Domestication and Development of Breeds

How have these animals adapted to various special environmental or genetic influences?

What is a species? 1. A species is a population of organisms that have a common Latin name. a)Members of this group are very closely related; together with the genus name it forms the scientific name

What is a species? 2. A population of organisms, other than bacteria, that can be interbred naturally to produce fertile offspring a)The genetic makeup of the two species is so different that offspring are either not created, die shortly after birth or are sterile b)There are exceptions, wolves (Canus lupus) can successfully produce fertile offspring when bred with a domestic dog (Canus domesticus), however tigers (Pontera tigris) and lions (Pantera leo) can produce ligers or tiglons but are sterile

What is a species? 3. The two species can also be separated by time a)It may be possible that domesticated horses and prehistoric horses could have mated, but since they don’t exist in the same time period they are considered different species

What is a species? 4. Environment and space may be a factor a)Animals that live in a forest and those living in the plains will never meet and are considered a different species. Ex: Dingos and domesticated dogs can successfully reproduce, but since dingos don’t associate with humans and dogs are dependent on us they remain separate populations

What is a species? 5. Social structure and behavior also presents animals of different species from coming into contact and reproducing in the wild

How is a species formed? 1. New species are created by splitting an existing species population into two or more separate groups. 1.These groups must be prevented from interbreeding either by disturbance, natural barriers, time or some other “genetic wall” a)After being separated, the two groups must be subjected to at least slightly different environments b)Given enough time these different environments will force divergent selection to occur to the point where the groups will become independent and mutually exclusive species

How do humans effect genetic changes? 1. Selection can either be natural or motivated a)Natural selection i.When the environment changes for an unrelated reason. This change brings about genetic change. ii.Occurs because it is the path of least resistance b)Motivated selection a)When specific individuals in a population are purposefully prevented from breeding and others are encouraged to breed based on the traits that are desirable b)Requires a desire to change the nature of the gene pool c)Human beings

How is a species formed? New species are created by splitting an existing species population into two or more separated groups. New species are created by splitting an existing species population into two or more separated groups. –Interbreeding prevented by:  Disturbance  Natural barriers  Time  “Genetic wall” –Subjected to different environments –Given time until the point when groups are independent and mutually exclusive

What effect do humans have on evolution, selection, and the genetic modification of animals?

Human Effect Selection can either be natural or motivated Selection can either be natural or motivated –Natural selection  When the environment changes for an unrelated reason. Change brings about genetic change.  Occurs because it is the path of least resistance.

Human Effect –Motivated selection  When specific individuals in a population are purposefully prevented from breeding and others are encouraged to breed based on the traits that are desirable  Requires a desire to change the nature of the gene pool

Human Effect –Humans involved in both types  Pesticide use is not intended to change the genetics of the insects. However, insects most affected are killed first and the resistant insects are left to breed.  Most obvious type of motivated selection is the process of domestication

Human Effect Domestication-process by which humans have created an interdependence with certain animal species. Domestication-process by which humans have created an interdependence with certain animal species. –Performed in four steps: 1.Develop a loose contact with animals Humans and dogs share common habitats, habits, behaviors, food sources and territoriesHumans and dogs share common habitats, habits, behaviors, food sources and territories 2.Confine animals to our environment 3.Motivated selection is used to alter the genetic make-up population 4.Remaining wild population is systematically exterminated to separate the domesticated from wild and increase human dependence

Human Effect Domesticated Animals need to be: Domesticated Animals need to be: –Hardy –Not afraid of humans –Comfort loving –Useful to humans –Able to breed in captivity –Socially oriented