Evolution - B1

Particular genes or accidental changes in the genes of plants or animal may give them characteristics that enable them to survive better.
1. over time this may result in entirely new species
there are different theories of evolution
1. DARWIN'S THEORY
  1. THE MOST WIDELY ACCEPTED
  2. natural selection
    1. states that all species of living things have evolved from simple life forms that first developed more than 3 billion years ago
    2. this is a theory because of the timescales involved it is unlikely to ever be proven
    3. evolution occurs via this process
      1. - individuals within a species may show a wide range of variation because of differences in their genes
      2. - individuals with characteristics most suited to the environment are more likely to survive and breed successfully
      3. - those genes are responsible for the survival characteristics are then passed down to the next generation
  3. many people refused to accept his theory because:
    1. - it was a conflict with religious views that God had created the universe and all creatures in it
    2. - there was insufficient evidence to support the theory
      1. Darwin had developed his ideas from finches on the Galapagos islands; little research had taken place
    3. - the mechanisms of inheritance and genes were not known
2. LAMARCK'S THEORY
  1. worked before Darwin's
  2. based on the idea that changes occur in an organism during its lifetime can be inherited
    1. in the vast majority of cases, this type of inheritance cannot occur
  3. Lamarck thought herons had evolved long legs because they stretched their legs to stay dry, as shown
    1. they would then pass on these characteristics to their offspring
CLASSIFICATION
1. evolution and patterns of change can be studied efficiently only if organisms are carefully defined and their relationships understood
  1. living organisms are classified into:
    1. ANIMALS
    2. PLANTS
    3. MICROORGANISMS
MUTATIONS
1. = *random genetic alterations
2. they can cause an extreme change in the characteristics of an organism
3. if the mutation is coupled with a change in the environment... there can be relatively rapid change in that species

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Evolution - B1

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	Creado por Georgia Freeman hace más de 10 años