5.5b Cladistics

20/05/2013 § Leave a comment

I can honestly say that I have never seen the word “cladistics” in this section of the textbook. This last blog (of the unit, of the semester, and of the year!) roughly outlines animal classification. Although there are similarities between plants and animals, they’re still different kingdoms with very different characteristics. Embryonic development is different between animals and plants, which is generally what separates them into different kingdoms.

While plants can be classified into just four different phyla, there are more than 30 phyla in the kingdom animalia. Some examples of animal phyla are: porifera, platyhelminths, mollusca (mollusks?!), cnidaria, annelida, and arthropoda (oh God, like insects, spiders, crabs and millipedes, ugh).

And to quickly discuss the classification of humans, on the hierarchy of taxa, we’d be in the order of Primates and the family Hominidae. This means that our closest relatives include the Gorilla gorilla (the gorilla, obviously), the Pan troglodytes (chimps!), and Pan paniscus (the bonobo, a very close relative of the chimp). I’m not sure how other people feel about this but it’s quite controversial as this classification suggests that humans, chimps and gorillas evolved from a common ancestor.

Well.

Looks like that’s it.

An entire year’s worth of blogging. I’ll be back in a few months for more biology. IT’S TEST-TAKING, LAB-WRITING, QUESTION-ASKING TIME.

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5.5a Classification

20/05/2013 § Leave a comment

This next blog is literally about naming species and how scientists group species. Another word for it is nomenclature; the naming of species. Biologists use the binomial system in order to give all species an international name for all biologists to use. They use keys in order to identify the individual and categorize them into their group. The main characteristics of the binomial system is that there are two words in the name: the first is capitalized and is the genus, the second is lower-case and is the species name. Handwritten, the binomial name is underlined, but when printed, they use italics.

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it’s not about the money (Chapter 18 Q & A)

16/05/2013 § Leave a comment

#3. 25 marks.

a) Analyze the methods by which the central bank might decrease the money supply. 

Money supply is the combined value of the currency and demand deposits of a country. The government has three methods in which it can change the money supply. They are to increase the discount rate, sell government bonds, and raise the reserve requirement ratio. Firstly, the discount rate is the rate charged by central banks when making loans to big commercial banks. If the discount rate is higher, big commercial banks will be given a signal that will discourage them from borrowing money from the central bank. This ends up raising the interest rates for borrowers and decreasing the money supply in the money market. Secondly, a government bond is a certificate issued by the government that can guarantee repayment of an initial amount charged with an agreed upon interest rate. When central banks sell government bonds into the open market, the reserves of of commercial banks will be taken out of private banks. The private banks will then charge more for what they have left, and because the bonds are sold with liquid money, the over supply in the money market will decrease. Selling bonds puts a downward pressure on price levels, output and employment, and it also increases interest rates, contracting consumption and investment as a result of reducing the money supply. Finally, raising the reserve requirement forces banks to reduce the amount they can loan out. The reserve ratio is the percentage of deposits that banks are required to hold at all times. Obviously if the required amount of money increases, there is less supply of money left in the money market.

 

b) Discuss the likely impact on an economy of a substantial decrease in the level of interest rates.

At first, a substantial decrease in the level of interest rates will give the economy beneficial consequences in the short term, but could possibly pose some difficulties in the long run. Interest rates are the opportunity cost of spending money, shown as an amount charged out of the initial amount of money provided. A substantial decrease with interest rates can only be accomplished through an expansionary monetary policy. This would involve decreasing the discount rates, buying government bonds, as well as lowering the reserve ratio. If at first the interest rates are what will fall, in the short run, investments will increase as a result. Firms and households see that the interest rates aren’t as high as they used to be and they don’t know when they’ll be low again so more often than not, investments will rise because firms and households are willing to spend more. This also means that growth and consumption may increase, and as a result, employment and inflation could increase in the long run. Since growth and consumption are part of the factors that make up the aggregate demand, or national output (GDP) of a nation [C + G + I + (X – M)], their increase could result in the rightward shift of the AD, which suggests economic growth for the nation. The shift could be great because the decrease in interest rates was substantial. That’s in the short run, but the long run could show a possible shift in the AS curve, which involves factors of production such as human capital (wages), and physical capital (technology). A shift in the supply is caused by the shift of the AD, as typically the supply tries to meet the demand. This means the people and the government can invest more on education, but a higher educated population could introduce lower wages to households and firms. There would be more competition because of a higher educated society – people would know how to use technology and fewer workers would be needed to do the job that previously forty workers were needed to accomplish. This would then put people into structural unemployment and they would need to learn new skills, perhaps go back to a school that would teach them more modern skills that could be of more use. Typically, a substantial decrease in the interest rate could increase investments but only assuming that the individuals in households and firms are confident enough to make those investments. If this is the case, like with countries like Japan, then investment won’t actually rise after the government decreases interest rates by a lot. In the end, it also really depends on the nation, its current conditions (if it’s experiencing steady growth or a recession) and the nation’s values.

5.3 Populations

15/05/2013 § Leave a comment

So we’re back to our regularly scheduled program, with only three blogs left, including this one. Jeez. This one will be a short blog about animal populations, how they change, and how they are graphically represented.

So our trusty study guide defines a population as a group of organisms of the same species, who live in the same area at the same time. Populations can change in four ways, which can be represented by the following math equation:

Population change = (natality + immigration) – (mortality + emigration)

Natality is defined as the [birth] production and addition of offspring into a population. Mortality is the exact opposite, wherein individuals die are lost from the population. Immigration, like with humans, is when individuals move in from somewhere else and join the population. Emigration is quite the opposite, where the individuals move away from the area to join a different population.

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5.4c Examples of Evolution

15/05/2013 § Leave a comment

Okay, let’s speed things up a little bit. What happens with evolution? A bunch of things, probably, but my puny mind can only handle so much. We can start off with Darwin’s finches, all of which he observed in the Galapagos Islands. The finches have since then been studied by Peter and Rosemary Grant, who catalogue the sizes of beaks and the size of the seeds (whether they’re large or small) every year. They discovered that with dry seasons, the collection of seeds would consist of mostly small seeds. Correlating with this condition, the next generation of finches normally have smaller beaks because natural selection had chosen those individuals in the generation with the dry season and small seeds with the smaller beak (which helped them survive). Similarly, seasons with large seeds generally produce a following generation of finches with large beaks that can crack the seeds easily. Variation in the shape and size of the beaks is therefore heritable and a result of the finches’ genes.

Alright, so, bacteria also evolve! Basically, humans use antibiotics to control bacterial diseases, right? Similarly with how the finches are picked off by natural selection, natural selection chooses the bacteria that are resistant to the antibiotics. Over time, the population of bacteria will consist more of those that are resistant to bacteria, because those reproduce while the non-resistant bacteria die off. See? Natural selection. Bacteria can evolve, too!

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5.4b Natural Selection

13/05/2013 § 1 Comment

I want to talk about natural selection. And the simplest way to do it is to describe its observations and deductions. For every observation, there is a deduction, or an explanation.

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5.4a Evidence of Evolution

09/05/2013 § Leave a comment

Let’s talk about evolution. Evolution in a biological context means the cumulative change in the heritable characteristics of a population. The idea that living organisms formed gradually from previous organisms was introduced by Charles Darwin, who proposed the concept of natural selection. Evidence for evolution by natural selection he presented were:

  • breeding of domesticated animals and crop plants
  • fossils
  • homologous structures
  • geographical distributions of animals and plants

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