Please enable JavaScript.

Coggle requires JavaScript to display documents.

Year 9 science (Biology (9B: Plant growth (Reactions in plants (Aristotle,…

- - - - For a plant to grow large, it needs to be well looked after and given all the resources that it needs, such as additional light, water, warmth and mineral salts
      - An organisms surroundings are its environment
      - In all environments there are environmental factors that can change the organism, such as other organisms and non-living factors like temperature and the amount of light. These are known as physical environmental factors
      - The features of an organism are its characteristics
      - The difference between the characteristics of organisms are known as variation
      - Environmental variation is variation caused by an organism’s environment
      - In humans, examples of environmental variation include scars and hairstyles
      - Continuous and discontinuous
        
        Pumpkins for example, can have a large spread of different sizes
        
        Variations that can have any value between two points is called continuous
        
        Variation that can only have a value from a limited set of possible variables is discontinuous
      - Classification
        
        Classification is sorting organisms into groups
        
        The smallest group of classification is called a species
        
        Members in the same can reproduce with each other, and their offspring will also be able to reproduce
        
        Sometimes environmental variation can make classification difficult . In 2003 some ancient human bones were discovered on Flores island
        
        These bones were barely 1m tall - much shorter than adult humans. Some scientists think that the bones were from our species of human but had an iodine deficiency in their diet so they did not grow much. However, other scientist think that they were from a different, now extinct species
  - - - Aristotle, a Greek scientist, thought that plants ate soil, using their roots to suck it up. Some other people believed this until Jan Bapista van Helmont did an experiment
      - He planted a mall tree and gave it only water, whilst watching it grow for 5 years. He measured the masses of the pot, soil and the tree before and after the 5 years
      - The mass of the tree greatly increased, but the mass of the plant and soil was almost the same
    - - Fertilisers
        
        They contain mineral salts, such as potassium, phosphate and nitrates
        
        Farmers use artificial or natural ones such as manure.
        
        Microorganisms break down the manure and let out their mineral salts
      - Pesticides
        
        Pesticides kill pests (organism that damage crops)
        
        Insecticides kill insect pests
        
        Herbicides (weedkillers) kill weeds, which compete with the crop plants for water, light and mineral salts
      - Varieties
        
        A variety is a group of plants that have been bred to have certain characteristics.
        
        Some differences between varieties are not easy to see
        
        Different varieties are sometimes bred with each other to produce offspring that hopefully have the characteristics of both breeds. This is cross-breeding and is one way of creating a new variety.
        
        New varieties are also created using selective breeding. This is when only plants with certain characteristics are used to breed.
        
        Selective breeding is why carrots today are orange
    - - Clearing land (to make space for crops and machinery) destroys habitats, reducing populations of organisms
      - Fertilisers
        
        Fertilisers can wash into rivers and lakes. The phosphates and nitrates cause fast growth of algae and plants, which block out light causing a lot of them to die
        
        As decomposers break down the dead material, they use up oxygen in the water, causing fish to die
      - Pesticides
        
        Insecticides can kill helpful insects that eat pests or pollinate plants
        
        Some insecticides are persistent this means they do not break down in the environment
        
        Predators in the food chain may eat many animals containing small amounts of insecticides meaning that the top predator gets a large amount of the substance, which may harm it.
        
        Neonicotinoid insecticides make flowering plants poisonous for most the growing season
- - - - ● putting more particles into the container (so there will be more collisions with the container walls each second).
      - ● heating the gas (so the particles move faster, hitting the walls harder and more often).
      - ● reducing the volume of the container (so the particles do not have as far to go between the walls and so collide with the walls more often).
  - - - ● increasing the number of coils of wire
      - ● increasing the size of the current (by increasing the voltage)
      - ● using an iron core.
    - - ● increasing the size of the current
      - ● increasing the strength of the magnetic field
      - ● increasing the number of turns of wire on the coil.