Abiotic and Biotic Components PDF

Abiotic and biotic components of the environment 01/21/2025 SRZ AND QAMMIL 1 01/21/2025 SRZ AND QAMMIL 2  The way in which plants and animals grow and carry out their different activities is a result of several abiotic factors.  These ABIOTIC factors are: light temperatu...

Abiotic and biotic components of the environment 01/21/2025 SRZ AND QAMMIL 1 01/21/2025 SRZ AND QAMMIL 2  The way in which plants and animals grow and carry out their different activities is a result of several abiotic factors.  These ABIOTIC factors are: light temperature water atmospheric gases soil (edaphic) physiographic (nature of land surface) The distribution of any species of organism is limited by the distribution of suitable environments. 01/21/2025 SRZ AND QAMMIL 3 01/21/2025 SRZ AND QAMMIL 4 The biotic, or living, factors in the tropical rainforest include hundreds of thousands of species of plants, animals, bacteria and fungi. Rainforests are noteworthy for the incredible abundance of species that live in them, and they are regarded as the most diverse terrestrial habitats on the planet. Because they are the most diverse ecosystem in the world, they have more biotic factors than any other terrestrial habitat. 01/21/2025 SRZ AND QAMMIL 5 01/21/2025 SRZ AND QAMMIL 6 01/21/2025 SRZ AND QAMMIL 7 01/21/2025 SRZ AND QAMMIL 8 01/21/2025 SRZ AND QAMMIL 9 01/21/2025 SRZ AND QAMMIL 10 01/21/2025 SRZ AND QAMMIL 11 01/21/2025 SRZ AND QAMMIL 12 01/21/2025 SRZ AND QAMMIL 13 01/21/2025 SRZ AND QAMMIL 14 01/21/2025 SRZ AND QAMMIL 15 01/21/2025 SRZ AND QAMMIL 16 Examples – Plant Communites What are the three main CLIMATIC controls of plant communities are? TEMPERATURE SOLAR RADIATION PRECIPITATION Each of these factors affects the vegetation directly or indirectly through its effect on the soil. Average intensity and distribution of these factors throughout the year are both important. In turn, the distribution of plant communities, in 01/21/2025 SRZ AND QAMMIL 17  Christen Raunkiaer a Danish botanist used growth forms that had some adaptive value as a means of quantitatively relating vegetation structure to climate. Raunkiaer used a single principle characteristic that is the height of the perennating tissue from the ground surface. Perennate : To survive from one growing season to the next, often with a period of reduced or arrested growth between seasons. Used of plants or plant parts. 01/21/2025 SRZ AND QAMMIL 18 A perennating tissue - the embryonic (meristematic) tissue that remains inactive during adverse spells (winter and dry season) and then resumes growth with the return of favourable conditions (rainy season). Meristematic tissues are cells or group of cells that have the ability to divide.  Include buds, seeds, rhizomes, tubers, bulbs etc. That means the position which you see the flower or fruit is an indication of the perennating tissue height. 01/21/2025 SRZ AND QAMMIL 19  The perennating organ makes it possible for the plants to survive during unfavourable seasons. Therefore, the location of this tissue is an essential feature of the plants adaptation to climate.  The harsher the climate the lesser the plant species are likely to have buds far above the ground surface where they will fully exposed to the cold or drying power of the atmosphere.  Species with exposed perennating organs will be more prevalent in wet and warm climates than cold or dry climates.  The extreme case is represented by annuals which survive only in the highly resistant form of dormant seeds. 01/21/2025 SRZ AND QAMMIL 20  Raunkiaer used a single principle characteristic that is the height of the perennating tissue from the ground surface. Cryptophytes – Plants with the perennating bud under the soil or water. “crypto” – hidden. 01/21/2025 SRZ AND QAMMIL 21  Cryptophyte s A helophyte - perennial marsh plant that bears its overwintering buds in the mud below the surface, flowering plants above water. A marsh is a type of wetland01/21/2025 that isSRZdominated AND QAMMIL by 22  Raunkiaer used a single principle characteristic that is the height of the perennating tissue from the ground surface. Hemicryptophytes –Perennial herbs and grasses with the perennating tissue on or just below the soil surface. “crypto” - hidden. 