Student Name___________________________ Biology STAAR Review Practice Week of 3/16-2020-3/20/2020 Unit 11: Ecosystems Reporting Category 5: Interdependence Within Environmental Systems Day Objective/TEKS Agenda TEKS B.11A (S): summarize the 1. Watch the video: Learn Biology: Good role of microorganisms in both Bacteria vs. Bad Bacteria maintaining and disrupting the https://youtu.be/IekdfJ-7Zyk health of both organisms and ecosystems 1 2. Reading, Microorganisms. While you read complete the linking literacy, Define and Examples. 3. STAAR Tune-Up: B.11A Microorganisms 4. Microorganisms: Post Assessment Microorganisms Healthy human beings have a wide array of bacteria that live within and on them. In fact, a healthy person has ten times more bacterial cells than human cells! Bacteria are as much a part of our lives as our own cells. This raises some very interesting questions about the relationship between humans and bacteria. How are bacteria helpful to humans? Are they helpful to other organisms? In what ways are microorganisms harmful to us and other organisms? Microorganisms are a diverse group The term microorganism is a broad term that encompasses all small organisms; the root “micro” means “small.” This makes for a diverse group that includes All organisms are grouped into archaea, bacteria, fungi, and some protists. one of three domains: Bacteria, Microorganisms technically do not include viruses Archaea, or Eukarya (also called because viruses are not considered living things. Eukaryota). Microorganisms span all three domains of life; domains are the largest taxonomic group of organisms. • Archaea are cells with very unusual chemistry and life strategies. Some archaea are referred to as extremophiles because they grow in very hot, very acidic, or other extreme environments. Archaea belong in their own domain (called Domain Archaea). • Bacteria are also classified into their own domain (called Domain Bacteria). This domain includes prokaryotic cells such as Escherichia coli (E. coli), which is a bacterium commonly found in the digestive tracts of animals. Although most E. coli are not harmful, a few specialized ones do cause food poisoning. • Fungi are in Domain Eukarya because they, like animals and plants, are eukaryotic. Fungi include mushrooms, yeasts, and some molds. • Protists are also in Domain Eukarya. Some protists, like kelp, are too large to be considered microorganisms. However, many protists such as phytoplankton are microorganisms. prokaryotic: lacks a eukaryotic: contains nucleus and a nucleus and membrane-bound membrane- bound organelles organelles 1 Microorganisms Beneficial Microorganisms fermentation: the anaerobic Microorganisms are used to produce a variety of food and other process involving the products. For example, yeasts are used to produce bread, wine, breakdown of glucose, and beer. Yeasts are able to live with and without oxygen because resulting they can ferment if oxygen is not present during respiration. When in the production of alcohol using yeast for food production, it is important to regulate the or lactic acid and carbon amount of oxygen present, because the yeast cells will produce dioxide different end products when respiring or fermenting. Different bacterial species make different end products when fermenting. For example, Lactobacillus is used to produce cheese, yogurt, and symbiotic relationship: a soy sauce. Other bacteria, like Acetobacter, are used to produce relationship in which two vinegar. Some bacteria are even used to produce nail polish species are interdependent; remover (acetone) and rubbing alcohol. the relationship may be beneficial to one or both In addition to being used to produce consumer goods, species, or it may be microorganisms have important symbiotic relationships with neutral or harmful to one of humans and other animals. An animal’s body is a diverse place in the species and beneficial to which microorganisms can live. In fact, microorganisms are found the other species in almost every place in and on the human body including the oral cavity, respiratory tract, intestinal tract, urogenital tract, and skin. Many of these relationships are essential to the survival of the animal. For example, microorganisms help with the following processes: •Digestion: Microorganisms in the digestive tract of animals help animals break down foods and absorb nutrients. Cows, goats, sheep, and other grazers are able to digest the cellulose found in grass and leaves because of the microorganisms found in their digestive systems. Microorganisms found in other animals, including humans, help break down a wide variety of food products. •Vitamin production: Microorganisms that live in the human body help us produce vitamins like B12 and a variety of other essential nutrients. • Immunity: Beneficial microorganisms in the human body help protect us from pathogenic (disease-causing) microorganisms by producing chemicals that kill these pathogens and by leaving no room for the pathogens to take hold. This is one of the dangers of using antibacterial soaps and gels: If the soaps or gels remove the native, beneficial microorganisms, an individual is more open to colonization by pathogenic microorganisms. Antibiotics taken to cure an infection also kill native microorganisms and result in yeast infections. Replenishing native microorganisms through probiotics can help reestablish proper balance. Probiotics are microorganisms found in food products such as yogurt. 