5.6 [ Speciation, Rate of Evolution, Macroevolution ]

     Natural selection leaves the strongest to survive, so the species with the favorable trait survives with the unfavorable trait dies. With only the desired traits to survive in the environment survive, some believe this is classified as a new species. This process is called speciation which is the formation of a new species, this is carried out by allopatric speciation which happens in three steps.

1) A physical barrier separates the species into two or more groups isolated from one another. A physical barrier is some change in the environment, an example would be a construction site on a river sperating the two sides.

2) Natural selection influences the environments in different ways because of the separation between the two or more and because of this species evolve in different ways.

3) Eventually, the two environments would have separated so much that the species that were split because of the physical barrier can no longer breed and have become separate species.

5.5 [ Mutations, Sexual Reporduction ]

5.4 [ Theorys of Evolution, Natural Selection ]

     In the 1800's the first theory of evolution was thought up by Jean-Baptiste Lamarck. He came up with a theory called spontaneous generation where species were continually being created from non living matter. Lamarck's theory on evolution was the traits of the parents that they gradually over time gained would be transfer to there offspring. For example if a adult dalmation had all black spots and and is tall and muscular from stretching and running a lot. Then its offspring would be tall muscular and have black spots. However this theory also has many flaws such as missing limbs scars or any other disfiguration were not passed onto the offspring. Lamarckism or inheritance of acquired characteristics was immediately discredited. 

 

     The next theory of evolution was proposed by Charles Darwin in 1858. On his voyage to the Galapagos islands he studied birds. Most notably a bird called a finch, he noticed different variations between the finches. For example a long skinny beak was meant for getting bugs out of trees, bigger wider beaks were made for crushing its food. Although for Darwin's theory to work four things must be present in the environment. Overpopulation, variation, competition and survival of the fittest. Once all the criteria are meet the species will start to adapt to there new environment by mutation in order to survive.

http://www.biology-online.org/2/11_natural_selection.htm

http://ts3.mm.bing.net/images/thumbnail.aspx

http://en.wikipedia.org/wiki/Darwin%27s_finches

Ritter, B., Burley, K., & Fraser, D. (2007). Chapter 5 Evolution. Nelson. (Original work published 2007)

5.3 [ Homologous structures, Embryology, Vestigial Features, Biochemistry ]

     Features with similar structures but different functions are called homologous features. A bat’s wing and a whale’s flipper are homologous features because they have similar bone structures. But one is mainly for flying through the air while the other is to swim through water. Structures which are similar in appearance and function, although have different evolutionary attributes are named analogous features.  The wings of a fly, a moth or a seagull are analogous because they have all developed the same function and slight appearance but developed differently depending on the animal’s surroundings,  they all have one common function which is flight. With the power of technology moving at a ever consistent rate, scientists can pick traits they want. This is called artificial selection,a desired trait such as two dogs that are tall- are bred together and the next generation of dogs will be even bigger and taller. If artificial selection is continued, the population will be taller.
 

     Vestigial features are basically the useless structure that serves no function. Although at one point it may have served a purpose. Like in the wings of ostriches,emus and other flightless birds.They are remnants of their flying ancestors' wings, useless in there current state they have not been eliminated because nature works very slowly. Although they do nothing and serve no purpose they still are there. In embryonic development  evolutionary similarity  among species if evident. Similar features in development appear, human embryos posses a tail like feature similar to those of chickens or fish. The tail serves no function but later forms the first stages of the tailbone. Another way to determine if two species are related is to look at ammino acids. Amino acids are a chemicals that contains nitrogen which can form proteins. For example a ostrich will have different ammino acids from a red panda. 

      Another adorable animal that has vestigial features is the kiwi... bird. Its a bird with feet and a long beak. Its vestigial features are its former wings, it no longer has arms. Although it still has the bones that its ancestors had which means at one point in its evolution it had wings.