01/21/2025 SRZ AND QAMMIL 23 Hemicryptophyte 01/21/2025 SRZ AND QAMMIL 24  Raunkiaer used a single principle characteristic that is the height of the perennating tissue from the ground surface.  Chamaephytes – Small or dwarf shrubs, herbs, mosses or ferns with the perennating bud 0-25cm from the ground  “chamae” – low, ground. 01/21/2025 SRZ AND QAMMIL 25 Chamaephytes 01/21/2025 SRZ AND QAMMIL 26  Raunkiaer used a single principle characteristic that is the height of the perennating tissue from the ground surface. Phanerophytes –Aerial plants for example trees, shrubs and lianas with the perennating organs (buds) >25cm above the grounds. “Phanero” – visible or apparent. 01/21/2025 SRZ AND QAMMIL 27 Raunkiaer used a single principle characteristic that is the height of the perennating tissue from the ground surface. 01/21/2025 SRZ AND QAMMIL 28 How do environmental factors (i.e temperature, light, water, atmospheric gases, soil, etc.) influence plant distribution? Discuss. How does variation in the quantity or intensity of the resource affect plant growth and survival? 01/21/2025 SRZ AND QAMMIL 29  How do environmental factors influence plant distribution? Temperature  Temperature is indication of the amount of heat energy in the system. Temperature is closely related to radiation this is because a great percentage of solar radiation (>70%) absorbed by the plants is converted into heat energy.  Plants cannot regulate their own temperature effectively hence they tend to assume the temperature of the environment.  Refer to them as poikilothermic or ectothermic organisms. Poikilothermic -of or relating to an organism having a body temperature that varies with the temperature of its surroundings; cold-blooded.  That is their body temperature changes markedly with the changes in external temperature. 01/21/2025 SRZ AND QAMMIL 30 Plants in varying temperature conditions will have various adaptations. Temperature strongly influences the growth and functioning of plants by regulating rates of numerous physical and biochemical processes such transpiration, photosynthesis, respiration and other metabolic processes. Temperature affects the rate of physiological processes, reproduction, and the survival or death of plants. Soil temperature influences the rate of absorption by the roots and the rate of root growth. 01/21/2025 SRZ AND QAMMIL 31  How do environmental factors influence plant distribution? Light  Lightenergy (sunlight) is the primary source of energy in nearly all ecosystems.  Why do plants need sunlight? What are the consequences of too little or too much sunlight?  It is the energy that is used by green plants (which contain chlorophyll) during the process of photosynthesis; a process during which plants manufacture organic substances by combining inorganic substances.  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) 01/21/2025 play an important SRZ AND QAMMIL 32 (i) Quality of light (wavelength or colour):  Plantsabsorb blue and red light during photosynthesis.  In terrestrial ecosystems the quality of light does not change much.  In aquatic ecosystems, the quality of light can be a LIMITING FACTOR.  Both blue and red light are absorbed and as a result do not penetrate deeply into the water.  To compensate for this, some algae have additional pigments which are able to absorb other colours as well. 01/21/2025 SRZ AND QAMMIL 33 ww.igb.fraunhofer.de 01/21/2025 saltaquarium.about.com SRZ AND QAMMIL 34 01/21/2025 SRZ AND QAMMIL 35 01/21/2025 SRZ AND QAMMIL 36 (ii) Light intensity ("strength" of light)  The intensity of the light that reaches the earth varies according to the latitude and season of the year.  The southern hemisphere receives less than 12 hours of sunlight during the period between the 21st March and the 23rd of September, but receives more than 12 hours of sunlight during the following six months. 01/21/2025 SRZ AND QAMMIL 37 (iii) Day length (length of the light period)  Certain plants flower only during certain times of the year.  