* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download World of Plants Notes
Ecology of Banksia wikipedia , lookup
Gartons Agricultural Plant Breeders wikipedia , lookup
History of herbalism wikipedia , lookup
Plant stress measurement wikipedia , lookup
Plant nutrition wikipedia , lookup
History of botany wikipedia , lookup
Plant use of endophytic fungi in defense wikipedia , lookup
Photosynthesis wikipedia , lookup
Plant secondary metabolism wikipedia , lookup
Evolutionary history of plants wikipedia , lookup
Plant defense against herbivory wikipedia , lookup
Pollination wikipedia , lookup
Ornamental bulbous plant wikipedia , lookup
Plant breeding wikipedia , lookup
Plant evolutionary developmental biology wikipedia , lookup
Plant morphology wikipedia , lookup
Plant physiology wikipedia , lookup
Plant ecology wikipedia , lookup
Sustainable landscaping wikipedia , lookup
Perovskia atriplicifolia wikipedia , lookup
Flowering plant wikipedia , lookup
Introducing Plants The Sun is the source of all energy on Earth. Green plants are the link between man and the Sun. Without green plants most life on Earth would not exist. Give examples of advantages of there being a wide variety of plants There is an enormous range of plants on Earth. This variety has many advantages: There is a large range of characteristics for breeding from There is a greater choice for use as raw materials They provide different sources of food for many animals They provide a variety of habitats for many animals They maintain the gas balance of the atmosphere Green plants take in carbon dioxide and produce oxygen They make homes, gardens and all ecosystems more beautiful Describe 3 specialised uses of plants There are countless ways in which man uses plants. Here are three: Food Raw materials Medicines Explain possible consequences to man and other animals of a reduction in the variety of species If any species of plant is allowed to die out, the possible consequences are very serious both for man and the other living things that share our planet. Here are a few possible consequences: Many plants represent potential resources (food or raw materials) which may become essential in the future. Lots of plants may contain valuable products that have not yet been discovered Every plant provides food or shelter for a variety of other organisms, some of which may only be able to live on that particular species. Biologists can transfer useful genetic characteristics from one species to another. The loss of any species will reduce the gene pool (number of genes in the world). 1 Describe a production or refining process, e.g. malting barley, rape seed, raspberries, timber Timber production There are a number of steps involved in the production of timber Seeds are sown in nurseries After 2-4 years small trees are planted out in rows. After 15 years a third of the trees are removed to thin them out. This involves removing the smaller and poorer trees. Thinning continues at 5 year intervals and each thinning is more valuable than the one before. At 40-50 years the forest is finally harvested and the replanting programme is started over again. Describe two potential uses of plants or plant products e.g. new medicines, new food sources Scientists are always looking to find new uses of plants and plant products. New Sources of Food Earth is thought to have 75 000 species o edible plant. At present only about 20 species are used to produce most of the world’s food. New Sources of Medicines It is possible that, for example, in the rainforest there may be plants that could be used to cure disease. However deforestation means that some species may lost forever. Growing Plants All living things must reproduce to ensure that they do not become extinct. In order to reproduce, flowering plants produce seeds. Describe the functions of the three main parts of the seed of a dicotyledon, i.e. seed coat, embryo, food store Structure of a seed A seed is made up of an embryo - small undeveloped plant a food store - food supply until the plant can make its own a seed coat/testa - tough protective coat 2 Describe the effect of temperature and the availability of water and oxygen on germination Germination is the development of a plant embryo into an independent plant with green leaves. During germination the food store present is used to give the young plant energy for growth. Seeds need certain conditions in order to germinate. To germinate seeds need: Water, Oxygen, Warmth Describe the changes in percentage germination that occurs over a range of temperatures Almost no seed will germinate at temperatures below 5C. High temperatures (above 45C) also prevent germination. Between 5C and 45C, percentage germination increases with increases temperature until a temperature where germination is at its best. This is called its optimum temperature. Germination does not take place at high temperatures as enzymes are denatured. Describe the