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Rat Species on Island C
Transcript of Rat Species on Island C
If our rat was washed away by the tide and landed on another island:
a) The rat would not have a good chance of survival if it landed on any other island because its adaptations are only suited for the environmental conditions of its own island. If it went to any other island, the other rats would be more adapted and so the rat would have a much lower chance of survival compared to them.
b) The rat’s alleles would not be able to be added to the gene pool on all of the islands because the rat has become a different species after evolving and adapting to the environmental conditions on its own island. Hence it would not be possible for it to breed with the rats on the other islands.
The island is somewhat dessert-like. It is almost completely barren and the only vegetation on the island is a few species of cacti. A species of very large birds nests on the annually. They build their nests on the rocks on the west side on the island, which is cooled by the cool shore wind. They also protect their eggs from the sun by standing over of the eggs with their wing outstretched.
Rats on Island C
500,000 years ago, a pair of rats were washed off to the Island from the coast of South America. Their offspring now thrives on the Island.
In Real Life...
Allopatric speciation is a specification in which a population is split into two or more groups by geographical barrier. Allopatric speciation is also called geographical speciation (McGraw-Hill Biology 11).
Adaptive Radiation, a form of allopatric speciation, is the diversification of a common ancestral species into a variety of differently adapted species. How adaptive radiation works is the offspring from a specific parent disperses to different areas of the world, giving the offspring the opportunity to change in response to the new environment. It occurs a lot with islands, but also happens in areas where the environment changes (McGraw-Hill Biology 11, 2010).
Pre-zygotic barriers are barriers that occurs before the formation of a zygote can take place. There are five different types of pre-zygotic barriers which are behavioral isolation, habitat/ecological isolation, temporal isolation, mechanical isolation, and gamete isolation. These barriers either prevent mating and/or fertilization (McGraw Hill Biology 11, 2010).
Post-zygotic barriers are barriers that occur after the formation of a zygote occur. There are 3 different types of post-zygotic barriers which are zygotic mortality, hybrid inviability, and hybrid infertility. These barriers occurs after mating and it prevents hybrid zygotes from developing (McGraw-Hill Biology 11, 2010).
Reproductive barriers are mechanisms that impede two species from producing fertile or viable offspring. There are two main types of reproductive barriers, they are pre-zygotic barriers and post-zygotic barriers (McGraw-Hill Biology 11, 2010).
Reproductive barriers are important to speciation because the barriers help separate populations into which will eventually turn into two different species. These two species form because one of the population may encounter a different environment and have to adapt and change to survive. These changes could make it hard or impossible to reproduce with organisms with the original population, thus creating a new species (McGraw-Hill Biology 11, 2010).
• Brown, grey or black fur (unless albino) that covers them, except ears, tail, and feet
• Hearing is very good
• Eyes are suited for the dark
• 16 teeth, incisors are always growing from base (rats gnaw on tings to keep them to a manageable length, if not then they will curl back into mouth or in front of nose
• Powerful jaw muscles (12 tons per square inch)
• Carry diseases in saliva, fur, and external parasites
(Net Industries, n.d.)
• Will bite or attack if it feels threatened
• Rats practically eat everything
• Scale brink walls
(Net Industries, n.d.)
• Rats do not sweat, they regulate there temps by constricting or expanding blood vessels in their tails.
(Lentini & Mouzon, 2006)
They can swim really well (tread water for 3 days, survive being flushed down the toilet)
Can fall as far as 50 ft and land uninjured.
Fit through a hole the size of a quarter
-Long, sharp teeth to bite into cacti and attack tortoises
-Small front feet and long nails to dig underground burrows to stay in during the day.
-Light brown fur to blend in with the environment to avoid being eaten by the birds
-Thick, insulating fur to keep them warm from sea breezes
-Active at night, so they can attack the eggs of the birds as the birds only protect their eggs from the sun during the day.
-Dig underground burrows to keep themselves cool during the day and avoid predation
-Efficient kidneys, producing urine that is highly concentrated so they keep most of their water inside their body. This allows them to survive on the barren island where water is only found in the cacti.
-Oily fur to prevent sweating so they preserve water inside their bodies.
An example of how natural selection was at work was the distinct color change of the rats. The pair of rats that colonized the island were both dark brown, almost black furred. Over time, there was a genetic mutation that caused a color change to a light brown, beigeish color. That rat survived predation over his dark brown furred family. This rat then reproduced more light furred rats, who almost always survived predation better than the dark furred ones. After a large period of time, almost all of the dark furred rat were eaten and the population was composed largely of light brown, beigeish color.
Our rat has eight adaptions.
