Across
- 4. A phrase that describes natural selection. Fit as opposed to unfit
- 6. The evolution of a new species
- 8. Natural selection that favors the average individuals in a population
- 10. Human select useful variations or traits they desire in organisms
- 11. The change in allelic frequencies caused by a chance event
- 12. When members of a population can no longer mate and produce fertile offspring
- 15. When species that were once similar to an ancestral species diverge
- 17. Natural selection that favors either extreme of a traits variation
- 18. A population in which the frequency of alleles remains the same
- 19. Gradual change in a species through adaptations over time.
- 20. Physical evidence of an organism that lived long ago that scientist use to study the past.
- 22. The traits that help an organism survive in a particular environment are “selected’ in natural selection
Down
- 1. A structure in present-day organisms that no longer serve a purpose
- 2. Natural selection that favors one of the extreme variations of a trait
- 3. Provide evidence of evolution from a common ancestor, arm of human and wing of a bat are examples.
- 5. Speciation occurs rather quickly and in rapid bursts
- 7. All of the alleles of a population’s genes
- 9. When a physical barrier separates a population
- 13. Structures that do not have a common evolutionary origin but are similar in function.
- 14. When distantly related organisms evolve similar traits
- 16. The idea that species originate through a gradual change in adaptations
- 21. Well supported explanation of phenomena that has occurred in the natural world