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bio 3/4
changes in the genetic makeup of a population
| Question | Answer |
|---|---|
| What is a mutation? | Changes in DNA in a gene or chromosome, that are spontaneous, or that arise from mutagens. Results in a genetic variation between species and individuals. |
| What are point mutations? | A mutation that alters, adds or removes a single nucleotide. |
| What are the three types of point mutations? | Silent adds a new codon for the same amino acid. Missense is when a new amino acid is produced. Nonsense is the creation of a stop codon; severe effects are seen. |
| What is a frameshift mutation? | A mutation where one or two nucleotides are added or removed from a nucleotide sequence, altering every codon in that sequence from that point onwards. |
| What is a block mutation? | A mutation that affects a large section of a chromosome, typically multiple genes. This occurs in meiosis. |
| What are the different types of mutations? | Duplication; section is replicated. Deletion; section of chromosomes is removed. Inversion; section of chromosome is rotated 180 degrees. Insertion; chromosome breaks off and reattaches to a different chromosome. Translocation; exchanged with another. |
| What is a chromosomal abnormality? | Easily detectable by karyotyping. Includes aneuploidy and polyploidy. |
| What is the difference between an aneuploidy and polyploidy? | Aneuploidy is caused by homologous chromosomes not separating during meiosis, either an extra or missing chromosome. Polyploidy is an error in meiosis that results in diploid gametes. |
| What is an environmental selection pressure? | If a particular phenotype gives an organism a survival advantage, that phenotype and the gene/alleles that control it will persist. A selection pressure is the conditions or factors that influence allele frequencies. |
| What is natural selection? | Individuals with the most advantageous phenotypes have an increased chance of producing fertile offspring, passing them on to the next generation. |
| What is gene flow? | Migration of individuals joining population from a different gene pool. |
| What is genetic drift? | Allele frequencies changing over time as a result of chance events/effects (small populations the most). |
| What is the bottleneck effect? | A sharp reduction of a population gene pool because of an environmental or human-caused activity, and the impact that it will have on the remaining population |
| What is the founder effect? | A small group of individuals from a larger population, moves to a new location and establishes a new population. New population is not reflective of original population. |
| What are the biological consequences of such changes in terms of increased or reduced genetic diversity? | Reduced genetic diversity results in low chances of survival, higher vulnerability to environmental change and leaves a risk of extinction. |
| What is allopatric speciation? | When a population is divided by a geological barrier preventing subpopulations from interbreeding. Spatial isolation prevents gene flow (genetic isolation). |
| What are examples of prezygotic isolating mechanisms? | Geographical isolation, ecological isolation, temporal isolation, behavioural isolation, structural/morphological isolation and gamete mortality. |
| What is sexual selection? | A mode of natural selection where members of one biological sex choose mates of the other sex to mate with. |
| What are examples of postzygotic isolating mechanisms? | Prevent zygotes of two different species from developing into a fertile adult. Hybrid is an offspring resulting from interbreeding between individuals from different species. Examples include, hybrid in viability, hybrid zygote, and hybrid sterility. |
| What is selective breeding? | Artificial selection, humans select desired traits and interbreed organisms with these traits |
Created by:
lucyokane
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