Canis familiaris Dogs Canis familiaris Dogs This series of slides illustrates :Variation in dogs. The genetic similarity of dogs - they are all descended from the same ancestor. Genetic and environmental variation. How new varieties are formed by artificial selection. Artificial selection in other domesticated animals.

Dogs have a lot of variation The same species? You must be joking The same species? You must be joking If you were an alien zoologist, coming to Earth for the first time, would you think that these animals are all the same species? Dogs have a lot of variation Rather than saying - “dogs vary a lot” because the word variation is used in the biological sense here. If you were an alien zoologist, coming to Earth for the first time, would you think that these animals were all the same species? You may need to discuss what species means. What does species mean?: the same kind of organism (or animal), the important point is that they can all reproduce together. All dogs are the same species because any two kinds of dog (even great-dane and chihuahua…) can produce fertile offspring. The same species? You must be joking! Why are dogs so different from each other? Bring out the idea that dogs have been “made” by humans to do different jobs. They are domesticated animals.

Woof! Dogs come in all shapes and sizes. But they all came from the same ancestor. Woof! Woof! Dogs come in all shapes and sizes. But they all come from the same ancestor. What could that ancestor be? What wild animal looks like a dog?

Great...Grandma Canis lupus The wolf Canis lupus Great Grandma DNA studies indicate that all dogs came from wolves, it is possible to interbreed dogs and wolves but the offspring (wolf-dogs) are very difficult to train and can be very dangerous. Remains of dogs have been found in human settlements for thousands of years, they have probably been domesticated for at least 5000 years, maybe a good deal longer, maybe from the very beginnings of Homo sapiens when they first encountered wolves. Dogs and humans have a very close relationship, many dogs are treated as humans (how many dogs are given birthday presents?).

What are the Look at differences the eye shape, between dogs the ears and noses What are the differences between dogs and wolves? What are the differences between dogs and wolves? What is the same? Look at the eye shape, the ears and noses. Eye: Wolves have olive shaped eyes, dogs round. Ears: Typically wolf ears point up, and dogs tend to flop down. Noses: the same, black, moist and bare. Similar snout in most dogs. Also discuss fur colour, whiskers, behaviour, barking and howling (dogs) howling (wolves) etc What is the same?

Look at the tail and the paw prints Wolves have longer teeth too. Look at the tail and paw prints. Wolves have longer teeth too. Tail: Typically dogs tails point up and wolves down. Paw prints: Wolf prints are larger and oval shaped, the toes and claws are more parallel. Dog prints are smaller, round and the toes and claws point outwards. Wolves also have a narrower chest than dogs. Wolves have longer teeth too.

Hard to believe we both came from wolves

We breed dogs to do different jobs What do these dogs do? We breed dogs to do different jobs. What do these dogs do? What makes them good at their jobs? Doberman: Guard dog, police dog. Fierce, can be trained, dangerous, big… Collie: Sheepdog Obedient, intelligent, can live outside in cold weather, doesn’t harm sheep. Blood hound: Hunting by scent. Incredible sense of smell, strong for when animal is found, will keep animal in position until hunter arrives. St. Bernard: Finding people lost in the snow or under an avalanche. Big and strong to get through snow, thick fur for protection against cold, good sense of smell to find people under snow, intelligent. Miniature dachshund House pet, guard dog to warn of intruders. Small, cute, cuddly, not too bad tempered, loud bark. Dachshunds were originally bred to go down badger holes! What makes them good at their jobs?

What did the poodle inherit from its parents? Take a poodle and change it! Take a poodle and change it! What did the poodle inherit from its parents? What environmental changes have occurred? Introducing the differences between inherited and environmental changes. As well as the obvious changes in fur you could also discuss behavioural changes. Dogs inherit particular behaviour patterns - how they react to other dogs, staying with a group (or owner/family), being territorial. But they can also be trained to do things such as sitting, staying, being house trained etc - these are environmental changes. What did the poodle inherit from its parents? What environmental changes have occurred?

How can I do it? How do we make different kinds of dogs? I want to make a new kind of dog It must be a good swimmer And have an incredible sense of smell What could this dog be used for? How can I do it? How do we make different kinds of dogs? I want to make a new kind of dog It must be a good swimmer And have an incredible sense of smell What could this dog be used for? This slide is to make the students think about how man-made dogs are and to think about how it is done. Varieties of dogs (Doberman, Chihuahua, Sheepdog etc) are purely human distinctions, dogs have always been selected for particular characteristics. This is called artificial selection. (Note: wolves have been selected for the characteristics needed to live in their environment by natural selection, they are well adapted to their way of life.) These changes will need to be inherited so you must breed from dogs that already show the characteristics that you require and select the best offspring from each generation. So here you would breed big footed, streamlined dogs with dogs with a good sense of smell. Students could make up their own dogs.

Many other animals have been changed by humans Do you think this cow could live in wild Africa? What do you think wild cows were like? Can you think of other examples? This slide is included to widen the discussion on artificial selection. This cow is not adapted to living in Africa, it must be milked regularly, the huge amounts of milk are very “unnatural”. An animal like this could not run from predators nor defend itself. Perhaps the Spanish bulls used in bullfighting could be mentioned, they are quite wild and very aggressive. Wild cows were probably the Aurochs, and they could be compared to the present day African Buffalo: Very powerful, dangerous horns, form herds for mutual protection. Other examples of domesticated animals which can be compared to wild relatives are: sheep, goats, cats, pigs… Crop plants could be mentioned here too: Wheat (from wild grasses), Brassicas (cabbage, cauliflower, broccoli are all descended from the same wild cabbage), apples (crab apples) etc Do you think this cow could live in wild Africa? What do you think wild cows were like? Can you think of some other examples?