functions of the parts of flowers, i.e. sepal, petal, stamen, anther, stigma, ovary, nectary Structure Sepal Petal Stamen Function Protects the unopened flower bud Brightly coloured to attract insects Male part of the flower, contains anther and filament Produces male gametes (pollen) Top of the female part which collects the pollen Produces female sex cells (ovules) Produce sugary nectar which attracts insects Anther Stigma Ovary Nectary Describe the methods of pollination Pollination is the transfer of pollen from the anther to the stigma. self-pollination Pollen is transferred from the anther of one flower to the stigma of the same flower or another flower on the same plant 3 cross-pollination Pollen is transferred from the anther of one flower to the stigma of a flower on a different plant There are 2 methods of pollination: Insect Wind Insect pollination Pollen is brushed onto the insect’s body when it sucks nectar from a flower. Pollen is carried by the insect. When the insect goes to another flower the pollen grains stick to the stigma. Wind pollination Pollen is blown by the wind from the anther hanging outside of the flower. Pollen is carried by the wind. Pollen sticks to stigmas hanging outside of the flower. Explain the structure of wind- and insect-pollinated flowers in relation to sexual reproduction You can tell whether a plant is insect- or wind- pollinated by looking at the flowers it produces Insect pollinated flowers Wind pollinated flowers Large brightly coloured petals Scent Nectar Large, rough pollen grains Anthers and stigmas inside flower very small petals no scent no nectar small, smooth pollen grains anthers and stigmas outside flower 4 Describe the growth of the pollen tube and fusion of gametes When a pollen grain lands on the stigma, it grows a tube down through the style into the ovary. This allows the male nucleus to fuse with the nucleus of the female gamete. Fusion of the 2 nuclei is called fertilisation. Fertilisation produces a zygote. Describe fertilisation and fruit formation After fertilisation ovules become seeds each contains an embryo, a seed coat and a food store. The ovary becomes a fruit this is often fleshy and succulent (e.g. plums etc) but can also be very tough and dry (e.g. nuts) Describe one example of each of the following different dispersal mechanisms: wind, animal – internal, animal -external The seeds and fruits must be carried away (dispersed) from the parent plant so that there is less competition for: Light Water Nutrients There are 3 main methods of seed dispersal: Wind Animal internal Animal external The structure of the seeds and fruits is suited to its method of dispersal. Wind Fruits are light and have extensions e.g. parachutes or wings so that they will have greater air resistance and catch the wind. The poppy seeds are like pepper pots that are shaken by the wind. Animal internal Fruits are usually brightly coloured and juicy to encourage the animal to eat them. The seeds are indigestible which allows them to pass out of the animal far away from the parent. 5 Animal external The fruits have hooks that are used to attach them to the animal’s coat and be dropped off later. Describe ways of propagating flowering plants artificially by cuttings and grafting Man can produce new plants by artificial methods that would not take place naturally. The most common methods are: Cuttings Graftings Cuttings A piece of stem with some leaves is taken from the parent plant. It is then placed in a suitable compost to allow it to form roots. Grafting A bud or shoot of a valuable plant is taken and joined to the developed root stock of a hardy plant. Explain the advantages to man of artificial propagation in flowering plants Artificial methods of propagating plants have many advantages to man: Large numbers of plants can be generated quickly The plants are all identical so desirable qualities can be maintained Seedless plants can only be grown by artificial propagation e.g. banana and seedless grapes Rare plants can be saved from extinction 6 Describe asexual reproduction by runners and tubers Some plants can reproduce asexually (without flowers or fertilisation). Asexual reproduction involves only one parent. Many plants have special structures that allow them to reproduce sexually. Runners Side shoots grow out from the parent plant. Buds form along the runner. These obtain food and water from the parent until they grow their own roots. Eventually they become detached from the parent. e.g strawberry, spider plant runner Tubers Underground food store that stores enough food over winter to start the growth of a new plant. Each new plant can then make its own food and form several tubers for the next winter. A shoot grows from an eye. Shoot forms leaves. food made by leaves is sent down to make new tubers. plant withers but tubers stay in soil until next year e.g. potato, dahlias, crocus. Describe what is meant by the term “clone” A