to surround that source. Meanwhile, it retreats from areas with no stimuli or undesirable stimuli (such as toxins).<\/p>\n\n\n\n All life forms reproduce by replicating their DNA and passing it to the next generation<\/a>. We\u2019ll begin this section by outlining the multicellular fungi\u2019s typical process for reproduction. Afterward, we\u2019ll explore what mysteries remain about fungal reproduction.<\/p>\n\n\n\n Step 1: Attraction. <\/strong>According to Sheldrake, fungi release sex pheromones (a chemical signal) to attract mates. (Shortform note: According to other researchers, fungal sex pheromones don\u2019t only attract<\/em> mates. These sex pheromones can also induce the creation of fungal sex organs<\/a>\u2014specialized hyphae that produce gametes (the equivalent of sperm and eggs).)<\/p>\n\n\n\n Step 2: Sex. <\/strong>After attraction, two fungi start having sex when a hypha from one mycelium fuses with the hypha of another. Their genetic material meets and combines in this fused channel. (Shortform note: We usually think of sex as something that happens between genetically different individuals. For a long time, scientists thought this was the only way organisms produced offspring with new genetic material. However, researchers recently discovered<\/a> that this isn\u2019t the only way of producing new genetic material: Some fungi clone themselves, have sex with their clones, and still manage to create new genetic material for their offspring.)<\/p>\n\n\n\n Step 3: Spore dispersal. <\/strong>After sex, one of the fungi grows flesh that develops into spores\u2014cells containing the new genetic material. Then, this fungus disperses those spores. Although not all fungi use mushrooms for this step, Sheldrake focuses on describing several of the ways mushrooms spread spores:<\/p>\n\n\n\n Although mycologists have uncovered many of the ways fungi reproduce, Sheldrake claims that some fungal species\u2019 processes of reproduction remain shrouded in mystery. <\/strong>For instance, scientists have yet to observe the sex of the truffle, one of the most expensive edible mushrooms. Truffles currently only grow in the wild, so improving our understanding of truffle reproduction might make it possible to cultivate these sought-after mushrooms.<\/p>\n\n\n\n All organisms acquire energy<\/a> to fuel their growth, reproduction, and other processes. Sheldrake explains that fungi, like humans and other animals, are heterotrophs: <\/em><\/strong>Instead of producing their own food (as plants do), they acquire energy by eating other organisms. However, unlike<\/em> humans and other animals, fungi digest food outside<\/em> their bodies by absorbing nutrients through their mycelia.<\/p>\n\n\n\n Throughout his book, Sheldrake highlights the variety of strategies fungi employ to access or ensnare food. In this section, we\u2019ll explore two of these strategies: predation and symbiosis. Afterward, we\u2019ll explore what mysteries still remain.<\/p>\n\n\n\n The last property of fungi is that they have strategies for maintaining homeostasis<\/em><\/a>\u2014a stable internal state\u2014amidst changing environmental conditions (such as drops in temperature). Otherwise, organisms wouldn\u2019t be able to maintain their structures, grow, respond to stimuli, reproduce, and process energy. <\/p>\n\n\n\nFungal Biology<\/strong><\/h2>\n\n\n\n
Property 1: Organization<\/strong><\/h3>\n\n\n\n
Property 2: Growth <\/strong><\/h3>\n\n\n\n
The Process of Fungal Growth<\/h4>\n\n\n\n
Two Types of Fungal Growth: Branching and Merging<\/h4>\n\n\n\n
What We Still Don\u2019t Know<\/h4>\n\n\n\n
Property 3: Response to Stimuli<\/strong><\/h3>\n\n\n\n
Property 4: Reproduction<\/strong><\/h3>\n\n\n\n
The Steps of Fungal Reproduction<\/h4>\n\n\n\n
What We Still Don\u2019t Know<\/h4>\n\n\n\n
Property 5: Energy Processing<\/strong><\/h3>\n\n\n\n
Property 6: Homeostasis<\/strong><\/h3>\n\n\n\n