Plants as Evidence! How? Lab report for Algae.
Abstract:
Algae are photosynthetic organisms found in the kingdom Protista. Even though they are classified according to their feeding and nutritional needs they also exhibit various difference amongst themselves according to color e.g brown algae, structure, organelles and also mode of movement. In this Prac Lab water from 2 different water sources was observed and viewed under the light microscope to establish the different types of algae found in each water source. For the clear water source cyanobacteria, diatoms, euglena and spiralgyra were found present, as for the muddy water euglena, diatoms, cyanobacteria, volvox, red algae were observed. There are 3 features which distinguish algae from land plants:
Body plan: There is no specialization of the algal body into root, stem etc. The photosynthetic portion of the alga is a thallus, while the attachment portion comprises of hair-like rhizoids.
No Embryo: For most algae, sperm and eggs fuse in the open water and the zygote develops into a new plant without any protection. For plant groups, the zygote develops into an embryo within the protection of the parent plant. For this reason, all plant groups are termed Embryophytes.
Reproductive structures: The gametes are produced within a single cell. There is no jacket of sterile cells protecting the gametes.
Introduction
Algae are a diverse group of simple, nucleated, plant-like aquatic organisms that are primary producers. Primary producers are able to utilize photosynthesis to create organic molecules from sunlight, water, and carbon dioxide. They Included organisms range from unicellular genera, such as chlorella and the diatoms, to multi-cellular forms, such as the giant kelp, and brown alga. Most are aquatic and autotrophic and lack the distinct cell and tissue types, such as stomata, xylem and phloem, which are found in land plants. The most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, which are a division of green algae which includes, for example, Spirogyra. They have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. (Siver 1994)
Algae constitute a polyphyletic group. They were acquired in different ways. Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria. Diatoms and brown algae are examples of algae with secondary chloroplasts derived from an endosymbiotic red alga. Algae has different forms of reproduction, asexual cell division and sexual reproduction. They lack the various structures that characterize land plants, such as the phyllids of bryophytes, rhizoids nonvascular plants, and the roots, leaves, and other organs that are found in tracheophytes (vascular plants). Most are phototrophic. Some unicellular species of green algae, golden algae, euglenids, dinoflagellates and other algae have become heterotrophs, sometimes parasitic, relying entirely on external energy sources and have limited or no photosynthetic apparatus. Algae have photosynthetic machinery derived from cyanobacteria that produce oxygen as a by-product of photosynthesis, unlike other photosynthetic bacteria such as green sulfur bacteria.(Hamed E.M (1963)
Diatoms belong to the taxonomic phylum Bacillariophyta. The diatoms are single-celled, eukaryotic organisms, having genetic information sequestered into subcellular compartments called nuclei. This characteristic distinguishes the group from other single-celled photosynthetic aquatic organisms, the blue-green algae that do not possess nuclei. Diatoms also are distinct because they secrete complex outer cell walls. Composed of pure hydrated silica within a layer of organic, carbon containing material. They are easily identified from the characteristic shape of the cells and unique refractive pattern caused by the silica in the cell wall.
Aims and Objectives
Aim: To establish the different types of algae found in different water bodies.
Objectives:
To understand how algae differs in different water bodies.
To observe the type and kind of algae found in the two different water sources (both clear and that from the pond)
To determine whether water collected from different sources contains the same type of algae.
To take note of the distinguishing characteristics of the different types of algae.
Materials and methods
Materials
Forceps, Piece of cloth from pond and a light microscope.
Methods.
Fish out a piece of cloth material from water pond in the departmental ground.
Using a pair of forceps, pick out any algal material observed on the cloth material and place it in a vial containing distilled water.
Collect a sample of water from a point furthest away from the point where the cloth material was located within the same water pond.
In the lab, compare the algal communities from the cloth material and the water sample.
Discussion
Algae species grow differently in different water bodies. They are often used to measure water quality in a source. The type of algae found in one type of water source differs from that found in other water bodies because of different nutrient and resource availability in that particular water source. Some algae like diatoms can be used to investigate the cause of death in a body found in a water body. This is done by looking for traces of diatoms in the lungs and bone marrow of the dead person, this can indicate if the person inhaled the water or not, if not the body would have been dead by the time it was placed in the water source. (Siver 1994)
Diatoms: these were found in both specimens of the water; these unicellular organisms of the kingdom Protista are characterized by a silica shell. They exist singly, although some join to form colonies. They are usually yellowish or brownish, and are found in fresh- and saltwater, in moist soil, and on the moist surface of plants. They reproduce asexually by cell division. When diatoms die they drop to the bottom, and the shells collect in the ooze.
Chlorophyta: division of the kingdom of protista consisting of the photosynthetic organism commonly known as green algae. The various species can be unicellular, multi-cellular, coenocytic or colonial.
Euglenophyta: small phylum of the kingdom Protista, consisting of mostly unicellular algae. Some euglenoids contain chloroplasts with the photosynthetic pigments. Others are heterotrophic and can ingest or absorb their food. Reproduction occurs by longitudinal cell division. Most live in freshwater. The most characteristic genus is Euglena such as those found in both the pond and clear water. (Khattab 1975)
Cyanobacteria: phylum of prokaryotic bacteria that obtain their energy through photosynthesis. They are often referred to as blue-green algae, even though it is now known that they are not related to any of the other algal groups, which are all eukaryotes. Cyanobacteria may be single-celled or colonial. Depending upon the species and environmental conditions, colonies may form filaments, sheets or even hollow balls. Some filamentous colonies show the ability to differentiate into three different cell types. Most cyanobacteria contain chlorophyll a, together with various proteins called phycobilins, which give the cells a typical blue-green to grayish-brown color. A few genera, however, lack phycobilins and have chlorophyll b as well as a, giving them a bright green color. They able to trap the energy of sunlight and enables these organisms to carry on photosynthesis. Cyanobacteria are thus autotrophic producers. Nitrogen-fixing cyanobacteria need only nitrogen and carbon dioxide to live: they are able to fix nitrogen gas, which can be absorbed by plants as ammonia, nitrites or nitrates, can be absorbed by plants and converted to protein and nucleic acids. (Hamed E.M (1963)
Spirogyra: which was found in clear water is a free-floating genus of filamentous algae belonging to the division Chlorophyta. It is a photosynthetic alga with bright grass-green filaments with spiral-shaped chloroplasts. Spirogyra grows in running streams of cool freshwater, and secretes a coating of mucous that makes it feel slippery. This is a freshwater alga found in shallow ponds, ditches and amongst vegetation at the edges of large lakes. Under favourable conditions, Spirogyra forms dense mats that float on or just beneath the surface of the water. (Gibs 1950)
Reference
Siver FA, Lord WD, McCarthy DJ (1994) Forensic limnology: The use of fresh water community ecology to link suspects to an aquatic crime scene in southern New England. Journal of Forensic Sciences 39: 847-853.
Khattab M (1975) Diagnosis of death by drowning; a quick method for detection of diatoms in bone marrow and different organs. J Egypt Med Assoc 58: 537- 546.
Hamed E.M (1963) Micromanipulators and micromanipulations, Academic Press, New York.
Gibs R.D (1950). Botany: A phylogenetic Approuch. The blkiston publishing company Philadelphia.