One of the reasons for this is that these plants are able to "measure" the length of the night (dark periods).  However, it was thought that it is the day length (light periods) to which plants reacted and this phenomenon was termed photoperiodism.  Photoperiodism - relative lengths of daylight and darkness that effect the physiology and behaviour of an organism. 01/21/2025 SRZ AND QAMMIL 38  Short-day Plants These plants flower only if they experience nights which are longer than a certain critical length. The chrysanthemum (Chrysanthemum sp.), the poinsettia ( Euphorbia pulcherrima) and the thorn-apple (Datura stramonium; jimson weed or datura) are examples of short day plants. 01/21/2025 SRZ AND QAMMIL 39 Long-day plants These plants flower if they experience nights which are shorter than a certain critical length. Spinach, wheat, barley, clover and radish are examples of long plants. Day-neutral plants The flowering of day-neutral plants is not influenced by night length. The tomato (Lycopersicon esculeutum) and the maize plant (Zea mays) are examples of day-neutral plants. 01/21/2025 SRZ AND QAMMIL 40  Important definitions regarding Light  Phototropism Phototropism is the directional growth of plants in response to light where the direction of the stimulus determines the direction of movement; stems demonstrate positive phototropism i.e. they came towards the light when they grow.  Phototaxis Phototaxis is the movement of the whole organism in response to a unilateral light source, where the stimulus determines the direction of movement. E.g. cyanobacteria.  Photokinesis Variation in intensity of locomotory activity of animals which is dependent on the intensity of light stimulation, and not the direction, is called photokinesis.  E.g swimming rate of frog tadpoles with intensity of light. 01/21/2025 SRZ AND QAMMIL 41  Photonasty Nastic movements are non-directional response to stimuli, and are usually associated with plants. Photonasty: The movement of parts of a plant in response to a light source, but the direction of the stimulus does not determine the direction of the movement of the plant.  Plants which grow well in bright sunlight are called heliophytes (Greek helios, sun)  Plants which grow well in shady conditions are known as sciophytes (Greek skia, shade ).01/21/2025 SRZ AND QAMMIL 42  What are the feature differences comparing left and right panels plants? http://www.traitgenetics.com/en/images/ traitgenetics_images/crops_maize.jpg http://us.123rf.com/400wm/400/400/thungsarnphoto/ thungsarnphoto1211/ http://www.cambriancavingcouncil.org.uk/cavelife/devon/ thungsarnphoto121100010/16261728-small-sunflower- images/large%20images/Hartstongue%20PC%20(1).jpg plant-in-the-farm.jpg 01/21/2025 SRZ AND QAMMIL 43  Growth forms: Various growth forms represent strategies to reach sunlight ◦ Epiphytes: the so-called air plants grow on branches high in the trees, using the limbs merely for support and extracting moisture from the air and trapping the constant leaf-fall and wind- blown dust. ◦ Bromeliads (pineapple family) are especially abundant in the neotropics; the orchid family is widely distributed in all three formations of the tropical rainforest. http://www.photo-dictionary.com/ 01/21/2025 SRZ AND QAMMIL 44 photofiles/list/  Epiphytes – Aerial plants with no roots in the soil and are supported by other trees and shrubs, thus they are mainly parasites.  “epi” – besides, attached to. 01/21/2025 SRZ AND QAMMIL 45 ◦ Lianas: woody vines grow rapidly up the tree trunks when there is a temporary gap in the canopy and flower and fruit in the tree tops. ◦ Climbers: green-stemmed plants such as philodendron that remain in the understory.  Many climbers, including the ancestors of the domesticated yams (Africa) and sweet potatoes (South America), store nutrients in roots and tubers. ◦ Stranglers: these plants begin life as epiphytes in the canopy and send their roots downward to the forest floor. The fig family is well represented among stranglers. 01/21/2025 SRZ AND QAMMIL 46  Heterotrophs: non-photosynthetic plants can live on the forest floor. ◦ Parasites derive their nutrients by tapping into the roots or stems of photosynthetic species.  