Variation within species & mutations and selective advantage
This document discusses genetic variation within species and the role of mutations. It defines key terms like species, genes, and genetic variation. Genetic variation arises from factors like independent assortment, crossing over, and mutations during DNA replication or meiosis. Mutations are a permanent change in genetic material and are the only source of new genetic variation. Mutations can occur naturally during DNA copying or be caused by environmental mutagens like radiation, viruses, transposons, or chemicals. Mutations may result in cell death, malfunction, or sometimes provide a selective advantage that improves an organism's chances of survival, especially in a changing environment. Examples of selective advantages are provided for Daphnia and bacteria.
Variation within species & mutations and selective advantage
- 1. Variation Within Species & Mutations and Selective AdvantagePatrick Zisser and Peter Dyloco
- 2. A group of organisms that can interbreed in nature and produce fertile offspringSpecies
- 3. A part of a chromosome that governs the expression of a trait and is passed on to the offspring; it has a specific DNA sequenceGene
- 4. What is genetic variation?
- 5. Genetic VariationThe different allele combinations in a species that cause differently expressed phenotypes and genotypes
- 6. Cause of Genetic VariationOrder of bases in nucleotides
- 8. Factors in Genetic VariationTotal variety of genetic informationIndependent AssortmentCrossing over/random segregationMutationsGene flow
- 9. Genetic Diversity: Total Variety of Genetic InformationVS.
- 10. A permanent change in the genetic material of an organism, the only source of new genetic variationMutation
- 12. Causes of MutationNatural:Errors during DNA replication or meiosisEnvironmentalMutagensRadiationVirusesTransposonsChemicals
- 13. Natural: occurs during DNA replication or meiosis; when DNA is copied and before cell divides (S phase) 175 mutations vs. parent
- 14. Environmental: Mutagens - Radiation
- 15. Environmental: Mutagens - Viruses
- 16. Environmental: Mutagens - TransposonsA segment of DNA that can become integrated at many different sites along a chromosome (especially a segment of bacterial DNA that can be translocated as a whole)
- 17. Environmental: Mutagens - Chemicals
- 18. Gene FlowThe net movement of alleles from one population to another due to the migration of animals
- 20. Cell deathCell malfunctionSelective advantage
- 21. Cell Death and Malfunction
- 22. Mutations in somatic cell disappear after death of organismOnly mutation in gamete cell may pass trait as new alleleNote
- 23. A genetic advantage that improves an organism's chance of survival usually in a changing environmentSelective Advantage
- 26. End.
Editor's Notes
- #25: In some environments, mutations that were once neutral or a disadvatage may become beneficial. This is called a selective advantage. it gives a genetic advantage to the organism over its competitors. For example look at the water flea Daphnia. it normally lives in water that is 20 degrees celsius and it cannot survive in water 27 degrees celsius or higher. But some mutations can survive in temperatures between 25 and 30 degrees celsius.
- #26: Other organisms like bacteria viruses and many insects reproduce very very rapidly. Some bacteria populations can double in under ten minutes. In populations that reproduce that quickly random mutations can be the key to survival. If the organism lives long enough to reproduce and pass on the genetic information then in time the whole population might gain the selective advantage. One mutation can mean the survival of an entire poulation.