Across
- 5. A fertilized egg, formed by the fusion of male and female gametes
- 8. When homologous chromosomes exchange alleles during meiosis, which increases genetic variation.
- 13. The allele that is always expressed (shows up as a trait) if it is present in the genotype.
- 14. The random arrangement of homologous chromosomes when lining up and separating during meiosis.
- 16. The set of all the alleles present in a population.
- 18. A process for breeding a specific required trait.
- 19. A permanent change in the base sequence of DNA that causes variation.
- 20. A type of cell division which produces identical body cells for growth and repair, or to produce clones through asexual reproduction.
- 21. When a population's size is dramatically reduced, leading to a loss of genetic diversity and altering allele frequencies in the surviving individuals.
Down
- 1. An event that drastically reduces the size of a population.
- 2. The process by which beneficial phenotypes in a population tend to be preserved while unfavourable phenotypes tend to be lost.
- 3. A group of individuals that can breed to produce fertile offspring.
- 4. The fusing (joining) of a male and female gamete to form a zygote.
- 6. A change in allele frequency within a population due to a random event.
- 7. A type of cell division which produces egg and sperm cells (gametes) with half the number of chromosomes of the parent cell.
- 9. The change in the gene pool within a population over many generations.
- 10. The transfer of alleles from one population to another, usually by migration.
- 11. An alternative version of a gene (with a slightly different order of base pairs).
- 12. A body cell.
- 15. A form of producing offspring involving the fertilization of two gametes from two parents, producing variation in the offspring.
- 17. Environmental factors that that reduce or increase the reproductive success of individuals with a particular phenotype over another.