Albert, S. (n.d.). Structural Adaptations of the Kangaroo Rat. Retrieved April 6
2014 from: http://animals.pawnation.com/structural-adaptations-kangaroo-rat-3773.html.
BirdLife International (2014). Blue Chaffinch (Fringilla teydea) - BirdLife species
factsheet. Retrieved April 6, 2014, from http://www.birdlife.org/datazone/speciesfactsheet.php?id=8756
Dunlop, J., Francis, L., Gasper, P., Gibbons, K., Grace, E., Mills, A., & Searle, S.
Toronto: McGraw-Hill Ryerson.
European Commission (2014, March 3). Chaffinch (Hierro subspecies) - Fringilla
Coelebs Ombriosa. Retrieved April 6, 2014, from ec.europa.eu/environment/nature/conservation/wildbirds/threatened/f/fringilla_coelebs_ombriosa_en.htm
Lentini, L., & Mouzon, D. (2006, December).
20 Things You Didn't Know About...
Rats | DiscoverMag-azine.com.
Retrieved April 5, 2014, from http://discovermagazine.com/2006/dec/20-things-rats.
Madeira Birdwatching (2014). Madeiran Chaffinch (Fringilla coelebs
maderensis). Retrieved April 6, 2014, from http://www.madeirabirds.com/madeiran-chaffinch-fringilla-coelebs-maderensis
Net Industries (n.d.).
Rats - Physical Characteristics, Behavior, Reproduction, Diet,
Species, Rats And Humans - Mice, Genera, World, and Major - JRank Articles.
Retrieved April 5, 2014, from http://science.jrank.org/pages/5751/Rats.html.
Science.jrank.org. (n.d.). Rats - Physical Characteristics. Retrieved April 6 2014
Spencer, C. (2012, August 6). The Traveling Geologist: The Canary Islands -
Tenerife. Retrieved April 6, 2014, from http://www.travelinggeologist.com/2012/08/tenerife-part-1.html
Wikipedia (2014, February 14). Blue Chaffinch. Retrieved April 6, 2014, from
Wikipedia (2014, March 19). Common Chaffinch - Wikipedia, the free
encyclopedia. Retrieved April 6, 2014, from http://en.wikipedia.org/wiki/Common_Chaffinch
The F. teydea, known as the Blue Chaffinch, is only found on Tenerife. The Blue chaffinch is a relatively blue and grey finch. It has a blue-grey head and back. The underparts have a pale pink color near the chin and throat, but then become blue-grey as it moves down the body. It has the same white wing-bars and white on their tails as the common chaffinch (BirdLife International, 2014).
The F. c. moreletti is very similar to the F. c. maderensis, but moreletti is a smaller bird. It is skinner than the maderensis, but shares all the other traits. The pale orange neck and chest that fade, the yellow bar on the back, the white wing-bars, and the white on their tails.
The F. c. ombriosa is small, has an orange-pink neck and underpart that fades into a pale pink/cream color. Its crown and upper back are grey with a hint of blue. The lower back has a hit of pale orange-pink that keeps going into the tail. It has the white wing-bars and shoulders, as well as white in the tail (European Commission, 2014).
Lastly the F. c. palmae has an orange underpart, a dark grey-blue crown, and the back is a lighter shade of grey-blue with a little bit of brown in the bottom of the wings. This bird white wing-bars, white in the tail and the white shoulders.
The F. c. maderensis is a medium size finch that has a pale orange neck and chest that fades into a creamy pink. They have the same white wing-bars as the other finches, but there is a yellow bar across the upper back (Madeira Birdwatching, 2014).
The Canary Islands are a chain of seven volcanic islands located in the Atlantic Ocean. The islands are El Hierro, La Palma, La Gomera, Tenerife, Gran Canaria, Fuerteventura, and Lanzarote (Spencer, 2012). There are many different species of animals that live on these islands and one of them is the chaffinch. The common chaffinch is a small bird from the finch family. It has rust-red underparts, grey-blule crown, and brown or beige feet. The males are more vibrant in color than the females, but both genders have white wing-bars and white on their tails. The type of beak they have is small, sharp, and pointed. In the Canary Islands there are five subspecies of the chaffinch, F. teydea, F. c. maderensis, F. c. moreletti, F. c. ombriosa, and F. c. palmae that live on five out of the seven islands. All of these finches are very similar to each other except for their colors.
Overall the various subspecies of the chaffinches are very similar other than their specific colors. There are no other obvious variations between them. There could be tiny variations on the birds on their specific islands due to human interference, but the environment of the Canary Islands is similar to each other and they likely experience most of the same environment and climate issues.