Fungi
Domain: Eukarya
Description: Organisms of the Kingdom Fungi are mostly multicellular, non-vascular, and heterotrophic. However, fungi feed through absorption. This means they release hydrolytic enzymes into their environment to break down large compounds into smaller molecules which can be easily absorbed. Multicellular fungi body structure is unique, with a mass of filaments extending throughout the ground called the hyphae. With cell walls made of chitin, the mycelium (mass of fungal hyphae) increase absorption by increasing the surface area. Fungi can reproduce sexually or asexually, which is done through the meiotic or mitotic production of spores. Divergent Event: Fungal fossils are rare, because softer organisms are harder to fossilize. But there are undisputed fungi fossils dating back 460 million years. |
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Fungi diverged from a unicellular and flagellated organism nearly 1 billion years ago, becoming separate but still very closely related to the Kingdom Animalia. Modern fungi lack flagella but early lineages like the chytrids do show evidence of a flagella. Early fungi could have come to be when spores from aquatic plants traveled to land.
Body Plan: Fungi can be either multicellular (Common Mushroom) or unicellular (yeast). Multiceullar fungi are composed of tiny filaments called hyphae. These form a large network, referred to as the mycelium. The hyphae are tubular and have cell walls of chitin. The hyphae itself is divided into many cells, called septa. They have pores, similar to plasmodesmata, which allows the flow of ribosomes to even nuclei.
Metabolism: Fungi do not ingest like animals and they do not photosynthesize like plants. Instead, they secrete powerful enzymes to break down large compounds, which then are absorbed via the hyphae. Fungi use organic molecules available in their environment for metabolism. Fungi can be of several types. Decomposer fungi break down non-living organic material. Parasitic fungi gain organic molecules from living cells within a host. And mutualistic fungi absorb nutrients from a host, but also performs actions which are beneficial to the host.
Digestion: Fungi perform extracellular digestion. Enzymes are released by fungi to break down compounds in the environment. The simple molecules can be absorbed by the fungus. Fungal extracellular digestion is complete, since it can continuously take in nutrients through the hyphae and not worry about expelling waste through the same end.
Nervous: Fungi do not have a nervous system.
Circulatory: Fungi do not have a circulatory system. Their hyphae can be thought of as a very simple circulatory system, where nutrients travel through the cytoplasm and pores of the septa.
Respiratory: Fungi perform aerobic cellular respiration through the mitochondria by taking in oxygen and sugar while releasing carbon dioxide and ATP.
Reproduction: Fungi can reproduce sexually or asexually. Sexually, the two cytoplasms of two different mycelium merge to form a plasmogamy. The two haploid nuclei eventually unite to form a diploid zygote, called the karyogamy stage. This fusion demonstrates the alternation of generations. The diploid cell undergoes meiosis, creating haploid spores. In asexual reproduction, spores simply undergo mitosis, creating genetically identical offspring. Species which perform asexual reproduction are known as mold, while an example of sexually reproducing fungi would be the Penny Bun Mushroom.
Click on the following link to learn about the phyla in Fungi:
Body Plan: Fungi can be either multicellular (Common Mushroom) or unicellular (yeast). Multiceullar fungi are composed of tiny filaments called hyphae. These form a large network, referred to as the mycelium. The hyphae are tubular and have cell walls of chitin. The hyphae itself is divided into many cells, called septa. They have pores, similar to plasmodesmata, which allows the flow of ribosomes to even nuclei.
Metabolism: Fungi do not ingest like animals and they do not photosynthesize like plants. Instead, they secrete powerful enzymes to break down large compounds, which then are absorbed via the hyphae. Fungi use organic molecules available in their environment for metabolism. Fungi can be of several types. Decomposer fungi break down non-living organic material. Parasitic fungi gain organic molecules from living cells within a host. And mutualistic fungi absorb nutrients from a host, but also performs actions which are beneficial to the host.
Digestion: Fungi perform extracellular digestion. Enzymes are released by fungi to break down compounds in the environment. The simple molecules can be absorbed by the fungus. Fungal extracellular digestion is complete, since it can continuously take in nutrients through the hyphae and not worry about expelling waste through the same end.
Nervous: Fungi do not have a nervous system.
Circulatory: Fungi do not have a circulatory system. Their hyphae can be thought of as a very simple circulatory system, where nutrients travel through the cytoplasm and pores of the septa.
Respiratory: Fungi perform aerobic cellular respiration through the mitochondria by taking in oxygen and sugar while releasing carbon dioxide and ATP.
Reproduction: Fungi can reproduce sexually or asexually. Sexually, the two cytoplasms of two different mycelium merge to form a plasmogamy. The two haploid nuclei eventually unite to form a diploid zygote, called the karyogamy stage. This fusion demonstrates the alternation of generations. The diploid cell undergoes meiosis, creating haploid spores. In asexual reproduction, spores simply undergo mitosis, creating genetically identical offspring. Species which perform asexual reproduction are known as mold, while an example of sexually reproducing fungi would be the Penny Bun Mushroom.
Click on the following link to learn about the phyla in Fungi: