Topic 4 - Natural selection and Genetic Modification

• What theory did Charles Darwin and Alfred Wallace develop?


  Theory of Evolution by Natural Selection
• What does the theory: survival of the fittest state?


  individuals with traits best suited to their environment are more likely to survive and reproduce, contributing to the evolution of species over time. Traits happen as a result of mutations that change the allele of an organism which makes the beneficial characteristics beneficial over time.
• How does Bacteria provide evidence for evolution?


  Antibiotic resistance in bacteria demonstrates natural selection; resistant individuals survive antibiotic treatment, reproduce, and over time, the population becomes predominantly resistant, aligning with Darwin's theory. The resistant ones appear due to mutations that happen during frequent reproduction.
• What is a fossil?


  The preserved remains or traces of ancient organisms. They are typically found in rocks.
• How do fossils provide evidence for evolution?


  Fossils provide a record of past life forms, showing changes in species over time, supporting the concept of evolution by revealing transitional forms and the progression of life on Earth.
• Who is Ardi?


  Ardi is a fossil hominin species that is 4.4 million years old. He had long arms and short legs with a small brain.
• Who is L?


  Lucy is a Fossil Hominid that is 3.2 million years old. her legs and brain were larger than Ardi's
• what did Leaky discover?


  Fossil hominids that existed 1.6 million years ago which showed physical attributes similar to a human than an ape - proving evolution.
• Homo habilis (2.5-1.5 million years ago):

  • Made simple stone tools called pebble tools by hitting rocks together.
  • Used these tools to scrape meat from bones or crack bones open.
• Homo erectus (2-0.3 million years ago):

  • Sculpted rocks into shapes, producing more complex tools like simple hand-axes.
  • These tools were used for hunting, digging, chopping, and scraping meat from bones.
• Homo neanderthalensis (300,000-25,000 years ago):

  • Developed more complex tools, including evidence of flint tools, pointed tools, and wooden spears.
• Homo sapiens (200,000 years ago-present):

  • Used flint tools extensively, with pointed tools like arrowheads, fish hooks, and needles appearing around 50,000 years ago.
• State one method that the scientist could use to find the age of the stone tools.

  Carbon dating or looking at the different ages of rocks.
• The similarity in bone structure of the pentadactyl limb provides evidence that species with a pentadactyl limb have all evolved from a common ancestor (that had a pentadactyl limb).
• what is classification?


  Organising living organisms into groups.
• Genetic analysis has led to the suggestion of the three domains (Bacteria, Archaea, and Eukarya) instead of the five kingdoms. This shift reflects more accurate genetic relationships and molecular similarities.
• What are the 5 kingdoms?


  Animals, Plants, Fungi, Prokaryotes, protists
• what are the 3 class domains?


  Bacteria, Archaea, Eukarya.
• Using RNA sequencing, we can distinguish the difference between organisms that fall into the Eukaryotic and Archaic domains.
• what is selective breeding?

  Selective breeding is the process of intentionally choosing and mating organisms with desirable traits to produce offspring with those traits.
• Give an example of selective breeding:


  Breeding plants to produce bigger fruits.
• What are the advantages of selective breeding?


  Genetic variation and medical research
• What are the disadvantages of selective breeding?

  Reduced genetic diversity - results in inbreeding which causes genetic defects.

  There are fewer chances of resistant alleles being present due to the lack of genetic diversity which means that a new disease would be very harmful.
• What is tissue culture?


  The process of growing plant cells in a controlled environment outside of their natural environment. They are grown in an artificial growth medium.
• Plants produced in tissue culture are clones and are identical to the parent plant.
• what are the steps for undergoing the process of tissue culture?

  1. Sterilization:

  • Ensure a sterile environment.

  1. Tissue Selection:

  • Choose a healthy explant.

  1. Disinfection:

  • Sterilize the explant.

  1. Medium Preparation:

  • Prepare a nutrient-rich medium.

  1. Inoculation:

  • Place explant on the medium.

  1. Incubation:

  • Seal and incubate.

  1. Observation and Sub-culture:

  • Regularly observe and sub-culture for maintenance.
• Animal tissue culture is useful for medical research
• What is genetic engineering?


  genetic engineering is a process which involves modifying the genome of an organism to introduce desirable characteristics
• What is the process of genetic engineering?

  1. Restriction Enzymes:

  • Cut DNA at specific sequences, creating fragments with cohesive ends.

  1. Sticky Ends:

  • Single-stranded overhangs are created by restriction enzymes, aiding in precise DNA fragment connections.

  1. Ligase:

  • Join DNA fragments by sealing the sticky ends with ligase.

  1. Vectors:

  • Carrier molecules, often plasmids, are used to introduce foreign DNA into host cells.
• what are the advantages of genetic engineering?

  Improved crop yield, disease resistance, and the potential for medical advancements (genetically engineering bacteria to produce insulin).
• Prolonged exposure of insecticides to insects results in the development of immunity. Therefore, Farmers must use different types of insecticides to prevent this from happening.