Lab Report
Materials: Dissecting Microscope, Bread mold Rhizopus( in a square glass sample), Aspergillus sample, a Mushroom, a Lichen, plastic dish, cover slip, Forceps, prepared slide, distilled water, petri dish, razor blade, wet mount.
Methods: We gathered all the materials at one place, which included the microscope, prepared slides, specimens and materials for wet mounts. We observed different slides and samples from the above-mentioned mushrooms and lichens through the microscope. We took a small specimens of Rhizopus and Apergillus on glass dish, and the mushroom and lichen on a plastic dish and observed them individually under the microscope.
Results: Fungi constitute a diverse taxa that helps maintain the biogeochemical cycle by serving the role of decomposers, parasites and mutualistic symbionts to plants. A single fungal cell consists of hyphae which are tubular structures. These tube like structures are again compartmentalized by walls called septum. Penicillium Hyphae are spectate i.e. they are divided into small chambers, while that of Rhizopus is aseptate, which means there are no compartments within the hyphae. A network of hypha form the mycelium. These mycelium also release digestive enzyme that break down complex food matters outside the fungus and are reabsorbed back by rhizoids. The haustorium is a tube like appendage that is designed to penetrate host tissue and draw nutrition from it, this structure indicates that fungus are adapted for a terrestrial lifestyle. Fungus can reproduce, sexually, asexually as well as by vegetative means(Campbell, Reece, Taylor, Simon, & Dickey, 2009).
Spores: Spores can be of various types an example is the conidium or conidia that are single celled or multi-celled spores that develop inside specialized hyphae known as conidiophores. The formation of spores indicates that the propagation of fungus needs to take place via aerial route over short distances and this indicates at a terrestrial adaptation. The sporangium holds the spores for a certain period of time and later releases them outside.
Fungi can also reproduce through sexual reproduction. Three phases of sexual reproduction are plasmogamy, karyogamy and meiosis. Ascomycota creates structures for sexual reproduction in fungus called gametangia, while the male gametangia is called spermatium the female portion is called ascogonium. When the spermatium and ascognium fuse together the sexual reproduction takes place.
A lichen is not a single organism but a composite organisms that is formed by the association between an algae, cyanobacteria that live in the filaments of fungus and form a symbiotic relationship that is beneficial to all three organisms.
Fungi have rhizoids which act as tiny root hairs that absorb water by capillary action. If fungus had an aquatic origin, they could have simply absorbed water from the surroundings. The presence of rhizoid like structure showcases that fungus has developed for a terrestrial life system.
Discussion: fungi evolved for a primarily terrestrial life. Structures such as mycelia and sporangia are designed to help the fungi survive and propagate in the terrestrial environment. From the above structures we can see that although fungi are found both in land and water, certain structures like haustorium, rhizoid, gametangia etc. indicate that fungi have evolved to lead a more terrestrial lifestyle and they share quite a few structures with plants. For example the rhizoids and haustorium are serve the function of roots in plants, the Rhizoids takes up water by capillary action and the haustorium takes up nutrients from the host. Even the method of reproduction by spores shows signs of terrestrial adaptation. Based on the above-mentioned we fail to reject the hypothesis that fungi have developed specialized structures similar to plants for the purpose of terrestrial adaptation.
Keywords: Spores, sporangia, Conidiophores, hyphae, mycelium, haustoria, gametangia, lichen.
References
Campbell, N. A., Reece, J. B., Taylor, M. R., Simon, E. J., & Dickey, J. (2009). Biology: concepts & connections (Vol. 3). Pearson/Benjamin Cummings.
Vodopich, Darrell and Moore, Randle. Biology Laboratory Manual. 8th . Edition. McGraw-Hill Companies. (EX. 27)