Rafflesia arnoldi, a root parasite of a liana, has the world's largest flower, more than three feet in diameter. It produces an odor similar to rotting http://home-at- sarawak.blogspot.com flesh to attract pollinating insects. ◦ Saprophytes derive their nutrients from decaying organic matter. http://www.srl.caltech.edu/  Some orchids employ this strategy personnel/krubal/rainforest/ Edit560s6/www/plants/ common to fungiSRZ 01/21/2025 and AND bacteria. QAMMIL 47  Water vary from Plant and animal habitats entirely aquatic environments to very dry deserts. Water is essential for life and all organisms depend on it to survive in especially desert areas. 01/21/2025 SRZ AND QAMMIL 48  Water requirements of plants Plants can be classified into 3 groups according to their water requirements:  Hydrophytes are plants which grow in water e.g. water-lilies and rushes.  Mesophytes are plants with average water requirements e.g. roses, sweetpeas.  Xerophytes are plants which grow in dry environments where they often experience a shortage of water e.g. cacti and often succulents.  Adaptations of plants to survive without water include reversed stomatal rhythms, sunken stomata, thick cuticles, small leaves (or the absence of leaves) and the presence of water-storage tissues. 01/21/2025 SRZ AND QAMMIL 49 Water requirements of animals Terrestrial animals are also exposed to desiccation. Example of adapatations of animals at dry climate? 01/21/2025 SRZ AND QAMMIL 50 A few interesting adaptations  the body covering limits water loss e.g. the chitinous body covering of insects and arachnids, the scales of reptiles, the feathers of birds and the hair of mammals.  Some mammals have few or no sweat glands and use other cooling devices, less dependant or independent of evaporative cooling.  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.  Insects are able to absorb water in the form of water vapour directly from the atmosphere for example the dew from the coastal fog is an important source of moisture for insects of the Namib. 01/21/2025 SRZ AND QAMMIL 51  Atmospheric gases The most important gases used by plants and animals: Oxygen is used by all living organisms during respiration. Carbon dioxide is used by green plants during photosynthesis. Nitrogen is made available to plants by certain bacteria and through the action of lightning. 01/21/2025 SRZ AND QAMMIL 52  Wind  Winds or air currents arise on a world-wide scale as a result of a complex interaction between hot air expanding and rising (convection) in the mid latitudes.  This has various effects on the rotation of the earth and results in a centrifugal force which tends to lift the air at the equator.  This force is known as the Coriolis force and tends to deflect winds to their left of the southern hemisphere and to the right in the northern hemisphere.  Winds carry water vapour which may condense and fall in the form of rain, snow or hail. 01/21/2025 SRZ AND QAMMIL 53  Anti- clockwise Clockwise http://www.theozonehole.com/images/ gaspcor.gif 01/21/2025 SRZ AND QAMMIL 54 Wind plays a role in pollination and seed dispersal of some plants, as well as the dispersal of some animals, such as insects. Wind erosion can remove and redistribute topsoil, especially where vegetation has been reduced. Plants exposed to strong prevailing winds are they usually smaller than those in less windy conditions. windy area = smaller plants 01/21/2025 SRZ AND QAMMIL 55 Soil (Edaphic Factors) These soil factors include texture, soil air, soil temperature, soil water, soil solution and pH, together with soil organisms and decaying matter. 01/21/2025 SRZ AND QAMMIL 56  Organic matter Surface soil Subsoil Parent rock bedrock 01/21/2025 SRZ AND QAMMIL 57  Soil The Texture size of soil particles varies from microscopic particles called clay to larger particles called sand. 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. Sandy soils is unsuitable because they do not retain much water and soon dry out and contain few soil nutrients required for plant growth. 