Abiotic Components. Abiotic components are non-living geological, physical and chemical factors in the environment which affect ecosystems.

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1 Abiotic Components Abiotic components are non-living geological, physical and chemical factors in the environment which affect ecosystems. Abiotic components can be categorized as condition or resources. It includes : Soil Atmospheric a. Light b. Temperature c. Wind d. Water e. Atmospheric gases Physiographic Factor

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3 Plants growth requirements Soil Air Water Plants Req. Light Heat

4 Soil / Edaphic Factor Besides these factors Soil microbes and Decaying matter is also affecting.

5 Soil Texture : The size of soil particles varies from microscopic particles called clay to larger particles called sand. Loam soil is a mixture of sand and clay particles. Sandy soils are suitable for growing plants because they are well aerated, excess water drains away quickly, they warm up quickly during the day and is easy to cultivate, whereas its unsuitable because they does not retain much water and soon dry out and contain few soil nutrients required for plant growth.

6 Clay soils are suitable for plant growth because they hold large quantities of water and are rich in mineral nutrients. But they are unsuitable as they are badly aerated, soon becomes waterlogged and it also gets cold during winter. Loam soils possess desirable properties of both sand and clay - it has a high water retaining capacity, good aeration, good nutrient content.

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12 Soil air : Soil air is found in those spaces between the soil particles that are not filled with soil water. The amount of air in a soil depends on how firmly the soil is compacted. In well-aerated soil at least 20% of its volume is made up of air. Soil temperature : Soil temperature is an important ecological factor. It has been found that the temperature of soil below a depth of about 30cm is almost constant during the day but seasonal temperature differences do occur. At low temperature there is little decay by decomposers.

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14 Soil water: Soil water can be classified into three types, namely hygroscopic, capillary and gravitational water: a. Hygroscopic water occurs as a thin film of water around each soil particle. b. Capillary water is that water held in the small spaces between the soil particles and c. Gravitational water is the water which drains downwards through the soil. Soil solution :Soil solution is the decaying remains of plants and animals, together with animal excretory products that form humus. This increases the fertility of the soil.

15 Soil ph : Acidity or alkalinity of soil (the ph of the soil) influences the biological activity in soil and the availability of certain minerals. Thus the ph of soil has a greater influence on the growth and development of plants. Some plants e.g. ferns grow best in acid soils ( soils with a ph below 7), while xerophytes (desert ) grow better in alkaline soils (soils with a ph above 7).

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19 Task 3, 1 point Should be submitted within one week Compare between sandy and clay soils in term of: Particles size Soil air Water holding capacity Water retention Tillage and cultivation Temperature and freezing Etc

20 Light Sun is the major source of light and heat on earth. The variation of this solar energy creates day and night and the great change in climate from the baking deserts to the freezing poles. The earth spins on its axis of rotation every 24 hours, so that most of the world has 24 hours cycle of day and night. Why there is difference between equator and poles???

21 t esnus e isr nus t esnus e isr nus t esnus e isr nus Length of day and night Summer Spring and Autumn Winter Day Daytime Nighttime 21 December Short Long 21 March Equal nighttime Equal Daytime 21 June Long Short 21 September Equal nighttime Equal Daytime

22 As the energy passes through the atmosphere, about 20%-40% of it is absorbed by gases, dust and water vapor in the atmosphere. The energy which reaches the poles has more atmosphere to travel compared to earth thus more energy is lost before it reaches poles. Over a year equator gets twice as much as energy as either poles (Woodward 1987)

23 Cloud sur ref24% Atm. ref.7% Sky rad. Clouds 14% Sky radiatio n atm 11% Direct solar rays26% Atm. Absorpt ion14% Reflect ion 4%

24 It is the energy that is used by green plants (which contain chlorophyll) during the process of photosynthesis. Visible light is of the greatest importance to plants because it is necessary for photosynthesis. Factors such as quality of light, intensity of light and the length of the light period (day length) play an important part in an ecosystem.

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28 Light requirements of plants differ and as a result distinct layers, or stratification, can be observed in an ecosystem. Plants which grow well in bright sunlight are called heliophytes (Greek helios, sun) and plants which grow well in shady conditions are known as sciophytes (Greek skia, shade )

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30 Temperature The opening of the flowers of various plants during the day and night is often due to temperature difference between the day and night. The seed of some plants (biennials) normally germinate in the spring or summer; this phenomenon is well observed in carrots and is الحث called vernalization Some fruit trees such as the peach require a cold period each year so that it can blossom in the spring.

31 Deciduous trees نباتات متساقطة األوراق lose their leaves in winter and enter into a state of dormancy, where the buds are covered for protection against the cold. The seeds of many plants, e.g. peach and plum, must be exposed to a cold period before they germinate; this chilling ensures that seeds don't germinate during autumn, but after winter, when the seedlings have better chances to survive.

