Biology Crossword

4. the appearance of apparently similar structures in organisms of different lines of descent
5. Random change in allelic frequencies in a population
8. Process in which individuals with average traits are removed, creating two populations with extreme traits
11. Occurring after formation of a zygote

1. Two or more species having a close ecological relationship evolve together such that one species adapt to the changes of the other, thereby affecting each other's evolution
2. Most common form of natural selection in which organisms with extreme expressions of a trait are removed
3. Occurring before breeding; producing a fertilized egg, or zygote
6. Random effect that can occur when a small population settles in an area separated from the rest of the population and interbreeds, producing unique allelic variations
7. Diversification of a species into a number of different species, often over a relatively short time span
9. Shift of a population toward an extreme version of a beneficial trait
10. Process in which a large population declines in number, then rebounds
12. Change in the frequency of a trait based on competition for a mate
13. Occurs when a population divided by a geographic barrier evolves into two or more populations unable to interbreed
14. States that allelic frequencies in populations stay the same unless they are affected by a factor that causes change
15. Occurs when a species evolves into a new species in an area without a geographic barrier