clone is a group of cells or organisms that have all been produced asexually from the same single parent. This means that they are all genetically identical to one another. Describe the advantages of both sexual and asexual reproduction in plants Method of reproduction sexual asexual Advantage 2 parents mean that each plant shows variation from the rest so species would survive a disaster in the environment e.g. disease plants well distributed meaning less competition seeds stay dormant until conditions for growth are good Plants are all identical so good features will always be passed on Young plant can outgrow competitors as it receives food and water from its parent Only one parent is needed 7 Making Food Explain the need for transport systems in a plant Plants need transport systems as all parts of the plant need water (taken in through the roots) and food (made in the green parts of the plant). Plants therefore need transport systems to move these substances around. Describe the pathways of movement of water and food in xylem and phloem Xylem vessels carry water which is absorbed from the soil by the roots and is carried up to all parts of the plant. Phloem vessels carried dissolved food (sugars) from the leaves down to all parts of the plant that cannot make their own food e.g. roots, flower Describe the structure of phloem and xylem and identify other functions of the transport system Xylem and phloem are the two main transport systems. The two sets of tubes are found together in bundles. The bundles are called vascular bundles. The position of the vascular bundles in stems and roots is not the same. Xylem Xylem vessels are dead The end walls of the cells have disintegrated to form hollow tubes The side walls have become impregnated with rings of lignin, which strengthens the tubes Phloem Phloem cells are alive and consist of 2 types of living cells: sieve and companion cells. The end walls of the sieve cells have pores. Each tube cell has a companion cell. Companion cells provide the energy for the sieve cells. Food is transported through the pores from cell to cell in the form of dissolved sugar Other functions of the transport system Xylem transport minerals The tough lignified xylem tubes support the plant 8 State that plants take in carbon dioxide from the air through stomata which can open and close Plants take in carbon dioxide from the air through tiny pores on the surface of the leaves. These pores are called stomata. State that water vapour is lost through stomata Stomata open during the day and close at night Describe the external features and internal structure (epidermis, mesophylls, veins) of a leaf in relation to its function in gas exchange The leaf is the organ that plants use to make food by photosynthesis. Structure Epidermis Palisade mesophyll cells Spongy mesophyll cells Air spaces Veins Stomata Guard cells Function and other features Protection. Also transparent to let light through Site of most photosynthesis (cells contain many chloroplasts) Cells are tightly packed to absorb maximum light Photosynthesis (cells contain some chloroplasts) Have air spaces between them Diffusion of gases Contain xylem and phloem which transport water and food Allow gas exchange Control the size of the stomata 9 State that green plants make their own food which may be stored as starch Green plants make food in the form of sugar. This sugar can be used straight away or converted into the storage carbohydrate, starch. When a plant is left in the dark it uses up its stored food, this is called destarching. Describe the fate of carbon dioxide as structural and storage carbohydrates in plants and as energy sources The food that plants make is in the form of carbohydrates. Plants make carbohydrates by combining carbon dioxide from the air with water The simplest useful form of carbohydrate made is glucose. Glucose can be used as a source of energy or converted into: Storage carbohydrates e.g. starch or Structural carbohydrates e.g. cellulose in the plant cell walls or lignin in xylem. State that green plants convert light energy to chemical energy using chlorophyll Chlorophyll captures light from the Sun and converts it into chemical energy which is used to make glucose Describe the process of photosynthesis in terms of raw materials and products Photosynthesis is the process by which green plants use light energy to make food. Carbon dioxide + water raw materials light energy glucose + oxygen products chlorophyll Explain what is meant by a limiting factor and describe the main limiting factors in the process of photosynthesis A limiting factor is a factor that slows down a process because it is in short supply. Photosynthesis can sometimes be limited because certain factors are in short supply. Light Carbon dioxide Temperature can all act as limiting factors We can measure the rate of photosynthesis by counting the number of bubbles coming from an Elodea plant 10