Sled Dogs and Evolution

2. Where sled dogs from North America originated.
4. Two incipient species that no longer reproduce.
9. Where evolutionary biologist Robert Wayne believes dogs originated.
10. An evolutionary process whereby artificial selection is applied by humans.
11. Where geneticist Peter Savolainen believes dogs originated.
12. A new type of sled dog used in sprint racing.
15. The first to have pondered over the origin of dogs.
18. Domestic dogs as Linnaeus would write.
19. A type of speciation where a portion of a population occupies a new niche.
21. A new type of sled dog used in distance racing.

1. In the 70’s, scientists believed dogs originated from here.
3. A type of evolution where two or more species independently develop a similar adaptation.
5. Imperative to the human-dog relationship.
6. An event that drastically reduces the size of a population.
7. The most ancient breed of sled dog.
8. The love hormone.
10. The very first organism to be domesticated.
13. A cross between two species.
14. Descent with modification.
16. A characteristic produced by natural selection.
17. The ancestor of dogs.
20. An igneous rock that provided evidence of dog sledding.