32 In animals, a distinction is made between ectothermic "cold-blooded animals and endothermic "warm-blooded animals. In desert conditions, there is greater temperature variation between day and night and organisms have distinct periods of activity, for e.g. many cacti الصب ار flower at night and are pollinated by nocturnal ليلي insects. Seasonal movements (migration) occur in some animals; examples of such animals are migratory locusts,الجراد butterflies and various marine animals like whales and penguins.

33 Seasonal changes have also a great influence on animal life in an ecosystem; torpor سبات in winter is common in reptiles and some mammals in South Africa, but a winter sleep occurs in bears of the northern hemisphere; some animals collect fat or other resources during favourable periods (often summer and autumn) and become dormant this is called hibernation الشتوي,السبات there are also animals that are dormant during warm and dry conditions ;السبات الصيفي and this is known as aestivation examples of such animals are snails القواقع and the African lung-fish.

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36 Water Plants can be classified into 3 groups according to their water requirements: Hydrophytes: Hydrophytes are plants which grow in water e.g. water-lilies and rushes. Mesophytes: Mesophytes are plants with average water requirements e.g. roses, Xerophytes: Xerophytes are plants which grow in dry environments where they often experience a shortage of water e.g. cacti and often succulents. Aloes are xerophytes.

37 Hydrophytes' Lotus

38 Mesophytes Rose

39 Xerophytes Aloe vera

40 Water requirements of animals: Terrestrial animals are also exposed to desiccation and just a few interesting adaptations are تجفيف mentioned here: Chitinous body covering of insects, the scales of birds and the ريش of reptiles, the feathers حراشف hair of mammals prevent the water loss. The tissues of animals may be tolerant to water loss e.g. a camel can live without water for long periods because its body tissues have this adaptation.

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43 Water cycle Condensation of water vapor in the air leads to precipitation the rain. Evaporation returns water vapor to the atmosphere. يغذي Infiltration of rainwater replenishes groundwater supplies. Surface runoff of rainwater replenishes surface water supplies.

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46 Wind Winds carry water vapour which may condense and fall in the form of rain/snow. Wind plays a role in pollination and seed dispersal of some plants, as well as the dispersal تشتيت of some animals, such as insects. Wind erosion can remove and redistribute topsoil, especially where vegetation is less. Warm dry winds may cause a fire hazard. Plants grown in strong winds are usually smaller than those in less windy conditions.

47 Physiographic These factors are associated with the physical nature of the area, such as altitude, slope of land and the position of the area in relation to the sun or rain-bearing winds. Altitude االرتفاع plays a role in vegetations zones. Slopes are important when considering the temperature of the soil surface on land with a northern slope, on level and on land with south facing slopes, thorn scrub شجيرات is often found growing on these slopes.

48 Atmospheric gases The most important gases used by plants and animals are oxygen, carbon dioxide and nitrogen. Oxygen: It is used by all living organisms during respiration. Carbon Dioxide: It is used by green plants during photosynthesis. Nitrogen: It is made available to plants by certain bacteria and through the action of lightning.

49 Oxygen cycle Essential for animals during respiration, released by plants as by product of photosynthesis. Cycles much like the carbon cycle. Deforestation, ocean pollution is harmful for oxygen cycle.

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52 Carbon Cycle CO 2 is taken up by plants during photosynthesis CO 2 is released by organisms during respiration and decomposition; fires, volcanoes CO 2 is also released by vehicles and industries Carbon, present in all organic molecules, moves along the food chain as one organism eats another

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55 Nitrogen cycle 78% of the volume of troposphere Most complex cycle N2 gas can t be used so it must be fixed so that organisms can use it Steps to the cycle: N Fixation occurs in plant, by bacteria Ammonification (the conversion of organic nitrogen to ammonium (NH 4+ ) by the action of decomposers (bacteria). Nitrificationa nitro group is added to an organic compound Assimilation (The conversion of nutriments أغذية into living tissues) Denitrification

56 N 2 gas is modified by nitrogen-fixing bacteria in legumes into ammonia (NH 3 ) NITROGEN FIXATION aids in production of sugars/starches Bacteria turn wastes and detritus into ammonia AMMONIFICATION released into atmosphere. NH 3 is converted into nitrite (NO 2- ) which is then used to produce nitrate (NO 3- ) - NITRIFICATION

57 Plant roots take up the ammonia and nitrate ions and converts it into amino acids, امتصاص proteins, DNA/RNA = assimilation nitrogen, present in proteins, moves through the food chain as one organism eats another نزع النتروجين.=Denitrification

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60 Phosphorus Cycle Phosphorus is released as rocks erode and plants assimilate this Very slow process Phosphorus passes from one organism to another in the food chain Decomposers release phosphorus during decomposition Mined for production of fertilizer. Mined in Tampa, FL

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63 Thank you!