Fungi Biology, Systematics, and Evolution: Key Concepts and Taxonomy

What is the estimated number of species in the Kingdom Fungi?

Over 100,000 species, with a total estimate of 1.5 million.

What is mycology?

The study of fungi.

What is the body plan of fungi primarily composed of?

Mycelium of hyphae.

What is the world's largest organism identified in the fungi kingdom?

A root rot fungus in Oregon that covers 2,200 acres and is approximately 2,400 years old.

What type of nutrition do fungi exhibit?

Heterotrophic absorptive nutrition.

What are fungi major decomposers of?

Cellulose and lignin.

What are some examples of fungal parasites?

Corn smut, wheat rust, athlete's foot, and ringworm.

What structural component distinguishes fungal cell walls?

Chitin, an aminopolysaccharide structurally similar to cellulose.

How do fungi differ from plants?

Fungi are not autotrophic, have chitin in their cell walls, and store glycogen instead of starch.

What are the six major groups of fungi currently recognized?

Zygomycetes, Ascomycota, Basidiomycota, molds, mildews, and yeasts.

What type of mutualism is formed between fungi and algae?

Lichens, which consist of a fungus and algae.

What are the three types of lichen structures?

Crustose (flat crust), foliose (leaf-like), and fruticose (shrub-like).

What do algae provide to fungi in a lichen mutualism?

Carbon source, habitat, and protection.

What do fungi provide to algae in a lichen mutualism?

Minerals, absorption from rain and dust, and protection from excessive sunlight.

What is the role of mycorrhizas in plant-fungi mutualism?

Mycorrhizas enhance nutrient absorption for plants and provide carbohydrates for fungi.

What are the two main types of mycorrhizas?

Ectomycorrhizas and endomycorrhizas.

What is the significance of Agaricus bisporus?

It is the common or button mushroom, important in culinary uses.

What is the role of Saccharomyces cerevisiae?

It is used as baker's and brewer's yeast, important for fermentation.

What are some commercial products derived from fungi?

Antibiotics like penicillin, statins like mevacor, and psychoactive drugs like psilocybin.

What are mycotoxins?

Toxic compounds produced by fungi, such as aflatoxins and those causing ergotism.

What is the ecological role of lichens?

They are pioneer species in ecological succession and can tolerate extreme conditions.

What is the impact of air pollution on lichens?

Lichens are extremely susceptible to air pollution and can serve as indicators of environmental health.

What is the significance of chitin in fungi?

Chitin provides structural support in fungal cell walls, differentiating them from plants.

What is the relationship between fungi and cellulose/lignin?

Fungi are major decomposers of cellulose and lignin, breaking down complex organic materials.

What are the ecological roles of mycorrhizas?

They increase surface area for nutrient absorption and enhance plant growth.

What is the importance of genetic and molecular characteristics in fungal taxonomy?

They are now used to classify fungi, recognizing the diversity and relationships among groups.

What is the goal of systematics?

To create a complete 'tree of life' that reflects the phylogenetic taxonomy of biodiversity.

Who is known as the Father of Taxonomy?

Carl Linnaeus, who introduced the binomial system of nomenclature and a rank-based taxonomic system.

What significant work did Linnaeus publish in 1753?

Species Plantarum, which was the first real flora and introduced the binomial naming system.

What are the main ranks in Linnaeus's taxonomic system?

Kingdom, Phylum (Division until 1993), Class, Order, Family, Genus, and Species.

What is the significance of Darwin's 'On the Origin of Species' published in 1859?

It marked the birth of systematics and emphasized the importance of common ancestry in classification.

What is the difference between natural taxonomy and artificial taxonomy?

Natural taxonomy reflects common ancestry and uses homologous characteristics, while artificial taxonomy is based on superficial similarities.

What is a clade?

A clade is a group that includes a common ancestor and all its descendants.

What is a cladogram?

A diagram that displays the relationships among clades based on common ancestry.

What is synapomorphy?

A derived trait shared by a clade that indicates common ancestry.

What is the PhyloCode?

The International Code of Phylogenetic Nomenclature that governs the naming of clades.

What is barcoding in plant taxonomy?

A method for rapid identification of plant species using unique plastid DNA sequences.

What does molecular systematics involve?

The use of nucleotide and amino acid sequences to analyze evolutionary relationships.

What is the significance of the term 'monophyletic' in taxonomy?

