Descent with Modification in Darwin's Book

Genetic Engineering

• Growth hormones and insulin are produced by DNA technology.
• Tissue plasminogen activator (PA) is produced by bacteria through DNA technology to prevent blood clots and treat stroke patients.

Genetically Modified Organisms

• The objective of genetic modification is to enhance favorable characteristics and ensure safety for human consumption.
• Examples of genetically modified organisms include Bt corn, golden rice, FlavrSavr tomato, and Bt peanut.

Gene Analysis

• The polymerase chain reaction enables scientists to make numerous copies of a DNA segment.
• This allows for in-depth research on the gene's function in an organism.

Mechanism of Evolution

• Natural selection, mutation, genetic drift, DNA recombination, non-random mating, and gene flow are mechanisms that drive evolution in populations.
• Charles Darwin and Alfred Wallace independently developed the theory of evolution by natural selection.

Gene Therapy

• Gene therapy is a form of treatment used to cure conditions arising from defective or absent genes.
• The affected gene is inserted into a plasmid and reintroduced to target cells, allowing the gene to perform its functions.

Natural Selection

• The struggle for existence is a central idea in Darwin's theory of evolution, inspired by Thomas Malthus' essay on population growth and food supply.
• Individuals with traits better suited to their environment are more likely to survive and reproduce, leading to the gradual accumulation of advantageous traits in a population over time.

Adaptations

• Adaptive traits, such as those resulting from natural selection, can be processes or states.
• Not all traits are a result of adaptation; examples include the color of blood (due to hemoglobin's chemical structure) and the function of feathers as flight (an example of exaptation).

Descent with Modification

• Descent with modification is the process used by natural selection, where traits are passed down from generation to generation and sometimes undergo changes or modifications over time.
• Darwin described this process in his book "The Origin of Species".

Peppered Moths

• The peppered moth case in England during the Industrial Revolution is a classic example of natural selection in action.
• The population shifted from predominantly light-colored moths to dark-colored moths due to natural selection favoring those with traits providing better camouflage and increased survival.