Fungi and Animals: The strange relationship between the two

Fungi and animals seem to be two completely different life domains, but there is a There are many important connections. Fungi not only affect the survival of animals and ecosystems, but also share a common evolutionary history with animals in some aspects. This article will explore the relationship between fungi and animals in detail, including their differences, similarities, symbiosis, and parasitic relationships, and their importance to human health and ecosystems.

1. Basic differences between fungi and animals

1.1 Taxonomic differences

Although both fungi and animals are eukaryotic organisms, they belong to different kingdoms in taxonomy. Animals belong to the Animal kingdom, while fungi belong to the Eukaryotic kingdom. Fungi. There are obvious differences between the two in morphological structure, nutrition mode and lifestyle:

Fungi: mainly include Mushrooms, molds, yeasts, etc. Their cell walls contain chitin, which obtains nutrients by absorbing organic matter, and most of them are decomposers or Parasites.
Animals: including mammals, birds, fish, reptiles, etc. Animal cells do not have cell walls and are usually They obtain energy by taking in food and have more complex nervous systems and motor abilities.

1.2 Different Nutrition Methods

Fungi: Fungi degrade organic matter using external decomposition enzymes and then absorb these decomposition products. This method is called external digestion.
Animals: Animals ingest food, digest it, and then absorb nutrients. They are organisms that digest food internally.

2. Similarities between fungi and animals

Although fungi and animals differ in many ways, they also have some similarities, especially in evolution and cell structure aspects.

2.1 Common evolutionary ancestor

Studies have shown that fungi and animals have a common evolutionary ancestor and are more closely related to fungi than plants are to plants. This means that animals and fungi had a common origin in the long history of the earth. Therefore, they have similarities in certain biochemical pathways, such as:

Uses of Chitin: Chitin is found in the cell walls of fungi and is also found in the exoskeletons of insects and crustaceans.
Glycogen storage: Fungi and animals store sugars in their cells as glycogen, while plants store sugars as starch.

2.2 Symbiosis and mutualism

Many fungi and animals have symbiotic relationships, where they rely on each other and benefit from each other. For example:

Insects and fungi: Some ants and termites "cultivate" fungi and rely on them as a food source, while these insects provide the fungi with the environment they need to grow.
Fungi in the digestive tract of animals: Some ruminants (such as cattle and sheep) have fungi in their digestive tracts that help break down fiber, providing the animals with indigestible plant matter.

3. Parasitic relationship between fungi and animals

Although fungi and animals can establish a mutualistic relationship, many fungi are also parasites of animals. These fungi can cause serious diseases and even cause significant impacts in the ecosystem.

3.1 Animal diseases caused by fungi

Fungal infections can affect a variety of animals, from amphibians to mammals and even humans. For example:

Chytridiomycosis: This disease caused by the chytrid fungus has had a devastating impact on amphibians (such as frogs, toads, etc.), causing a sharp decline in amphibian populations around the world.
Fungal infections in migratory birds: Some migratory birds may contract fungal infections during migration, which may affect their health and survival.

3.2 Fungal infections in humans

Humans are also susceptible to certain fungal infections, such as:

Skin diseases: Common skin diseases caused by fungi include tinea pedis (athlete's foot), tinea cruris, and ringworm.
Systemic fungal infections: Some fungi, such as Cryptococcus and Candida albicans, may cause systemic infections in people with weakened immune systems, which may even be life-threatening.

4. Importance of fungi to animals and ecosystems

4.1 Decomposers in ecosystems

Fungi play a vital role in ecosystems, especially in the decomposition of organic matter. They are able to decompose dead plant and animal bodies and provide necessary nutrients to the soil, which is essential for the circulation and maintenance of ecosystems.

Decompose animal remains: When animals die, fungi work with bacteria to decompose their remains and release organic matter back into the environment.
Help plants grow: By decomposing animal and plant remains, fungi can provide plants with minerals such as nitrogen and phosphorus that they need for growth.

