Characteristics of Different Soil Types Sand, Loamy sand, Sandy loam These are well drained and aerated and workable for most of the year. They are very light to handle and quick to warm up in spring. Unless they have a very high organic matter content they are prone to drying out too quickly, and additional watering will be needed. This extra watering will also help to wash out the plant foods and lime from the soil, so they are likely to be acid (except for some coastal soils). They are often referred to as "hungry" soils and need lots of extra feeding. With careful management however, they can be amongst the most productive soil types. Medium loam, Sandy clay loam, Silt Loam These are the "average" soil types. They achieve a good balance between the ability to be very productive and the minimum of attention. The medium loam group is probably the best in this respect. Clay, Sandy clay, Clay loam, Silty clay loam, Silty clay, Silt Although these soils are difficult to work and manage, they usually have good supplies of plant foods and lime. The main drawbacks are the high water holding capacity (which means they are late to get going in spring) and the effort required to work them. You will need to catch just the right weather conditions to avoid hard work and damage to the soil structure. The use of heavy machinery (and especially rotavators) should be avoided at
Limiting Factors & the Rate of Photosynthesis James Irwin Introduction Photosynthesis can be defined as the production of simple sugars from carbon dioxide and water causing the release of sugar and oxygen. For photosynthesis to take place a plant requires carbon dioxide, water, light, a suitable temperature, chlorophyll and availability of nutrients. The raw materials of photosynthesis are carbon dioxide and water. Carbon Dioxide is the only form in which a plant can take in carbon, however, in this case using an aquatic plant, in may obtain it from hydrogen carbonate ions in the water. The limiting factors of photosynthesis are: * Light Intensity If you put a plant in total darkness, it cannot photosynthesize at all. As the amount of light is increased, the rate of photosynthesis increases until the chloroplast is working at full capacity. At this level of light intensity, adding more light makes not difference to the rate of photosynthesis. In fact, it may reduce it, because very bright light can bleach chlorophyll and make the leaf much less efficient. This graph resembles that as the increase in light intensity (which can be measured in lux) increases, the rate of photosynthesis, until another factor such as carbon dioxide or temperature, limits it. * Concentration of Carbon Dioxide Carbon dioxide is needed to make sugars in the leaf. Carbon dioxide is present
"A comparison of soils (e.g. garden/ school / park / woodland) linked to controlling environmental factors".
Kirby Kruger I.B Higher Biology Group lab test "A comparison of soils (e.g. garden/ school / park / woodland) linked to controlling environmental factors". Planning (a) Introduction and background information Soil is an abiotic factor when considered as a natural surrounding. Different soil types affects individual species of plants and animals. A good example of how soil type affects plant life is to compare two different ecosystems with different soil compositions. The desert plains in central Australia consist of mostly sandy soil. The sand does not retain water well and is very dry and arid, but the plants have adapted so that their life cycles are completed in the 30 days that follow a good rainfall. Only some succulent plants which retain water very well manage to survive throughout the whole year. A comparison may be a peat bog; cold, waterlogged and deficient in nutrients, mosses and plants which obtain minerals through "alternative" methods (carnivorism) thrive here. Soil supports the basis of the Earth's ecosystems, and the agriculture and economy of the world. The three main types of soil include: * Sandy soils, which are light, heat up quickly and retain water poorly. Particles are relatively large with relatively big airspaces. A sample with more than 90% sand particles is just called "sand". * Clay soils and silty soils, which tend to be cold,
BIOLOGY COURSEWORK YEAR 11 BY ABHINAV SARASWAT TITLE: "AN EXPERIMENT TO INVESTIGATE HOW A FACTOR AFFECTS THE RATE OF PHOTOSYNTHESIS" PLANNING EXPERIMENTAL PROCEDURES Photosynthesis is a process in which plants make their own food. Photosynthesis uses carbon dioxide, water light and chlorophyll to produce glucose and oxygen. They do this by taking in the carbon dioxide (CO2) from the air around it. The plant also needs water (H2O) and light (either from the sun or from other sources such as a light bulb). Most of the plants food is made in the palisade cell, which is in the leaf of a plant. Leaves are perfect for photosynthesis because they are flat and thin providing a large surface area for the absorption of light and gases. Photosynthesis happens in the leaf because there are a large number of chloroplasts there, each chloroplast contains the green pigment chlorophyll that gives the leaf its green colour and also captures light energy for use in the process of photosynthesis. In photosynthesis the light absorbed by chlorophyll powers the reaction that converts water and carbon dioxide into glucose and oxygen. Both animals and plants for respiration use oxygen produced by photosynthesis. The word equation for photosynthesis is: Carbon dioxide + Water Glucose + Oxygen The balanced chemical equation for photosynthesis is: 6CO2 + 6H2O
7/07/2004 Bilawal Ajmal Khan 10A H/W/K Science Investigation Aim: to investigate the effect of carbon dioxide concentration on the rate of photosynthesis. Scientific knowledge: The Elodea (Canadian pondweed) makes bubbles of oxygen when it photosynthesises. The faster it photosynthesises the faster it makes oxygen. The plant uses dissolved carbon dioxide. This can be made by adding hydrogen carbonate solution to the water. The factors which can effect how quickly a plant can make food by photosynthesis include the following. * Carbon dioxide concentration - this can be simulated by changing the volume of hydrogen carbonate solution added to the water. At low concentrations of carbon dioxide the rate of photosynthesis is very slow. As you increase the concentration of carbon dioxide the plant can make food faster and faster. There is a limit however. There comes a time when adding more carbon dioxide does not increase the rate of photosynthesis. The plant is making food as fast as it can under the conditions. * Light intensity - this can be altered by either changing the brightness of the bulb or by moving the bulb further and further away from the plant. Plants need light energy in order to make food. The more light they have the faster they can make food.
