B6 - Inheritance, Variation, and Evolution

• What is Environmental Evolution?

  Environmental Evolution is how the environment, including the conditions that organisms live and grow in, cause differences between members of the same species.
• What is genetic evolution?


  An organism's characteristics are determined by the genes inherited from their parents. these genes are passed on in sex cells. Most animals (and some plants) inherit genes from both their mother and father. The combining of the two parents' genes, causes genetic variation.
• What are mutations?

  Mutations are changes to the sequence of bases in DNA.
• What can mutations lead to?

  Mutations can lead to changes in the protein that a gene codes for. This can slightly alter the phenotype or create a completely new phenotype.
• What is the Theory Of Evolution?

  The Theory Of Evolution, is the belief that all of today's species have evolved from simple life forms that first started to develop over three billion years ago.
• What is meant by 'The Survival Of The Fittest'?

  Organisms with more suited characteristics for the environment are more successful competitors and would be more likely to survive. These are more likely to reproduce, and pass on the characteristics to their offspring. Over time, beneficial characteristics become more common, and the specie changes (evolves).
• What is speciation?

  Speciation is when populations of the same species changes enough to become reproductively isolated, meaning they cant interbreed to create fertile offspring.
• Why do species become extinct?

  Environment changes too quickly.A new predator kills them.A new disease kills them.they cant compete with another species for food. A catastrophic event happens that kills them.
• What 3 conclusions did Mendel come to?

  1. Characteristics in plants are determined by "hereditary units".2. They are passed onto offspring unchanged (one from each parent)3. Hereditary units can be dominant or recessive.
• What happened in the late 1800's regarding cells?

  Scientists became familiar with chromosomes, and how they behaved during cell division.
• What happened in the early 20th century regarding genes?

  Scientists realised there were striking similarities in the way that chromosomes and Mendel's "units" acted. They later proposed that these "units" were found on chromosomes (genes)
• What happened in 1953 regarding genes?

  Structure of DNA was determined, allowing scientists to find out exactly how genes worked.