4.2 As a food source for animals

Many animals feed on fungi, and these animals also play an important role in the ecosystem. For example:

Deer, rabbits, and other herbivorous animals eat wild mushrooms.
Insects, such as beetles and some ant populations rely on specific fungi as their food source.

5. Future research directions of fungi and animals

With the development of science and technology, the research on the relationship between fungi and animals has become more and more in-depth. For example, scientists are studying how to use fungi's disease resistance to help protect endangered animal species, or exploring the potential of fungi in drug development, especially antifungal drugs for animals and humans.

Although fungi and animals belong to different biological kingdoms, the relationship between them is complex and close. Fungi play an important role in the ecology, health, and disease of animals, and also play an important role as decomposers in the ecosystem. By deeply studying the relationship between fungi and animals, we can not only better understand the operation of nature, but also provide new ideas for animal protection, human health, and drug development.

Keywords: fungi-animal relationship, fungal-animal symbiosis, fungal-animal parasitism, the role of fungi in ecosystems, fungi infecting animals

Why are fungi and animals more closely related

The closer relationship between fungi and animals is mainly based on the research of evolutionary biology, especially the findings in molecular biology and genomic research. Here are several key reasons why scientists believe that fungi and animals are more closely related:

1. Common evolutionary ancestor

Fungi and animals are closely connected on the evolutionary tree. Studies have shown that fungi and animals share a common single-cell ancestor that lived about 1 billion years ago. After fungi and animals diverged, they evolved into two different kingdoms, but they still retained some common characteristics, indicating that there is an evolutionary connection between them.

2. Similarities in cell structure and biochemical characteristics

Although fungi and animals are very different in morphology, they have some similarities in cell structure and biochemical characteristics:

Chitin: The cell wall of fungi is made of chitin, which is also the main component of the exoskeleton of animals such as insects and crustaceans. This shows that they have similarities in the material synthesis pathway.
Glycogen storage: Fungi and animals store excess sugar in their cells as glycogen, while plants store it as starch. This is an important sign of their metabolic similarities.

3. Similarities in Molecular Genetics

With the development of molecular biology technology, scientists have found that fungi and animals have higher similarities at the genetic level by analyzing gene sequences, especially in some core DNA sequences and protein synthesis mechanisms:

Similarities in Ribosomal RNA Gene Sequences: Based on the analysis of ribosomal RNA, fungi and animals are classified as Opisthokonta in the gene evolution tree, indicating that they are genetically closely related.
Mitochondrial Structure: The mitochondrial genomes of fungi and animals also show high similarities, which further supports their common evolutionary ancestors.

4. Similarities in Nutrition

Fungi and animals also have some similarities in the way they obtain energy. Both are heterotrophs, which means that they cannot produce their own nutrients through photosynthesis, but need to obtain organic matter from the outside world to obtain energy.

External Digestion and Absorption: Although animals break down food through their internal digestive systems, and fungi break down external organic matter through external secretion of enzymes, both ultimately rely on absorbing nutrients to maintain life activities.

5. Evolutionary Comparison

Compared to plants, fungi and animals are less different. Fungi and animals are both metazoans, in contrast to plants and algae, which belong to the phylum Vibrio. This evolutionary relationship shows that the evolutionary trajectories of fungi and animals began to diverge early and formed independent evolutionary paths different from plants.

6. Similarity of immune system response

Studies have also shown that the recognition and response mechanisms of animal immune systems to fungi are similar to those to animal pathogens. This suggests that the immune system of animals may have retained some ways of recognizing fungi during evolution, further indicating their evolutionary relationship.

Fungi and animals are more closely related than fungi and plants, mainly because they have a common evolutionary ancestor and show significant similarities in cell structure, genomic characteristics, metabolic pathways, etc. Molecular biological research further proves that although they are very different in morphology, fungi and animals are very closely related from an evolutionary and genetic perspective

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