THE SKUNK( Mephitis mephitis) - PowerPoint PPT Presentation

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THE SKUNK( Mephitis mephitis)

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  1. THE SKUNK(Mephitis mephitis) “The Origin of Species” section in Ch. 14 of Campbell Essential Biology With Physiology

  2. HOW THE SKUNK EVOLVED. • evolved from a common ancestors with weasels and polecats. Fossils tell us that skunks were alive in Germany about 11-12 million years ago. The creation of the species of the Striped Skunk occurred because of speciation which occurs in two different ways, allopatric speciation and sympatric speciation. Allopatric speciation is when two species are separated geographically and over time because of evolution they become different species (which applies to the Striped Skunk), while sympatric speciation is when two species live in the same area and a random change happens within one individual causing a new species to arise

  3. The theory of evolution, created by Charles Darwin, essentially is the idea that over time change of the inherited characteristics of different biological populations is what causes different species and animals to exist. This theory arose when Darwin visited the Galápagos Islands and each island had a different version of finches which all evolved to have different beaks to better suit their environment. This is an example of natural selection which is the basic idea that those best suited for their environment survive after small and gradual changes. An example of this is shown in skunks, where most species of skunk evolved in camouflaging different colors or markings, but the striped skunk instead of blending with its environment has evolved to stand out. The defined black and white stripes on the Striped Skunk are used to warn predators from the skunks strong musk which can be sprayed. 

  4. Reproductive barriers for the skunk species. Prezygotic barriers include: Temporal isolation Habitat isolation Behavioral isolation Mechanical isolation Gameticisolation. This specifically shows temporal isolation:

  5. Mechanism of speciation • Speciation is the process by which one species splits into two or more species • Speciation occurs either as; • Allopatric speciation, due to geographic isolation • Sympatric speciation, without geographic isolation

  6. Speciation of the skunk Allopatric speciation is when two species are separated geographically and over time because of evolution they become different species (which applies to the Striped Skunk) sympatric speciation is when two species live in the same area and a random change happens within one individual causing a new species to arise. But this only occur in plants

  7. evidence showing speciation of the skunk • Natural selection which is the basic idea that those best suited for their environment survive after small and gradual changes. An example of this is shown in skunks, where most species of skunk evolved in camouflaging different colors or markings, but the striped skunk instead of blending with its environment has evolved to stand out. The defined black and white stripes on the Striped Skunk are used to warn predators from the skunks strong musk which can be sprayed. 

  8. Role played by natural selection to the skunk. • Natural selection is the gradual process by which biological traits become either more or less common in a population as a function of the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. It is a key mechanism of evolution. The term "natural selection" was popularized by Charles Darwin who intended it to be compared with artificial selection, which is now called selective breeding.

  9. Skunks have many natural predators. The young and weak also can be removed from the population by disease and however, as result of Natural Selection.  it's ability to produce viable offspring's id what makes the species to survive. If skunks were spontaneous ovulators, they would risk not producing young ones during their one breeding season. The animals that had induced ovulation were able to put more young (i.e., more genes) into the next generation. The different species have undergone gradual changes to allow for environmental survive and accord them with advantageous characteristics to help not making the species extinct.

  10. References • Gracie, C. (2012). Spring wildflowers of the Northeast : a natural history. Princeton: Princeton University Pres • Jenkins, D. (2001). Lockheed secret projects : inside the Skunk Works. St. Paul, MN: MBI Pub. Co • Berta, A. (1988). Quaternary evolution and biogeography of the large South American Canidae (Mammalia, Carnivora. Berkeley: University of California Press • Werner, C. & Werner, D. (2007). Evolution: the grand experiment : the quest for an answer. Green Forest, Ark: New Leaf Press • Aronstein, D. & Piccirillo, A. (1997). Have Blue and the F-117A : evolution of the "Stealth Fighter. Reston, Va: American Institute of Aeronautics and Astronautics