01/21/2025 SRZ AND QAMMIL 58 Clay soils are suitable for plant growth because they hold large quantities of water and are rich in mineral nutrients. They are unsuitable in that they are badly aerated, soon becomes waterlogged and is difficult to cultivate; it also 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 and is easily cultivated. 01/21/2025 SRZ AND QAMMIL 59  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. 01/21/2025 SRZ AND QAMMIL 60  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 decay-causing micro-organisms. 01/21/2025 SRZ AND QAMMIL 61  Soil water Soilwater can be classified into three types: ◦ Hygroscopic water occurs as a thin film of water around each soil particle. ◦ Capillary water is that water held in the small spaces between the soil particles; known as available water. ◦ Gravitational water is the water which drains downwards through the soil. 01/21/2025 SRZ AND QAMMIL 62  Soil solution Soil solution (liquid phase of soil) is the decaying remains of plants and animals, together with animal excretory products and faeces, form humus. This increasesthe fertility of the soil. 01/21/2025 SRZ AND QAMMIL 63  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. 01/21/2025 SRZ AND QAMMIL 64  Physiographic factors These factors are those 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 plays a role in vegetations zones. 01/21/2025 SRZ AND QAMMIL 65  Slopes Slopes face the rain-bearing winds are covered with forest, whilst the slopes on the leeward side are in a rain-shadow and thorn scrub is often found growing on these slopes.  Example: South Eastern, Cape Town. 01/21/2025 SRZ AND QAMMIL 66 01/21/2025 SRZ AND QAMMIL 67  BIOTIC FACTORS In ecosystems, biotic factors are all living organisms and the waste that they produce. This refers to large life-forms such as trees or mammals, small life-forms such as insects and algae, and microscopic life-forms such as bacteria. These are the most diverse and easily changeable parts of ecosystems, subject to the balance of food chains and influenced by disease, pollution and abiotic conditions. 01/21/2025 SRZ AND QAMMIL 68  Biotic Factor Definition Biotic factors are all organisms in an ecological setting. Things that are considered alive are biotic factors when studying the cycles of ecosystems and how environments function as a whole. Thisrefers to animals, plants, trees and any materials they directly produce such as waste or falling leaves. 01/21/2025 SRZ AND QAMMIL 69  Biotic Structure of an Ecosystem  Producers: all plants with chlorophyll that photosynthesize: (autotrophs)  Consumers: Feed on producers or other consumers (heterotrophs) ◦ Primary: feed on producers (herbivores) ◦ Secondary: feed on primary consumers (carnivores) ◦ Tertiary:…..  Decomposers: feed on detritus (usually a bacteria or fungus that feed on dead producers, consumers, etc.) 01/21/2025 SRZ AND QAMMIL 70 01/21/2025 SRZ AND QAMMIL 71 01/21/2025 SRZ AND QAMMIL 72 01/21/2025 SRZ AND QAMMIL 73 01/21/2025 SRZ AND QAMMIL 74 01/21/2025 SRZ AND QAMMIL 75 01/21/2025 SRZ AND QAMMIL 76 01/21/2025 SRZ AND QAMMIL 77 01/21/2025 SRZ AND QAMMIL 78  Biotic Implications  Both biotic and abiotic conditions can affect how an ecosystem thrives.  Abiotic factors such as light intensity or what kind of soil is present directly affect biotic systems, but also rarely change.  Biotic changes can occur more easily and threaten an ecosystem more completely.  A disease or unbalance of predators can change one link of the food chain, which will in turn affect all lifeforms. 01/21/2025 SRZ AND QAMMIL 79 01/21/2025 SRZ AND QAMMIL 80 01/21/2025 SRZ AND QAMMIL 81 01/21/2025 SRZ AND QAMMIL 82 01/21/2025 SRZ AND QAMMIL 83 01/21/2025 SRZ AND QAMMIL 84 01/21/2025 SRZ AND QAMMIL 85  Ecological balance  A theory stipulating that natural conditions, including numbers of various animal and plant species, remain stable on their own through variations over time.  The theory, also known as balance of nature, also holds that natural equilibrium can be changed significantly by new species entering an ecosystem, the disappearance of some species, man-made changes to the environment or natural disasters. 01/21/2025 SRZ AND QAMMIL 86 01/21/2025 SRZ AND QAMMIL 87 01/21/2025 SRZ AND QAMMIL 88