Darwin's 4 Postulates
Veronica Quintana
Variation
There is a lot of variety within every species, which makes earth very rich having different types of animals in every corner of the world. Since every type of animal is not the same, that is why our world has different kinds of environment to be able to sustain each species and offering them what they truly need to live and survive. (Each species is suited in an environment that they 'like' the most.) Variation also includes; for example: Different color of insects (butterfly wings), alimentation is different for each species, abilities are different (flying, jumping, swimming), size, eye color, etc. Everything has its own variation.
Inheritance
The offspring of each species may look like their parent because the offsprings inherit special traits from both of their parents. For example; if a big black rabbit has intercourse with a white small rabbit, one of their offsprings may be black, but small while the other offspring may be white and big. Not all offsprings from the same parent inherit the same traits, the probabilities are very different. Another example is; if both parents are tall, the offspring will most probably be tall too.
Differential Survivor
This process os known as Natural Selection, some external conditions may affect survival for some species. This are non-genetic changes that occur in species, things that cannot be passed down to the next generation. Some organisms do survive long enough to produce offsprings, while others don't. The one's that do get to produce an offspring may produce more than others.
Extinction
Some traits in some species are not able to live nor survive in the environment that they are put into so they die. Extinction is the end of an organisms 'line'/ end of an entire race, extinction is definite when the last organism of a specific type of animal is dead. In the graph below you can see the animal extinctions through the years 1500 to present day, sadly extinction have increased enormously since 1900.
Sources:
B. (2014). Discontinuous and Continuous Variation. Retrieved April 4, 2016, from http://www.bbc.co.uk/bitesize/standard/biology/inheritance/variation/revision/4/
Freeman, S., Black, M., Taylor, E., Monroe, J., Allison, L., Podgorski, G., & Quillin, K. (2002). Biological science. Upper Saddle River, NJ: Prentice Hall.
- Neuhauser, A. (2015, June 19). 75 Percent of Animal Species to be Wiped Out in ‘Sixth Mass Extinction’. Retrieved April 4, 2016, from http://www.usnews.com/news/blogs/data-mine/2015/06/19/75-percent-of-animal-species-to-be-wiped-out-in-sixth-mass-extinction
P. (2014). Genetics. Retrieved April 05, 2016, from http://biology.tutorvista.com/cell/genetics.html