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25 Cards in this Set
- Front
- Back
Hardy-Weinberg theorem requires that the following five conditions be met
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1. The population must be very large. The effect of random changes in allele frequencies (genetic drift) is greatly reduced in a population with large numbers of individuals.
2. Mating is random. Individuals within a population show no preference for mating with individuals of a particular phenotype. 3. There are no net changes in the gene pool due to mutation; that is the number of mutations from A to a must be equal to the number of mutations a to A. 4. There is no migration of individuals into or out of the population, and therefore, no gene flow among populations. 5. There is no selective advantage to any allele. All individuals in a population have an equal chance of surviving and reproducing; all genotypes are equally viable and all alleles should be inherited equally. Consequently, no natural selection is acting on the population. |
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genetic drift
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Genetic Drift is the random change in allele frequency from one generation to the next. It can become an important evolutionary force when a population undergoes a drastic reduction in size due to chance events such as a small group breaking away to colonize a new habitat area (such as an island), depletion of food supply, loss of habitat, outbreak of disease, and/or natural disasters. This reduction in population size or genetic bottleneck results in unpredictable combinations of alleles in the generations following the bottleneck. If a population is small enough, genetic drift could lead to the loss of all but one possible allele on a particular gene locus in a population. That remaining allele would then be fixed in the population. Alleles may be eliminated from a population regardless of whether they are beneficial or not. Under these conditions genetic drift can prevent the maintenance of Hardy-Weinberg equilibrium.
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founder effect
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Founder Effect is the random difference in allele frequency that occurs when a small population splinters off from the main population.
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natural selection
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Natural Selection is a non-random process that favors adaptive traits (traits that increase survival and reproduction). If these adaptive traits have a genetic basis, natural selection can result in evolution.
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3 domains
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There are two types of prokaryotes (Fig. 1), making up two of the three domains of life: Archaea and Bacteria. The third domain, Eukarya, includes all other organisms: protists, fungi, plants, and animals, all of which are composed of eukaryotic cells.
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Diff between archaea and bacteria
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Of the prokaryotes, bacteria are much more common and ubiquitous than archaea. They are found pretty much everywhere on Earth! They can be found in the ice of Antarctica, at the bottom of the oceans, deep in the soil, as symbionts in the guts of animals (including you!), and every nonsterile surface you come into contact with in your day-to-day life. You have more bacterial cells in and on your body than you have your own cells. Archaea, on the other hand, are much less common. Although some can be found in the soil or oceans, most are extremophiles. This means that most archaea thrive in extreme environments, such as those that experience high temperatures, high salinity, or high acidity.
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Bacteria
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Pathogenic bacteria, cyanobacteria, Nitrogen-fixing bacteria
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Cyanobacteria
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Have the ability to photosynthesize like plants. They provide a large proportion of the oxygen in the atmosphere and serve as imp. primary producers in natural ecosystems.
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Nitrogen fixing bacteria
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found associated with plant roots and are able to convert atmospheric nitrogen into forms that can be used by plants. Ex. Rhizobium.
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Cell shapes
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Coccus - circle
Bacillus - rod shaped Vibrio - comma shaped Spirillum - spiral |
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Cyanobacteria - Anabaena
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Heterocysts - specialized nitrogen fixing cells
Akinetes - thick walled dormant cell derived from the enlargement of a vegetative cell. It serves as a survival structures. |
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Cyanobacteria- Nostoc
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Gelatinous sheath
Heterocytes/cysts akinetes |
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cyanobacteria
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Oscillatoria
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Gram negative
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thin peptidoglycan layer with an outer membrane. Fuchsia.
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Gram Positive
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thick peptidoglycan layer with no outer membrane.Purple
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Gram Stain Procedure
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1. Heat fix bacteria to slid
2. Crystal violet - rinse 3. Grams iodine - don't rinse 4. Decolorizer - most imp step, rinse 5. Safranin - counterstain, rinse |
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Protists
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Evolutionary Imp - Evolved from prok to euk. Earths first eukaryotes
- Not classified as animals, plants or fungi. But closely related. Categorized by ecological role, habitat or motility. Eukaryotic - membrane bound organelles Mostly unicellular |
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Supergroup Excavata
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Specialized feeding groove.
Exhibit phagocytosis. Endosymbiosis - acquired plastids via phagocytosis. Secondary endosymbiosis. - Some are heterotrophic, some are photosynthetic. |
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SuperGroup Excavata
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Euglena
Trypanosoma Giardia |
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SuperGroup Archaeplastida
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Chlamydomonas
Spirogyra Volvox Ulva |
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Supergroup Alveolata
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Dinoflagellates
Ciliates Paramecium Stentor |
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Supergroup Stramenopila
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Diatoms
Brown Algae Actinosphaerium |
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Supergroup Amoebozoa
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Amoebas
Slime mold |
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Supergroup Rhizaria
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Radiolarians
Foraminiferans |
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Phylum for organisms in Supergroup Archaeplastida
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Phylum Chlorophyta
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