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37 Cards in this Set
- Front
- Back
Habitat
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The place in which an organism lives
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Biota
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Life forms
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Biosphere
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'layer' of the Earth, including waters, lower atmosphere and soil, which supports life; the sum total of all the Earth's ecosystems
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Biomes
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Areas od the Earth linked by a common feature
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Optimum range
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Narrow range within the tolerance range an organism has for an aboitic factor, and at which the organism functions best at
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Physiological stress
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Stess caused when an organism experiences conditions outside its tolerance range
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Abiotic
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Non-living, environmental factors that can affect the organisms chance of survival
Eg. temperature, light intensity etc |
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Biotic
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Living, environmental factors that can affect the organisms chance of survival
Eg. more of the organisms kind, predators, humans etc |
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Tolerance Range
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This includes the optimum rnage ad the zone of physiological stress. It is where a species can survive.
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Zone of Intolerance
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This is the area outside the tolerance range where species cannot survive
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Ecosystem
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Ecosystem= Habitat + community of living things
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Qualitative
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descriptions that do not involve measurements
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Quanitiative
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measurements that can be quantified - expressed in units
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Stratification
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vertical differences in abiotic conditions that give rise to distinctive zones
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Zonation
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horizontal differences in abiotic conditions that give rise to distinctive zones
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Phytohormones
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plant growth substances
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Coleoptiles
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the sheath-like covering of the young growing tips of grasses.
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Gibberellins
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Promote cell division and elongation in plant shoots; extend internodes and can raise flower heads (bolting).
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Cytokinins
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Stimulate cell division and the middle layer of cells (mesophyll) in leaves. They tend to be concerntarted in the startchy material in seeds (endosperm) and in young fruit.
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Abscisic acid
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Generally acts as an inhibitor. It promotes closure of stomata particularily during times of water stress; stimulates dormancy in seeds and buds.
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Ethylene
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In gaseous state, it is significant in ripening fruits by stimulating the conversion of starch to sugars, increasing the sweetnes of the fruit. Ethylene also stimulates colour change and softening tissues of ripening fruit as in tomatoes and bananas
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Photoperiodism
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refers to the physiological reaction of organisms to the length of day or night
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Phytochrome
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a pigment that plants use to detect light (a plant photoreceptor) in the red region of the spectrum
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Short-day
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describes plants that flower after a long period of darkness (better described as long-night plants).
Eg. potatoes |
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Long-day
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describes the plants that require long peroids of daylight before flowering.
Eg. spinach or lettuce |
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Day-neutral
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Describes plants that flower regardless of the lengths of daylight or darkness.
Eg. tomatoes and cucumbers |
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Vernalisation
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Some species cannot flower unless expossed to a period of very cold weather before spring growth. They need a "cold snap"
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Dormancy
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Some plants shut down some of their activities during unfavouable conditions. Energy level requirments are lowered to a minimum when temperatures are low or water scarce.
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Taxis
(Responses in plants) |
movement of a whole organism in response, such as a unicellular alga towards a light source (positive phototaxis) or away from a high concerntration of a particular chemicl in a solution (negative phototaxis)
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Tropism
(Responses in plants) |
growth movement in response to an external stimulus in which the direction of the stimulus determines the direction of the response (referred to as a unilateral or unidirectional stimulus)
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Nastic
(Responses in plants) |
movement of a plant organ that is not determined by the direction of the stimulus (non-directional), such as the opening and closing of flowers in 'sleep' movements
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Phototropism
(Tropism) |
Stimulus: Light
Response- Positive: shoots grow towards the light Negative: roots (if responsive) grown away |
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Geotropism
(Tropism) |
Stimulus: Gravity
Repsonse- Positive: roots grown downwards Negative: shoots grow upwards |
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Hydrotropism
(Tropism) |
Stimulus: Water
Response: Roots grow towards water |
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Thigmotropism
(Tropism) |
Stimulus: Touch, contact
Response: Stems and tendrils grow around or against points of contact with solid objects such as stems of other plants. |
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Chemotropism
(Tropism) |
Stimulus: Chemicals
Response- Positive: pollen tubes of some plants are ttracted to the stigma of the same species, enabling fertilisation. The ovary releases chemicals that produce a positive response. |
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Epiphytes
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Are aerial plants. They grow on the branches and trunks of other plants, but are not parasitic.They include mosses, lichens, orchids and ferns of many kinds and bromeliads. They gain advantage in competing for light by living high up on rainforest trees. As they have no contact with the soil, their main difficulty is obtaining nutrients and in holding water that comes their way
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