Ritter, B., Burley, K., & Fraser, D. (2007). Chapter 5 Evolution: Evidence of Evolution from Biology, Biology (p. 144-149). Nelson. (Original work published 2007)

http://www.photochart.com/photo_2457_Bad%20Hair%20Day.html N.p., n.d. Web. 28 Apr.2011

http://fc06.deviantart.net/fs39/i/2010/119/2/4/Kiwi_by_Alejandra_perez.jpg

5.2 [ Paleontology, Radiometric Dating , Biogeography ]

     The earth is an ever changing ecosystem only the strongest species will survive. Before there was different land masses there use to be a combined land mass called Pangaea. Most evidence suggests that all modern species evolved from the ancestral species. We assume this from careful examination of fossils which is called Paleontology which is the study of fossils.  Fossils are made by minerals in water that seep through layers and layers of soil and into the bones of a animal that was burried and then replace the living tissue. Through radiometric dating and biogeography we can determine that many different species have lived on Earth, very few of today's species were even alive one million years ago. To put that into context the earth is about 4.5 billion years old. And almost all of those species are now extinct. At first the progression of species went from very basic single celled organisms to more complex multi-cellular organisms. Notably most living species in areas have similarities with fossisls found in the area suggesting that evolution took place.

      In 1903 radioactivity was discovered it was a source of heat energy. Radioactive decay also provides a form of a clock, giving scientists a mean to determine the age of the Earth. Radioactive decay changes a atom into an isotope of the same or different element. For example uranium 238 decays into lead 206  we call these decay rates called half-lives.The isotopes are not affected by temperature, moisture or any other environment conditions. With consistent half lives isotopes can be extraordinarily precise radiometric clocks. A technique used to determine the age of a rock or fossil is called radiometric dating. Biogeography is defined as the study of the geographic distribution of life on Earth, with biogeography we find clues to the history of life on Earth.Over 225 million years Earths landmasses have changed. The Earths tectonic plates eventually separated the landmasses we see today.So for example you may find dinosour remains in south america and also find the same type in Africa which suggets at one point the two continents were connected.


Ritter, B., Burley, K., & Fraser, D. (2007). Chapter 5 Evolution: Evidence of a Changing Earth., Biology (p. 140-143). Nelson. (Original work published 2007)

Roar. N.d. http://free-extras.com/images/roar-1750.htm. N.p., n.d. Web. 22 Apr.2011.

5.1 [ Taxonomy, Binomial Nomenclature ]

     There have been well over two million different animal and plant species that have inhabited the earth. So having a system called taxonomy to help categorize and sort them all is very handy. Taxonomy is defined from dictionary.com as the science dealing with the description, identification, naming and classification of organisms. Our current biological system of classification was created by Carl Linnaeus. His system was focused mainly on an organisms physical and structural features, he created rules for naming plants and animals called binomial nomenclature. Binomial nomenclature is defined as a method of naming organisms by using two names, the genus name and the species name. An example of taxonomy would be the red panda so then its binomial name would be Ailurus fulgens.

Kingdom : Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Ailuridae
Genus: Ailurus
Species: Fulgens

       Taxonomy starts from a very big category and slowly gets smaller so we may identify an animals relatives and general family until we get to the exact species. For example you may think a red panda and a giant panda are of the same family but they are actually farther apart then that. The giant pandas kingdom is Amimalia, its Phylum is Chordata, its class is Mammalia and its Order is Carnivora. Those are where the red panda and the giant panda are related. The giant pandas family is Ursidae, its Genus is Ailuropoda and its species is Melanoleuca. They are related but are far distant cousins of each other.

 

Biology 20-30. N.p.: Nelson, n.d. Print.

"Taxonomy." Taxonomy. Dictionary.com. Web. 21 Apr. 2011.      http://dictionary.reference.com/browse/Taxonomy.

   Glatston, Angela. "Red Panda." Wikipedia. http://en.wikipedia.org/wiki/Red_panda, Web. 21 Apr. 2011.    http://en.wikipedia.org/wiki/Red_panda."Giant Panda." Wikipedia. http://en.wikipedia.org/wiki/

     Giant_panda, 19 Apr. 2011. Web. 21 Apr. 2011. <http://en.wikipedia.org/
     wiki/Giant_panda>.