A monophyletic group includes an ancestor and all its descendants, which is essential for valid clades.

What is the role of classical taxonomy?

It reflects the opinions of professional taxonomists and is still used alongside cladistics.

What is the difference between paraphyletic and polyphyletic groups?

Paraphyletic groups exclude some descendants of a common ancestor, while polyphyletic groups include organisms from different ancestors.

What is the importance of the term 'Eudicots' in plant taxonomy?

Eudicots must all descend from one common ancestor, making them a valid monophyletic group.

What is a third name in scientific nomenclature?

A third name indicates subspecies, race, or geographical variants, such as Pinus elliottii densa.

What does the term 'haploid' refer to in life cycles?

The haploid stage (1N) is when an organism has one set of chromosomes, typical in gametes.

What is the diploid stage in the life cycle of sexually reproducing organisms?

The diploid stage (2N) is when an organism has two sets of chromosomes, occurring after fertilization.

What is 'alternation of generations' in plants?

A life cycle pattern where plants alternate between haploid and diploid stages.

What does the term 'species' refer to in taxonomy?

A species is the most specific rank in taxonomy, defined by a unique scientific name consisting of a genus and specific epithet.

What is the significance of the term 'homologous characteristics'?

Homologous characteristics are traits inherited from a common ancestor, used to determine evolutionary relationships.

What is meant by 'phylogenetically important characteristics'?

Characteristics that are crucial for understanding the evolutionary relationships among organisms.

What is a 'node' in a cladogram?

A node is a branch point that represents a common ancestral population in a cladogram.

What is the importance of the term 'sister groups'?

Sister groups are taxa that share a common ancestor and are used to understand evolutionary relationships.

What are algae?

Photosynthetic eukaryotes that are simple and lack vascular tissue, adapted for aquatic life.

To which kingdom are protists, including algae, often assigned?

Polyphyletic Kingdom Protista.

What is the classification status of algae?

Classification is unsettled, with monophyletic groups to be named and cladistics placement of algae.

What are the key characteristics used for classifying algae?

Number of chloroplast membranes, photosynthetic pigments (Chlorophyll a in all species), cell wall structure, and genetic, cellular, and biochemical details.

What types of reproduction do algae exhibit?

Asexual reproduction with flagellated zoospores and sexual reproduction with alternation of generations, which can be isomorphic or heteromorphic.

What is the difference between isomorphic and heteromorphic alternation of generations?

Isomorphic alternation has generations that are morphologically similar, while heteromorphic alternation has generations that are morphologically different.

What is phytoplankton and its ecological significance?

Unicellular algae that are important global producers, often experiencing population explosions or 'blooms' which can be toxic or cause dead zones due to eutrophication.

Name three examples of unicellular algae.

Coccolithophores, diatoms, and dinoflagellates.

What are the characteristics of diatoms?

They have a silicious (SiO2) cell wall, contain fucoxanthin and chlorophyll c, and can be motile by secretion.

What ecological role do diatoms play?

They are very abundant phytoplankton found at the surface of the world's oceans.

What are the defining features of dinoflagellates?

They are biflagellates, can be naked (no cell wall) or armored (with cellulose plates), and contain peridinin and chlorophyll c.

What are four special features of dinoflagellates?

1) Red tide, 2) Shellfish poisoning, 3) Bioluminescence, 4) Zooxanthellae.

What are the main structural components of multicellular algae?

Blade, stipe, and holdfast.

What are the characteristics of brown algae?

Marine seaweeds that contain fucoxanthin and chlorophyll c, commonly found in cold and temperate waters.

What is the ecological significance of brown algae?

They form kelp forests and are common in cold and temperate sea waters.

What are the characteristics of red algae?

Marine seaweeds that contain phycobilins (phycoerythrin and phycocyanin) and chlorophyll d, often found in tropical and warm waters.

What is the ecological role of red algae?

They are common in tropical and warm sea waters and can grow at great depths.

What are the characteristics of green algae?

They have diverse body plans including unicellular, colonial, coenocytic, filamentous, and flat sheets of cells, and contain chlorophyll b and beta carotene.

What is the ecological significance of green algae?

They are common in freshwater and shallow tropical sea waters.

What are some commercial uses of algae?

Food products (nori, wakame, kombu), alginates (thickeners and stabilizers), agars (growth medium), and carrageenans (emulsifiers).