Classification by Aristotle and Theophrastus Early Classification Living Things Plants Animals
Classification by Aristotle and Theophrastus Aristotle's Classification Animals Air Dwellers Land Dwellers Water Dwellers
Classification by Aristotle and Theophrastus Theophrastus's Classification Plants Herbs (soft stem) Shrubs (Several woddy stems) Trees (single woody stem)
How the 6 kingdoms came about At first, only two kingdoms were recognized Then 5 kingdoms (where protists had both plant & animal qualities) And now there are 6 kingdoms, organized into 3 domains
6 Kingdom Classification
Kingdom Classification Organisms are classified based upon 4 main criteria: How it gets food? Is it autotrophic or heterotrophic? Is it Unicellular (one cell) or multi-cellular (more than one)? Does it have a nucleus? Is it Prokaryotic or Eukaryotic? Movement Is it motile or non-motile?
Monera Eubacteria - Bacteria
Kingdom Monera Most are unicellular some colonize All are Prokaryotic Usually classified according to shape, cell wall and nutrition. cocci (round-shaped), bacilli (rod-shaped), and spirilli (spiralshaped) may be photosynthetic, chemosynthetic, or feed by absorption. Asexual reproduction through Binary fission.
Bacterial Shape
Gram Positive (purple) vs. Gram Negative (Pink) + ve have a thick peptidoglycan cell wall
Reproduction - Binary Fission 1. As bacterial cell grows, it duplicates its nucleic acid. 2. The cell elongates and the chromosome divides. 3. A cell partition or septum forms between the chromosomes. 4. The septum completes itself and distinct walls form. 5. The cell separates into two new cells. This process takes as little as 20 minutes. One cell can become 30 000 in 5 hours. Prokaryotes have a single, circular chromosome rather than the sets of chromosomes found in the more familiar eukaryotes, mitosis does not occur in prokaryotes. Instead, most replicate via a process of binary fission.
Replication
Conjugation Sexual reproduction by bacteria. Bacteria join through a pili that allows genetic information to transfer from one cell to another. Plasmids are small loops of DNA separate from the main DNA that can move from cell to cell sharing its genetic information.
Not All Bad Many people only consider bacteria to be the cause of illness and death. But there are beneficial bacteria: in your intestine, they help digest food. in cow stomachs to help them digest grass. in yogurt and cheese, it curdles the milk. Cyanobacteria are believed to be the first organisms to perform photosynthesis. They released oxygen as a waste product, and thus changed the composition of our atmosphere, and set the stage for other forms of life. Other cyanobacteria are capable of fixing nitrogen into nitrates, an essential part of the nitrogen cycle. Bacteria and algae live in symbiosis to form lichen, a major food source for caribou.
Bacterial Resistance Antibiotics stop bacteria in a number of ways. They can prevent cell wall growth, some kill the bacteria directly and others prevent it from reproducing. Over time, bacteria mutate and evolve new strains resistant to antibiotics that attack them. if an antibiotic kills 99.9% of bacteria, the 0.01% that is not affected can grow, and flourish. Antibiotic resistance is becoming a growing concern in our healthcare system.
Kingdom Archaea Very similar in appearance to eubacteria ; however, the composition of the cell walls and nucleic acids may be drastically different.
Methanogens- live free of O2 and break down inorganic compounds like H2S (hydrogen sulfide) and releases methane (CH4) as a waste product. Types
Halophiles- saltloving bacteria
Thermoacidophilesarchaea bacteria that love and flourish in acidic or extreme temperatures.
Liard Hot Springs
Do Page 139: #1, 2, 3, 4, 7, 8 and 9
Protista
Kingdom Protista Most are unicellular Eukaryotic may be photosynthetic, may feed by absorption, or may ingest food.
Classified according to nutrition There are three groupings for Protists (so far) Protozoa (animal-like protists) : heterotrophs that ingest or absorb food. Algae (plant-like protists) : autotrophs that carry out photosynthesis. Slime moulds and Water moulds (fungus-like protists) : heterotrophic Read pg 140
Protozoa (Animal-like Protists) Meaning first animals Feed on other organisms, living or dead. Complex structures and reproduction
Life Cycle See Page 146 Plasmodium vivax a Sporozoan human parasite is reposible for one type of malaria. A mosquito bites an infected person, ingesting the P. vivax cells. The gametes (reproductive cells) fuse to form a (diploid) zygote inside the gut of the mosquito. The zygote divides many times producing many spore-like structures (sporozites) that become released.
The sporozoites invade the salivary glands of the mosquito, and are injected into a new host while the mosquito feeds. Once inside the host (human) sporozoites will reproduce asexually in the liver to form another spore-like cell. These cells then leave the liver and invade red blood cells, where they reproduce many times. Red blood cells rupture, releasing toxic substances and more spores that infect neighboring RBC s.
Algae (Plant-like Protists) Simple, aquatic, chlorophyll-containing organisms. Photosynthesizes Ranging in size from single celled entities to giants 60 meters long (seaweeds).
Slime/Water Moulds (Fungus-like) These are difficult to classify. They have characteristics of fungus, plant and protozoa at the same time. These cute guys make great pets!!!
Fungi
Kingdom Fungi Most multicellular, some are unicellular (Yeasts). Eukaryotic cell structure Absorptive Heterotrophs Non Motile
Multi-cellular Structure The bodies are made up of a network of fine filaments called Hyphae. The bulk of a Fungus is under the soil as a branching network of hyphae called a mycelium. Hyphae can appear as either large loosely branching multinucleated cells or divided into individual cells with walls (Septa) Fungi do have cell walls, but they are made with chitin, a material similar to the external skeleton of insects.
Nutrition All are heterotrophs, and most are saprophytes (organisms that break down dead matter). Fungus release digestive enzymes from their mycelium and absorb the digested nutrients in through the root system. This digestion takes place outside the organsim, so it is referred to as extracellular digestion.
Reproduction Fungi have both asexual and sexual means of reproduction. Asexual methods: Fragmentation a piece of hyphae breaks of and grows a new mycelia. Spore formation many fungi produce spores to be carried by animals or wind to new locations. Spores can grow directly into a new organsim. Budding a yeast cell reproduces by budding off the original parent. See page 157
Zygomycota You have seen this mold anytime you have found a piece of stale bread. The small black dots you may have seen are their reproductive structures Like bacteria this group of fungi can perform sexual reproduction when conditions are unfavourable. They produce zygospores, which is where it gets its name.
Life cycle of Rhizopus stolonifera Rhizopus have two types of hyphae: Stolons which spread out over the surface. Rhizoids penetrate deep to anchor the mold and are used for food absorption. Hyphae can also be two mating types, either a + or strand. Two haploid (having only half the number of chromosomes) hyphae of opposite mating strands fuse to form a dilpoid (having the full number of chromosomes) zygospore.
A thick wall develops around the zygospore to protect it from damage, and it will remain dormant until conditions are favorable for growing again. When conditions are right the zygospore will absorb water and reproduce asexually into a third form of hyphae called a sporangiophore that projects upwards, carrying on it many sporangia (spore-bearing capsule). Asexual spores develop inside the sporangia and are released when the capsule splits open.