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Biology Book

It's not much but these notes may help lol They're basic notes from class
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  Plants and Animals05/02/09 DEFINITIONS All the external conditions, both abiotic and biotic, affecting organisms. Environment Where an organism lives, which generally has a particular environment. Habitat A biological community and the physical environment associated with it. Ecosystem  The role of a species in its habitat or everything that it does, including itsrequirements (its total use of biotic and abiotic resources). Niche  The non-living (physical and climatic) aspects of an environment. Abiotic factor Aspects of an environment due to the presence of living organisms. Biotic factor Range of values for an environmental factor within which a species thrives andreproduces. Optimum range  The ability of an organism to withstand extreme variations in environmentalconditions. Tolerance Any change in the structure or functioning of an organism that makes it bettersuited to its environment. Adaptation  The group of plant, animal and micro-organism species inhabiting a given area. CommunityENVIRONMENT  The environment includes all the factors, both living (biotic) and non-living(abiotic), that affect the lives of organisms. BIOTIC FACTORS  These include all the relationships between members of the same species(intraspecific) and with members of other species (interspecific). ABIOTIC FACTORS  These are the physical factors in the environment that can act as stimuli for aresponse from an organism. EXAMPLES OF BIOTIC AND ABIOTIC FACTORS BIOTIC:ABIOTIC:CompetitionLightAggressionGravityCo-operationTemperaturePredator/PreyWaterReproductionChemicalsCourtshipTouchAvailability of matesSoundSuccessionPressureStratificationWindHierarchiesSubstanceParental careCurrent1  Plants and Animals09/02/09 MATCHING PREFIXES PHOTO: LightCHEMO: ChemicalHYDRO: WaterGEO: Gravity THIGMO: Touch THERMO: TemperatureRHEO: Current PLANT RESPONSES  TROPISMS- This is a growth response towards or away from an environmentalstimulus (e.g. light, water etc.) coming from one direction .If the growth is towards the stimulus we say it is positive If the growth is away from the stimulus we say it is negativeExamples of Tropisms: - If the shoot of a plant grows toward the light it is positively phototropic. - If the root of a seedling grows down it is positively geotropic. - If the roots in soil grow away from copper pipes they are negativelychemotropic. - If the branches of a vine twist around a trellis it is positively thigmotropic. - When a pollen tube grows towards a chemical in the egg it is positivelychemotropic.10/02/09 HYDROTROPISM OF SEEDLING ROOTS. AIM: To investigate the influence of moisture on direction of root growth.HYPOTHESIS: I think that the roots will grow towards the water. GEOTROPISM OF BEAN ROOTS. AIM: To investigate whether gravity alone causes roots to grow downwards.HYPOTHESIS: That they will grow downwards no matter what direction the dish isturned. NASTIC RESPONSES 2  Plants and Animals This is the movement of  plant organs in response to external stimuli. Themovements are independent of the direction of the stimuli. Examples of suchstimuli include temperature, light and humidity. Nastic movements are classifiedaccording to the nature of the stimulus. For example: PHOTONASTY:  The response to alterations in the light intensity (opening of primroseflowers in the evening). THERMONASTY:  The response to changes in temperature (opening of crocus and tulipflowers when the temperature increases). HAPTONASTY:  The response to being touched (the folding up and drooping of Mimosaleaves when touched).Nastic movements can be distinguished from tropisms as they are usually more rapid , often reversible , and their direction is independent of the stimulusdirection.Nastic responses are spontaneous and much faster when compared to tropisms.12/02/09 PLANT HORMONES, NUTRITION AND TRANSPORT - A hormone is any chemical produced in one part of the body thathas a target elsewhere in the body. - Plants have five classes of hormones. - Animals, especially chordates, have a much larger number. - Hormones and enzymes serve as control chemicals in multicellularorganisms . - One important aspect of this is the obtaining of food and/or nutrients. AUXINS: - Auxins promote stem elongation , inhibit growth of lateral buds( maintains apical dominance ). -  They are produced in the stem, buds and root tips . E.g. Indole AceticAcid (IAA) - Auxin is a plant hormone produced in the stem tip that promotes cellelongation . - Auxin moves to the darker side of the plant, causing the cells there togrow larger than corresponding cells on the lighter side of the plant. -  This produces a curving of the plant stem tip toward the light , aplant movement known as phototropism. - Auxin also plays a role in maintaining apical dominance. - Most plants have lateral (sometimes called axillary) buds located at nodes(where leaves attach to the stem). - Buds are embryonic meristems maintained in a dormant state. Auxin maintains the dormancy. - As long as sufficient Auxin is produced by the apical meristems, the lateralbuds remain dormant. - If the apex of the shoot is removed (by a browsing animal or ascientist), the Auxin is no longer produced. -  This will cause the lateral buds to break their dormancy and begin to grow.In effect the plant becomes bushier. - When a gardener trims a hedge, they are applying apical dominance. GIBBERELLINS: 3  Plants and Animals - Gibberellins promote stem elongation . They are not produced in stemtip. - Gibberellic acid was the first of this class of hormone to be discovered. CYTOKININS: - Cytokinins promote cell division . They are produced in growing areas,such as meristems at tip of the shoot. - Zeatin is a hormone in this class, and occurs in corn (Zea). ABSCISIC ACID: - Abscisic acid promotes seed dormancy by inhibiting cell growth . - It is also involved in opening and closing of stomata as leaves wilt. ETHYLENE: - Ethylene is a gas produced by ripe fruits . Why does one bad apple spoilthe whole bunch? - Ethylene is used to ripen crops at the same time. Sprayed on a field it willcause all fruits to ripen at the same time so they can be harvested. AUXIN AND PHOTOTROPISM AAbiotic response is detected in the tip.BAgar is water-based. Auxin is water-based and can dissolve in water-based thingsbut not fat-based.CAuxin is made in the tip and moves to the shaded side.DAuxin travels down one side, that side being the side that elongates.Stimulus: Light4
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