Matthew Bradfield The Importance of Water in Living Organisms Water has importance inside cells and externally. This may be because it has interesting chemical and physical properties; it can be found naturally in all three of its states. However its molecules are bonded together by hydrogen bonds, this brings up its melting and boiling points, i.e. its boiling point would be -120¢ªC rather than 100¢ªC. Also because it contains slightly negatively charged oxygen atoms and slightly positively charged hydrogen atoms making it polar. Water has been called a universal solvent because of it polarity. This means it can easily ionise substances, many compounds, whether ionic, polar or covalent will dissolve in it, therefore more reactions take place while in solution with water. Often in organisms substances must be in solution and water is the solvent. Plants can only obtain mineral salts in solution and human digestion will only dissolve soluble foods, meaning large starch molecules must be broken down into soluble sugars. Also many organisms living in water spend most of their time underwater, yet they require oxygen to respire, and as water is such a good solvent the required oxygen gas is dissolved in the water. Water is the most abundant component in any organism, the lowest is 20% in seeds, while jellyfish are 99% (hence the transparency). It plays vital roles in
The aim of this experiment is to investigate the movement of water into and out of plant cells by osmosis. The cells chosen for study will be taken from potato tubers as they provide a ready supply of uniform material.
Aim The aim of this experiment is to investigate the movement of water into and out of plant cells by osmosis. The cells chosen for study will be taken from potato tubers as they provide a ready supply of uniform material. Background Information Any substance dissolved in water is called a solute; a solvent is a liquid that is able to dissolve another substance, (a solute), to form a solution. The water content of plants varies depending on environmental conditions. In land plants it plays a vital role in structural support and mineral transport and thus a lack of water may lead to wilting or possibly death. Water is mainly absorbed through the roots, which are covered in specially adapted root hair cells, with large surface areas and thin cell walls to aid absorption by osmosis. The evaporation of water through stomata on plant leaves causes a transpiration stream, causing the water to be drawn up through xylem vessels. Osmosis is the flow of water molecules by diffusion through a partially permeable membrane from areas of high water potential (low solute concentrations) to regions of low water potential (high solute concentrations). All plant cell membranes are partially permeable, which means they allow some substances to penetrate them but not others. Whether water enters the cell by osmosis will depend on the balance between external and internal solute and water
The Effects Of Changing Light levels on the Rate of Photosynthesis Aim: To investigate a factor that affects the rate of photosynthesis. Outline: A piece of pond weed will be cut and placed into a beaker containing water and sodium hydrogen carbonate. A lamp will be shined on to the pond weed and the amount of bubbles released from the plant will be counted. The lamp will be adjusted to different distances from the plant to try and obtain different results. Photosynthesis Equation: 6CO2 + 6H2O light energy & chlorophyll C6H12O6 + 6O2 Variables: Experimental Variable- Light intensity is to be the variable explored in this investigation. Light intensity can be changed by increasing or decreasing the distance from the light source to the plant. Fixed Variables- Carbon Dioxide- CO2 concentration can affect the rate of photosynthesis since the more CO2 in the air, the more CO2 that can diffuse into the leaf. This variable can be fixed by adding a fixed amount of sodium hydrogen carbonate to the beaker and plant. Water- Water is required in the photosynthetic reaction. When plants lack water, their stomata close to prevent further water loss. At the same time, closing the stomata cells doesn't allow CO2 to diffuse into the leaf. Water is also linked to the carbon dioxide factor. Water can be kept a constant by keeping the same amount of water in the beaker. Temperature-
How the concentration of salt-water affects the rate of osmosis. Aim: To find out how the concentration of salt-water affects the rate of osmosis in a potato. Prediction: My prediction is when the concentration of salt-water gets higher the mass of the potato will get smaller. The reason for this is because when the concentration of salt is low the concentration of water will be high. The water moves from a high concentration to a low concentration. The potato has a low concentration of water so the water passes through the semi permeable membrane and the potato gains water through osmosis, increasing the mass of the potato. If the concentration of salt is high then the concentration of water will be low. The water passes from high concentration to a lower concentration so if the concentration of water outside the potato is lower than inside the water passes out of the potato reducing the mass of the potato. Method: Variables: The variables that could affect the results are: * The time the potato is exposed to the water because the experiment may not be left long enough to show any affect. * The volume of salt-water will affect the potato because there is more water and sugar and so more water will want to move making the test unfair. * The size of the potato because if they are different sizes the potato may gain more water because it can hold more making the
Transpiration Coursework -Planning I plan on conducting an experiment to find out whether the surface area and number of leaves on an individual stem has any effect on the change of weight of the leaves. Hypothesis- I predict that the leaves will all become lighter, and the more leaves on the stem, the more weight will be lost. I predict this because the water is taken back into the leaves, and is lost through the tiny holes in the leaves called stomata. The stems with more leaves on them will lose more weight, as there are more holes for the water to be lost through, also, the leave with the largest surface area will lose the most weight for the same reason. Apparatus- Test- tubes Privet bush cuttings Beaker Balance Scales Water- 15 ml Oil Measurements- I will use a balance to measure the new weight of each test- tube. I will measure the specific amount of water being poured into each test-tube, and I will measure the surface area of an average sized leaf on each stem. I will do this by drawing round the leaf on squared paper, and then counting the squares. The weight will me weighed in grams (g), the surface area will be measured in cm squares, and the weight lost will be in grams (g). Fair Test- I will make this a fair test by; keeping the amount of water at a constant amount of 15ml, with 3 drops of oil on top so that the water does not directly