B13 Variation And Evolution

Question 1

What is variation?

Answer 1

Variation is the differences in the characteristics of individuals in a population

Question 2

Why will variation occur?

Answer 2

Variation may be due to differences in the genes inherited (genetic causes), the conditions in which organisms develop (environmental causes), or a combination of both genes and thr environment

Question 3

Natural selection

Answer 3

Natural selection is a process where organisms that are better adapted to an environment will survive and reproduce. This means that the advantageous alleles of this variant organism are passed on to offspring. Over many generations, the process of natural selection leads to evolution occurring.

Question 4

What is mutation

Answer 4

Mutation is a change in a gene or chromosome. It is a rare, random change in the genetic material and it can be inherited.

Question 5

Selective breeding

Answer 5

An artificial process in which organisms with desired characteristics are chosen as parents for the next generation.

Question 6

How does selective breeding work?

Answer 6

• Decide which characteristics are important enough to select.
• Choose parents that show these characteristics from a mixed population. They are bred together.
• Choose the best offspring with the desired characteristics to produce the next generation.
• Repeat the process continuously over many generations, until all offspring show the desired characteristics.

Question 7

What js genetic engineering?

Answer 7

A process of changing the structure of a particular gene, usually to remove defects.

Question 8

Principles of Genetic Enginerring

Answer 8

• Enzymes are used to isolate and ‘cut out’ the required gene from an organism, for example , a person
• The gene is then inserted into a vector using more enzymes. The vector is usually a bacterial plasmid or a virus.
• The vector is then used to insert the gene into the required cells, which may be bacteria , animal , fungi or plants
• Genes are transferred to the vells at an early stage if their development(in aimals, the egg , or very early embryo). They develop with new desired characteristics from other organisms.
• In plants m the desired genes are often inserted into meristem cells which are then used to produce identical clones of genetically modified plant.

Question 9

How are genes transferred?

Answer 9

Genes can be transferred to the cells of animals and plants at an early stgae of their development so they develop desired characteristics.

Question 10

Benefits of gentic engineering

Answer 10

-Improved growth rates of plants and animals
-increased food value of criops , as gentically modified (GM) crops ususally have much bigger yields than ordinary crops
-Crops can be designed to grow well in dry hot or cold parts of
the world
-crops can be engineered to produce plants that make their own pesticide or are resistant to the herbicides used to control weeds.