Topic 4 bio gcse edexcel

• Alfred Russel Wallace


  A scientist that came up with the idea of natural selection, independently of Darwin. Although his proposed mechanism differed, his observations provided further evidence to support the theory.
• Antibiotic-resistant bacteria


  Bacteria that mutate to become resistant to an antibiotic, survive and reproduce very rapidly, passing on their antibiotic resistance.
• Archaea


  One of the three domains. It consists of primitive bacteria existing in extreme environments.
• Ardi


  A 4.4-million-year-old female hominid fossil that shows phenotypic traits encompassing characteristics of both humans and apes.
• Bacillus thuringiensis (Bt)


  A soil-borne bacterium which secretes a toxin that kills insect larvae. The gene for toxin production in Bt can be introduced into the DNA of crop plants to provide insect resistance.
• Bacteria


  One of the three domains that consists of true bacteria.
• Biological control


  The introduction of a new organism (often a predator) into an ecosystem to control a pest or pathogen.
• Carbon-14 dating


  Estimating the age of carbon-containing material that is found in or alongside archeological remains in order to determine their age.
• Charles Darwin


  The scientist who developed the theory of evolution by natural selection.
• Classification


  The organisation of organisms into groups based on their characteristics and structure.
• Competition


  When different organisms compete for the same resources (e.g. light, water, mates, territory) in an ecosystem. This limits population size and stimulates evolutionary change.
• Eukarya


  One of the three domains that consists of all eukaryotic organisms.
• Evolution


  The gradual change in the inherited traits within a population over time. Occurs due to natural selection.
• Fertilisers


  Natural or artificial materials that are added to soils to provide essential nutrients and improve plant growth.
• Five kingdom classification system

  The classification of organisms into five major kingdoms: Animalia, Fungi, Plantae, Prokaryotae and Protoctista.
• Fossils


  The remains of dead organisms found in rocks which are millions of years old.
• Genetically modified (GM) organism


  An organism that has had its genome altered.
• Genetic engineering


  The modification of the genome of an organism by the insertion of a desired gene from another organism, enabling the formation of organisms with beneficial characteristics.
• Genome


  The complete genetic material of an organism.
• Ligase


  An enzyme that joins the sticky ends of the DNA and vector DNA forming recombinant DNA.
• Lucy


  A 3.2 million year old female hominid fossil exhibiting more human-like phenotypic traits than 'Ardi'.
• Mutation


  A random change in the base sequence of DNA which may result in genetic variants. Mutations may be beneficial, damaging, or neutral.
• Natural selection


  The process by which the frequency of advantageous traits passed on in genes gradually increases in a population over time.
• Alfred Russel Wallace


  A scientist that came up with the idea of natural selection, independently of Darwin. Although his proposed mechanism differed, his observations provided further evidence to support the theory.
• Pentadactyl limb


  A limb with five digits present in animals, birds, reptiles and amphibians. It provides evidence for the evolution of species from a common ancestor.
• Antibiotic-resistant bacteria


  Bacteria that mutate to become resistant to an antibiotic, survive and reproduce very rapidly, passing on their antibiotic resistance.
• Archaea


  One of the three domains. It consists of primitive bacteria existing in extreme environments.
• Recombinant DNA


  A combination of DNA from two different organisms.
• Ardi


  A 4.4-million-year-old female hominid fossil that shows phenotypic traits encompassing characteristics of both humans and apes.
• Restriction enzymes


  Enzymes that cut DNA molecules at specific sequences, creating sticky ends.
• Bacillus thuringiensis (Bt)


  A soil-borne bacterium which secretes a toxin that kills insect larvae. The gene for toxin production in Bt can be introduced into the DNA of crop plants to provide insect resistance.
• Richard Leakey


  A scientist that discovered many hominid fossils on an expedition to Kenya, including the 1.6-million-year-old fossil 'Turkana Boy' which showed traits comparable to that of modern-day humans.
• Bacteria


  One of the three domains that consists of true bacteria.
• Biological control


  The introduction of a new organism (often a predator) into an ecosystem to control a pest or pathogen.
• Selection pressures


  Environmental factors that drive evolution by natural selection and limit population size, e.g. competition, predation and disease.
• Carbon-14 dating


  Estimating the age of carbon-containing material that is found in or alongside archeological remains in order to determine their age.
• Selective breeding


  The process by which humans artificially select organisms with desirable characteristics and breed them to produce offspring with desirable phenotypes.
• Charles Darwin


  The scientist who developed the theory of evolution by natural selection.
• Classification


  The organisation of organisms into groups based on their characteristics and structure.
• Sticky ends


  The staggered cut formed by restriction enzymes in double-stranded DNA.