2 Microorganisms Microorganisms also have symbiotic relationships with plants. Some plants have fungi that work with older, more developed roots to help increase the absorption of water and nutrients. These fungi are called mycorrhizae; the root “myco-“ means fungus and the root “-rrhizae” refers to the plant roots. Some legumes (bean and pea plants) have a symbiotic relationship with Rhizobia, a type of soil bacteria. In response to the presence of these bacteria, a legume plant produces root nodules that house and protect the bacteria. The bacteria, in turn, convert inorganic nitrogen from the atmosphere into usable nitrogen for the plant. This process is called nitrogen fixation. Nitrogen-fixing bacteria are also found free-living in the soil. These bacteria are essential for converting nitrogen into a usable form for all soil-dwelling plants and for other organisms. Animals obtain nitrogen compounds from the foods they eat. Plant-eaters get these compounds by consuming plants, and meat-eaters get nitrogen compounds from the plant-eaters they consume. In this way, the nitrogen-fixing bacteria are essential for life on Earth because they are the primary source of usable nitrogen for most living things. Bacteria and other microorganisms are essential for recycling nitrogen and other essential elements of life. These microorganisms decompose organisms and recycle nutrients, making them available for use by other organisms in an ecosystem. Microorganisms are also the primary food source at the bottom of certain food chains. Phytoplankton like algae, for example, is a source of food for shrimp, snails, and some small fish. Suppose an animal is born and raised in a sterile laboratory environment free of microorganisms. Another animal is raised in a standard environment containing a vast array of microorganisms. Which animal do you think would be healthier if it was released into the wild? Why? 3 Microorganisms Looking to the Future: Bioremediation Microorganisms have an astonishing array of metabolic options. Almost every chemical on Earth is able to be used and recycled by at least one microorganism. In addition to decomposing and recycling living matter, microorganisms can digest a variety of pollutants and toxins from their environment. Scientists are studying how best to use these microorganisms to help clean up environmental pollution. The methodical, artificial process of Microorganisms sometimes using live organisms to clean up the environment is called help clean up oil spills, bioremediation. including the 2010 Deep Horizon oil spill in the Gulf of One example of a microorganism that is currently being Mexico. studied is Geobacter. This tiny microbe is able to digest and remove petroleum and radioactive metals from groundwater. Geobacter has the added advantage of potentially converting these wastes to biofuels. Scientists are hopeful about future environmental applications of this exciting microorganism. Harmful Microorganisms Some microorganisms feed themselves in a way that causes harm to other organisms. These microorganisms are called pathogens. Pathogens cause a number of different diseases in humans including meningitis, pneumonia, urinary tract infections, and whooping cough. For example, whooping cough (or pertussis) is caused by a bacterium called Bordetella pertussis. This bacterium produces a toxin, attacks the lungs, and causes an increased secretion of mucus by its human host. These activities of the bacterium cause coughing. The most easily recognized symptom of whooping cough is a cough followed by a rapid inhale of air (whoop). Animals have evolved a variety of ways to avoid pathogens and stay healthy. Our immune system has three main strategies for fighting pathogens. •Barriers: Our skin includes a thick layer of cells that protects us from foreign matter and cells. Openings in our bodies, like our nostrils, are protected by mucus that traps and removes debris. •Nonspecific immune response: Specialized cells in the body recognize and remove any foreign matter or cell. •Specific immune response: White blood