Natural Selection And GM Flashcards
What is variation and what causes it?
Variation is differences between individuals of the same species. It is caused by genetic factors (mutations, different alleles) and environmental factors.
What is meant by natural selection?
Natural selection is the process where organisms with the most beneficial characteristics are more likely to survive and reproduce, passing on these genes.
How do mutations lead to evolution?
Mutations create variation. If a mutation gives an advantage, it may be passed on through natural selection, gradually changing the species.
What is evolution?
Evolution is the gradual change in the inherited characteristics of a population over time through natural selection.
How did Darwin contribute to the theory of evolution?
Darwin proposed the theory of evolution by natural selection in his book On the Origin of Species, based on observations of species in the Galapagos Islands.
Why was Darwin’s theory controversial?
It conflicted with religious views, lacked explanation for inheritance (genetics not known), and lacked sufficient evidence at the time.
What is selective breeding?
Selective breeding is when humans breed plants or animals for specific traits, such as disease resistance or high yield.
What are the disadvantages of selective breeding?
Reduces biodiversity and means species are more susceptible to disease
What is genetic engineering?
Genetic engineering is altering an organism’s DNA to include a gene from another species to give a desired characteristic.
How is genetic engineering carried out?
- Isolation of the gene: The gene that codes for the desired characteristic is identified and isolated from the DNA of the donor organism using restriction enzymes creating “sticky ends” for the gene.
- Insertion into a vector:The vector is also cut using the same restriction enzyme leaving “complementary sticky ends” The gene is then inserted into the vector, usually a plasmid (a small circular DNA molecule found in bacteria) or a virus. This vector will carry the gene into the target organism.
- Inserting the gene into the target organism: The vector is used to transfer the gene into the cells of the target organism. This is often done at an early stage of
development (e.g., in plant embryos) so the gene is present in all cells as the organism grows. - Expression of the gene: Once inside the organism, the gene is expressed, and the organism displays the desired characteristic (e.g., resistance to pests or increased growth rate).
- Selective breeding (optional step): Organisms that successfully express the gene may be bred to produce more organisms with the same genetic modification.
What are the benefits of genetic engineering in agriculture?
GM crops can have increased yield, resistance to pests and diseases, and tolerance to drought.
What are the concerns about genetic engineering?
Possible long-term effects on health and the environment, ethical concerns, and reduced biodiversity.
What are the ethical issues surrounding genetic engineering?
Some people believe genetic modification is unnatural or interferes with nature. There are concerns about long-term effects on health, the environment, and reduced biodiversity. There are also religious and moral objections.
What is tissue culture and how is it used in GM?
Tissue culture is a method of growing cells or tissues in a nutrient medium. It is used to clone genetically modified plants or to produce identical cells with desired traits.
