Natural selection and Genetic modification

• What did Darwin do?

  Darwin developed the theory of evolution through natural selection, by observing variation in members of the same species. This variation lead to individuals with better suited characteristics to the environment, allowing them to thrive more.he also noticed that characteristics can be passed off to offsprin.
• What did Wallace do?

  He also came up with the theory of evolution, independently of Darwin. Wallace provided evidence to evolution like warning colours of a butterflies wings to deter predators.
• how does evolution effect modern biology?

  ~affects how we classify organisms

  ~antibiotic resistance

  ~conservation
• how do you classify living organisms using the five kingdom classification system?

  First living things are divided into five kingdoms:

  animals, plants, fungi, prokaryotes, protists

  They are then divided into smaller sub groups based on different features:

  phylum, class, order, family, genus, species
• how do we classify organisms based on DNA and RNA?

  Look at DNA and RNA to see how closely relates organisms are and then out them into these groups:

  Archaea = look similar to bacteria but have different DNA and RNA sequences

  Bacteria = contains true bacteria like Ecoli

  Eukaryotes = contains a broad range of organisms like plants, animals, fungi etc

  These are then subdivided into smaller groups using the five kingdom classification system
• what are the key facts about ardi?

  Ardi is a nickname for Ardipithecus ramidus, a hominin species that lived around 4.4 million years ago. Ardi has features that are more like apes than humans. For example the structure of Ardis feet shows that we used to climb trees, and Ardis arms are longer than her legs, as well as having the same brain size of a chimpanzee. However her leg structure shows that we still used to walk upright and her hands show that we didn’t use our hands to help us walk (unlike apes).
• what are the key facts about the fossil Lucy?

  Lucy is an Australopithecus, 3.2 million years old. Lucy had arched feet more adapted to walking than climbing, and her arms and legs size were becalming more like a humans but still had some resemblance of an apes, her brain was larger than ardis but still similar to that of an apes
• what are the key facts of Turkana boy?

  He was 1.6 million years old, had short arms and long legs (more human like), his brain was larger than Lucy’s and more like a human sized brain, the structure of his feet and legs were better adapted to walking upright
• What’s a pentadactyl limb?

  A limb with five digits.

  For humans it’s our hand but for a bat it’s the wing. This shows that many different species has this limb (mammals, amphibians, etc), this similarity in bone structure provides evidence that we all evolved from one common ancestor
• what are the disadvantages to selective breeding?

  Inbreeding, reduced genetic diversity, lessens variation
• what are the pros to selective breeding?

  Increased desired traits, important in agriculture.
• how is genetic engineering performed?

  1~ The DNA you want to insert is cut out with a restriction enzyme. The vector DNA is then cut open using the same restriction enzyme

  2~ the sticky ends of both of the separate DNA are put together using ligase enzymes, this creates recombinant DNA

  3~ the recombinant DNA is inserted in a different cell, eg bacteria

  4~ these cells can now use this to make the protein you want, eg the bacteria now containing the code for human insulin, can be grown in huge numbers due to the rate at which bacteria reproduces, passing on that gene.
• what are the uses of genetic engineering in agriculture?

  Increased crop yield, pest resistance, disease resistance, improved nutritional content. However there are concerns about whether these modified crops are safe to eat, and about weeds picking up on these modified genes.
• what are the uses of genetic engineering in medicine?

  Animals can be genetically modified for human organ transplants, you can use animals to create the antibodies needed (eg insulin). However most genetically modified embryos don’t survive, or have health complications later in life.
• How can you create plant tissue using tissue culture?

  1~ choose the plant you want to clone based on its characteristics

  2~ remove several small pieces of tissue from the parent plant, preferably from the meristem

  3~ grow the tissue in a growth medium containing nutrients and growth hormones. This done under aseptic conditions to prevent other organisms growing that may harm the plant

  4~ as the tissues produce shoots and roots they can be moved to potting compost to continue growing.
• How can tissue culture be used on animals?

  1~ a sample of the tissue you w at to study is extracted from the animal

  2~ the cells in the sample are separated from each other using enzymes

  3~ they are placed in a culture vessel and bathed in growth medium, containing all the nutrients they need

  4~ after several rounds of cell division, the cells can be split up again and placed into several vessels, to encourage further growth

  5~ once the tissue culture has been grown, it can be stored for future use
• Why would we genetically modify organisms?

  ~a crop can be genetically modified to kill insect pests, this is done by taking a gene that produces a toxin that kills pests and inserting it into the plant

  ~ GM crops can be grown to help fight vitamin deficiencies or increase crop production (by modifying them to be able to survive in extremely hot or dry places)
• what are the drawbacks to GM crops?

  ~countries can become dependent on companies that make these

  ~many can’t afford it due to poverty

  ~not even GM crops can survive poor soil quality