Do humans have different breeds?
The concept of "breed" does not have biological relevance, such as "species", "sub-species" or even "race". Furthermore, as the name implies, it is man-made. People isolate traits they consider desirable in an animal or a plant by selective reproduction, and create breeds. It is widely seen in attempts to enhance "varietals" in food sources such as grains or livestock, and also when humans wish to create variants of living species for whim, self satisfaction, or commercial purposes, like some breeds of dogs and cats. Obviously, breeding can be applied to humans, as attempted in the US, Nazi Germany and other countries like Sweden through the profoundly unethical concept of eugenics. What human does naturally have are "races", such as african, mongoloid, caucasian, etc. They arise from evolutionary adaptations over milennia. Speciation is when an entirely new species arise. It happens when similar populations become isolated from one another for many centuries. If conditions vary in the two locations and the species undergo an evolutionary divergence, they will become less alike until, over eons, they will no longer be able to reproduce among themselves with viable offspring. Thus a new species is born.
What kind of dog is in the aptitude test in Divergent?
If you mean this one: it’s a Tervuren.
Why have dogs evolved into such a wide contrasts of breeds when humans have remained broadly similar?
Because Pure Bread Dogs are genetic monsters. Don’t take it from me. Take it from another Adam, in the video below. But just to summarize, Humans forced dogs to in-breed, as in incest. This inbreeding is used to concentrate genetic variations into the breed. Unfortunately, it also concentrates mutations that can be detrimental as well. If you put all those genetic variations together, you get a mutt. Mutts can be nice pets because there is less chance to inherit a genetic disease common to their breed.By contrast, learned beauty standards within humans will hamper anyone whose genes vary too far from common standards of beauty. I mean, except for xenophiles.Isn’t this beautiful? I think so. But to get a brood of humans all with this same trait, it would involve a lot of incest, and maybe only occasionally anything else. Genes are complex. Adding people in who don’t have some expressed trait is likely to drop the chances of it being passed to their offspring way below half. Generally, genes work together. Even if not this specific trait, there are many traits that only happen when several genetic variations appear together.Anyway, incest has been quite frowned upon for a while. Even if it’s not, people are generally free to marry people who don’t look all that similar. While history is spotted with inbreeding nobility looking to keep the wealth within the family, marriage historically was used to create strong cross-family bonds and alliances, which granted access to resources that were otherwise unavailable. This meant marrying outside the family, and by extension, far-flung gene transfers. So that’s why humans didn’t really concentrate into breeds.
Will my dogs hurt my goats in the same pen?
I've been raising goats since 1999. I have over 100 of them in my herd. The breeds of dogs that have attacked and killed goats in my herd: Chow Chow German Shepard Pit Bull Mastiff Rottweiler Golden Lab Attacks, but actual kills prevented: Australian shepards Healers Now before you think I hate dogs, here's a list of dog breeds we have owned before: Chow Chow English Mastiff Alaskan Malmute Springer Spaniel/Pointer cross Black Lab Rott/german shep/mastiff cross Karlian Bear Dog We have Great Pyrenees that live with our goats 24/7 now. I would not advise putting your dogs in with your goats. Hate to say it, but you made the titanic mistake of allowing your dogs to chase your goats. Your dogs ARE hunting breeds, with all the instincts that hunting breeds have. They will kill your goats, or serriously wound them, if given the chance. Experience with the breeds you've owned, and with goats tells me what you are thinking about doing is a huge no-no. ~Garnet Permaculture homesteading/farming over 20 years Raising meat goats since 1999
What are anagenesis and cladogenesis?
Anagenesis, also known as "phyletic change," is the evolution of species involving a change in gene frequency in an entire population rather than a cladogenetic branching event. When enough mutations reach fixation in a population to significantly differentiate from an ancestral population, a new species name may be assigned. A key point is that the entire population is different from the ancestral population so that the ancestral population can be considered extinct. It is easy to see from the preceding definition how controversy can arise among taxonomists when the differences are significant enough to warrant a new species classification. Anagenesis may also be referred to as phyletic evolution or gradual evolution. Cladogenesis is an evolutionary splitting event in which each branch and its smaller branches forms a "clade", an evolutionary mechanism and a process of adaptive evolution that leads to the development of a greater variety of sister organisms. This event usually occurs when a few organisms end up in new, often distant areas or when environmental changes cause several extinctions, opening up ecological niches for the survivors. A great example of cladogenesis today is the Hawaiian archipelago, to which stray organisms traveled across the ocean via ocean currents and winds. Most of the species on the islands are not found anywhere else on Earth due to evolutionary divergence. Cladogenesis is often contrasted with anagenesis, where gradual changes in an ancestral species lead to its eventual "replacement" by a novel form (i.e., there is no "splitting" of the phylogenetic tree).
Is it true that dogs have a missing link with their evolution evidence?
It does not matter.Biological evolution is about genetics, not repeat NOT fossils. It would have been known and understood if no fossils had ever been found, but it may have been later since fossils gave important clues.The notion of biological evolution has been founded on the obvious similarities among existing species as noted by Aristotle 2,350 or so years ago and by dozens of others since. I doubt that Aristotle knew much of fossils except as occasional curiosities.The fashion for collecting cabinets of curiosities among a leisured or moneyed class began with or before the Renaissance. Eventually the fossils became a field of study in their own right and even before Darwin was born the doctrine that all species that had ever existed, still existed had been shown to be false by fossils of extinct creatures. The doctrine of species remaining unchanged was probably false as well.As for missing links,“It has been asserted over and over again, by writers who believe in the immutability of species, that geology yields no linking forms. This assertion, as we shall see in the next chapter, is certainly erroneous. As Sir J. Lubbock has remarked, "Every species is a link between other allied forms." If we take a genus having a score of species, recent and extinct, and destroy four-fifths of them, no one doubts that the remainder will stand much more distinct from each other. If the extreme forms in the genus happen to have been thus destroyed, the genus itself will stand more distinct from other allied genera. What geological research has not revealed, is the former existence of infinitely numerous gradations, as fine as existing varieties, connecting together nearly all existing and extinct species. But this ought not to be expected; yet this has been repeatedly advanced as a most serious objection against my views.”Charles Darwin, 6th edition of On the Origin of Species , chapter X.The Origin of Species, Sixth Edition by Charles Darwin