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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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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5.2b Greenhouse Effect

06/05/2013 § Leave a comment

Today we’re just going to keep talking about global warming as a continuation of the greenhouse effect topic. Global warming has had an impact on many of earth’s habitats, or the environment in which a species normally lives or the location of a living organism. I guess we could say it’s technically just where an animal lives.

There are numerous consequences of global warming, and a lot of them affect the environment where many animals live. Glaciers, for example, obviously melt with the increased temperature, which will greatly reduce the size of the Arctic. It’s expected that the ice caps will disappear completely at this rate. Other than the disappearing polar ice caps, polar bears and other animals who live on the ice will most definitely lose their habitat and die off. The ice-turned-water will cause sea levels to rise, as well as some flooding if there’s enough melted ice. The change in temperature of the water could also do something to affect the marine animals living in the oceans. The movement of animals in response to the melting ice could also trigger a shift in the food chain they’d been previously living and would alter almost the entire ecosystem. Also, the melting of permafrost during the summer would increase the rates of decomposition of trapped organic matter, which in turn means the release of carbon dioxide, adding into the atmosphere.

The precautionary principle is a way the government and leaders of a nation (?) handle claims and theories that have to do with any potential scientific threats. Rather then what would normally happen (prove that something is guilty of doing … something), scientists are instructed to prove that something won’t do harm before following through. For example, when people became more aware of the possibility that the production of CO2 was causing global warming, the people who needed to continue CO2 production had to follow the precautionary principle to prove that more CO2 production (or whatever action they needed to take) wouldn’t cause harm.

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