Lab 3 Flashcards
what is the brain eating Amoeba
Naegleria fowleri aka the brain-eating amoeba is a free-living, thermophilic microorganism that is found in warm freshwater ecosystems. It consumes bacteria, but after infecting a human it will consume their brain cells. Swimmers can inhale N. fowleri into their nasal cavities leading to brain infection and death within a week or two of symptoms appearing. Symptoms include: nausea, vomiting, headache, fever, hallucinations, and seizure.
what are protists
Eukaryotic organisms that cannot be classified as plants, fungi, or animals.
Don’t form a natural phylogenic group.
Many are unicellular, microscopic, and found in aquatic environments. Very diverse.
how can protists be divided based on feeding groups
Animal like protists are heterotrophic and consume organic matter. Plant like protists are autotrophic and photosynthesize. Others are mixotrophic and do both. Groups do not reflect phylogeny.
what are the 6 common eukaryote subgroups
- Excavata
- Rhizaria
- Chromalveolata
- Archaeplastida
- Amoebozoa
- opisthokonta
describe Excavate
Unicellular eukaryotes named fro a ventral feeding groove that gives many organisms an excavated appearance.
Most are heterotrophic and have two or more flagella.
describe Euglena
Part of Excavate
Euglena, which has chloroplast and can engulf prey. Roughly oval-shaped, rotate flagellum to move, found in aquatic environments. No cell wall. Have a pellicle (layer of proteins and microtubule fibers) arranged in strips that form a spiral around the cell.
what are Rhizarians
Mostly unicellular, heterotrophic organisms with some form of Pseudopodia (temporary, finger-like protrusions of the cytoplasmic body that aid in movement and feeding). Many Rhizarians produce a hard exokeleton. Contains Foraminifera and Radiolarians
what are Foraminifera
part of Rhizaria
Foraminifera, aka Forams, produce hard, porous shells or tests. Extend Pseudopodia out of pores in the tests to move and feed. Most are marine and found in very diverse ocean habitats, including marine sediment and fresh water. Some are planktonic and just float
What are Radiolarians
part of Rhizaria
Radiolarians form shells and are heterotrophic and planktonic. Commonly form symbiotic relations with algae. Algae produce energy, radiolarians improve access to sunshine and provided waste including CO
describe the Chromalveolate supergroup
thought to have evolved from an ancestor which engulfed a red alga cells to obtain chloroplast. No longer thought to be monophyletic but contained diatoms, paramecia, stentor, and dinoflagellates.
what are diatoms
part of Chromalveolata
Diatoms are photosynthetic plankton that are enclosed in a silica shell called a frustule. Generate 50% of earths oxygen every year. Can occur as individuals or in colonies. When in colonies their silica cell walls allow them to form geometrically-shaped structures like starts and ribbons, usually bilaterally symmetrical. Extremely abundant in both marine and freshwater. Don’t have flagella, move by secreting a mucus like substance called mucilage, allowing them to attach to a surface or move forward.
what are paramecia
Part of Chromalveolata
Paramecia are oval shaped unicellular protists. They have cilia (short little hair like things) for movement and to move food and water into the oral groove, a subcellular structure specialized for absorbing food. Engulfed food is then encapsulated in a food vacuole, which functions in digestion. Paramecia release trichocysts, tiny pointed filaments to anchor the organisms during feeding. Excess water is expelled via a star-shaped contractile vacuole. It has a macronucleus for regulating nonreproductive cell functions and a micronucleus for regulating reproduction.
what are stentor
Part of Chromalveolata
Stentor are large, trumpet-shaped organisms that can be up to 2mm when extended. They have a ring of cilia around their “mouth” end to draw in prey and move. Found in freshwater lakes and streams. Usually grouped together in colonies fixed to substrate, but can swim freely whilst contracted into an oval shape. Some algae are ingested but retained in a symbiotic relationship.
what are Dinoflagellates
Part of Chromalveolata
Dinoflagellates are red and brown unicellular organisms. There are about 2,000 marine dinoflagellate species, and there are also some freshwater species. Second most abundant marine photosynthetic organisms after diatoms. roughly half are photosynthetic and other are heterotrophic. Many have tough shell of overlapping cellulose plates. Have two flagella, one transverse and one longitudinal, both come into contact with the cingulum, a groove between the cellulose plates. The transverse flagellum is wide, flat, and wrapped around the cell in the cingulum, beats to left to propel forward and provide spin. The longitudinal flagellum beats posteriorly to steer.
what is Archaeoplastida
a supergroup that Includes land plants, red algae, green algae, and some other protists. All posses chloroplasts and several are multicellular. Includes Spirogyra, Volvox, red seaweed, and brown seaweed.
what is Spirogyra
Spirogyra is a green alga (chlorophyte) that grows in freshwater as a filamentous organisms in tread-like colonies. Unicellular but looks multicelluler. can form thick mats
what is Volvox
Volvox is another chlorophyte that lives in freshwater, forms spherical colonies of individual cells interconnected by very fine strands of cytoplasm. the sphere of cells can rotate and swim by coordinating the beating of flagella. Reproduce asexually and sexually. Daughter colonies form in both cases and grow inside the hollow sphere of the colony. To form a new colony, the clump of cells must turn itself inside out to orient their flagella properly, called colony inversion.
What are Rhodophytes
part of Archaeplastida
Red algae (Rhodophyta) are predominantly multicellular algae found in marine environments. Lack flagella and cilia, and have photosynthetic accessory pigments called Phycobiliproteins that make them red. Allows them to grow at greater depth than green algae since blue and purple wavelengths can be absorbed by red algae, and they penetrate deeper than green light.
what are brown algae
Brown Algae, or Phaeophyta, are multicellular algae found in colder marine environments. Most contain a photosynthetic accessory pigment called fucoxanthis, makes them brown-green.
how do some algae mimic plants
Some algae, including red and brown, grow into macroscopic, plant-like structures in their marine environments. The blades and stipes of seaweed resemble the leaves and stems of terrestrial palnts. They also have a holdfast that anchors the organisms to a substrate. Brown seaweed also have a float or air bladder that allows the blades to float at the surface. Not true plants since they lack roots, stems, leaves, a vascular system, internal conducting systems for fluids and nutrients.
What are the Amoebozoans
Contains a number of amoeboid protists, have ability to change shape often due to presence of pseudopodia. includes Amoeba a unicellular organisms that uses pseudopodia for locomotion and feeding.
what are Opisthokonta
Contains organisms that are propelled by a singular posterior flagellum surrounded by a collar of microvilli, nonmobile finger-like projections that aid in food digestion.
Includes Choanoflagellates which are found as both individuals and colonies. Most closely related to animals. Choanocyte cells of sponges resemble choanoflagellates
what is Köhler illumination
Sets up the microscope for optimal contrast and resolution
Involves adjusting the light intensity, light path, and the condenser.
how do you set up Köhler illumination
- Close field iris diaphragm until a small circle can be viewed
- Centre the circle of light using the condenser centering screws
- Adjust the conderser knob until the edges are sharp
- open the field Iris diaphragm until the circle of light just disappears from FOV
