Evolution Crossword George

3. species that were once similar become increasingly different
5. a basic unit of classification and taxonomy
7. structures or attributes that have lost function
9. a sharp decline in population size after an environmental event
10. variation in frequency of genotypes due to chance
13. speciation caused by human intervention (cows, chickens, dogs)
16. organisms of this species are currently alive
17. selective breeding is an example of this
18. loss of genetic diversity due to a small breeding population
21. the theory that life originated from microbes that traveled to Earth from space.
23. a condition in which cells have more than one pair of chromosomes
24. refers to when there are no living organisms in a species

1. an organism's observable traits
2. "survival of the fittest"
4. occurs when populations are isolated, creating speciation among the smaller groups
6. occurs when two or more organisms affect each other's evolution through natural selection
8. a cyanobacteria that is Earth's earliest fossil evidence of life.
11. Researched finch populations
12. the hypothetical conditions present on Earth that allowed for life to begin.
14. model of evolution that involves slow, steady transformation of species
15. similarity of genome, physiology, or structure of an organism based on common ancestry
19. a theory that holds most evolutionary changes are on the molecular level and are due to random genetic drift that is selectively neutral
20. remains of an organism encased in rock
22. different species evolve to have similar traits