Recombinant DNA Technology and Evolutionary Theories

Posted on Mar 16, 2025 in Geology

Recombinant DNA Technology

Recombinant DNA technology involves several key steps:

  1. Locating and Isolating the Gene: Restriction enzymes are used to cut DNA into fragments, isolating the desired gene.
  2. Choosing a Vector: A vector (plasmid or virus) is cut with the same restriction enzyme. The isolated DNA is joined to the vector DNA using DNA ligases, creating recombinant DNA.
  3. Introducing Recombinant DNA: The recombinant DNA is introduced into a host cell, creating a transgenic organism.
  4. Checking Gene Expression: Checks are performed to ensure the transgenic organism is producing the desired protein.
  5. Multiplication of Transgenic Organism: The transgenic organism divides, creating clones carrying the new gene.

Evolutionary Theories

Fixist Theories

Fixist theories propose that species were created by God in their present form and have not changed. Cuvier’s theory of catastrophism suggests that Earth experienced catastrophes like the great flood, leading to the extinction of many species. Fossils were considered remains of extinct species, not pre-existing forms of current species.

Evolutionary Theories

Several naturalists opposed fixism and catastrophism, proposing actualism and evolutionism.

Evolutionism

Evolutionism maintains that species undergo transformation, resulting in new species.

Actualism

Lyell’s actualism states that past events were caused by forces identical to those operating today. Changes in nature occur slowly, gradually, and continually (continualism), not through catastrophes.

Lamarck’s Theory

Lamarck proposed that spontaneous generation creates simple life forms, which evolve into complex organisms.

Organisms have an internal impulse to improve and become more complex. Environmental changes impact this process, leading to differential use of organs. The development or loss of organs acquired through use or disuse is inherited.

Example: Giraffes

  1. Giraffe predecessors fed on lower branches.
  2. When leaves ran out, they stretched their necks to reach higher branches.
  3. Stretching lengthened their necks through use.
  4. This lengthening was inherited, leading to modern giraffes over millions of years.