Invasive species

There are at least 358 species known to be invasive or alien species in South America. Brought by natural causes, accidents or human influence, they present a great threat for the South American native species and the ecosystems. It is therefore extremely hard to indicate some invasive species as being the most harmful ones. Based on five qualitative determinants, these may be considered the WORST INVASIVE SPECIES: 

Qualities:

• Ability to adapt easily
• High rate of reproduction
• Significant disruption of an ecosystem
• Capable of reducing the number of another species or replacing it
• Distribution and demographics in South America 

1. Aedes albopictus (Asian tiger mosquito), known best in Brazil as "mosquito da dengue": original to Northern Africa, transmits deadly diseases such a malaria and dengue.
2. Carcinus maenas (European green Crab): has significant impacts on epibenthic and infaunal species, such as bivalves, other mollusks, and crustaceans, through predation, competition, and burrowing activities
3. Cervus elaphus (European red deer): competes with the endangered species of deer for food, prevents regeneration of favored plant species 
4. Anoplolepis gracilipes (yellow crazy ant): devastates species, causing a rapid alteration of the ecosystem.
5. Acacia longifolia (tree): some impacts include reduction in native biodiversity, ecosystem change, changes in habitat and in hydrology and fire regimes 

One Meat-free Day a Week, Keeps Global Warming Away

The United Nations proposed the reduction of meat consumption in the world to curb global warming. Many are unaware that raising animals can contribute to the rate of global warming and are incapable of understanding how harmless animals, such as cows, can drastically affect the world's climate. Others, may see this proposal as something absurd for they do not wish to give up on eating meat, as something essential for their diet. What is misunderstood, is that we as current inhabitants of this planet have to decrease greenhouse gas emission, if one cannot change his or her eating habits, one has no idea of how much harder it would be to change or even reduce their means of transport. Therefore, as the simplest and most effective solution, there should be a significant reduction on the meat production and consumption in the world.
Meat production, often forgotten, is one of the greatest contributors to the emission of greenhouse gases. It is responsible for approximately one fifth of the greenhouse gas emissions and methane, a gas emitted as animal waste, is over twenty times more harmful than carbon dioxide.  Studies show that one kilogram of beef is equivalent to the release of 36.4 kilos of carbon dioxide. Based on this data, it is undeniable that a reduction on meat production would also cause a reduction on the rapid rate of global warming.
Despite the urgency in finding solutions to decrease the global warming rate, scientists and officials must understand that humans need a time for adaptation and acceptation of a new idea. The Compassion in World Farming, asked the governments to create a campaign to reduce meat consumption by 60 per cent by 2020. In less than nine years, such an accomplishment is unrealistic. On the other hand, the government should be active in informing and educating the people about how such a simple act would not only ameliorate their lives, but also the world's.
There are several negative consequences due to this policy though. For instance, if there were to be a reduction, that would mean that certain farmer would suffer affecting unemployment and the economies of countries. Around 56% of the meat is produced in developing countries such as China and Brazil. A drastic reduction would severely damage these economies and would generate great dissatisfaction. Therefore, the government should interfere by providing such farmers with subsidies and encouragement to reduce. Another problem is the cultural and traditional impacts. In some cultures, eating meat is very valued and a strong part of people's lives. The Brazilian population, for example, eats meat everyday and usually appreciates a "churrasco". In a churrasco, each person eats the equivalent o a one week consumption of meat. Demanding a reduction would not be easily accepted by the consumers or the restaurant owners.
When comparing the possibilities for curbing global warming, there is not one solution that will be able to plead everyone in the world, after all, reaching unanimity with a population of 6 billion people is not possible. It is essential that people are willing to compromise and fight against global warming, which is not affecting our generation, but will definitely have impacts on the next. How hard is it to keep from eating meat for one day, and eating a delicious salad. For those who absolutely despise leaves, imagine how much harder it would be for them to have to keep their cars at home for one day. Although it might sound absurd at first, having a "meat-free" day a week would indeed reduce a great release of greenhouse gas emission, decreasing the rate of global warming, preserving our planet for at least a greater period of time.

Indian Embassy "Backyard"

According to the Simpson's diversity index, the Indian Embassy backyard is very diverse. The diversity, represented by D, ranges from 0-1, where 1 represents no diversity and 0 infinite diversity. After calculating the number of different plants by meter by combining the data with the ones of other groups, D turned out to be .095. This number is nearly zero, showing the area is very diverse. This is not surprising since the vegetation in the Indian Embassy backyard is the cerrado, which is considered to be a very diverse ecosystem. Since the Simpson's diversity index uses an inverse thinking, many choose to use the Simpson's index of diversity which is (1-D). Despite having the same result, it looks more logical since as the index of diversity approaches 1, the area is more diverse. In this case, 1-D is 0.905.

Plant Measurements

1. Height: approximately 9 m
2. DBH: approximately 40 cm
3. Crown: 9.30 m
4. Leaf Light Absorption:
1. Dark green: 99%
2. Light green: 94%
5. PH of soil
1. Near tree: 6.6
2. Far from tree: 6
6. Temperature of soil
1. 0 m: 20.5 degree Celsius
2. 3 m: 21 degree Celcius

Shark Dichotomous Key

There are FOURTEEN different families of sharks. Some of them look so similar, that one might look and believe they belong to the same family. In order to facilitate classifying sharks into their appropriate families, dichotomous keys were created. It was only through a dichotomous key that these sharks could be associated to their family:

Breeding Bunnies

1.     My hypothesis stated the gene pool of the bunny population would shift and eventually the dominant genes would be the only one present.

2.     The results of the lab confirm my hypothesis, since at the end of five generations; the dominant allele was the only one remaining.

3.     At the beginning of the lab, the number of alleles for the dominant characteristic equaled the number of alleles for the recessive characteristic. In five generations, all the bunnies with recessive alleles died, leaving only the bunnies with the alleles of the dominant characteristic.

4.     Since the initial number for each allele was equal, the gene frequency of both dominant and recessive alleles was 0.5. In the next two generations, the frequency of the dominant allele increased by 0.2, meaning that the gene frequency for the recessive allele decreased by 0.2. In the fifth generation the gene frequency of the dominant allele was 1 while the other 0.

5.      Emigration and immigration affect the gene frequency of F and f  by decreasing and increasing respectively the number of alleles and therefore affecting the rate of the shift. Once there is a great amount of emigration, the size of the population decreases, and the number of alleles also chances, hence the gene pool shift occurs in a fast manner. If there is immigration, the population increases and these new members add to the gene pool, decreasing the rate of the shift. This may be simulated in the activity by adding beans (which represent alleles) and removing beans from the sample.

6.     The same trend occurred to the other group’s sample, but instead of having the dominant allele as the only one remaining, they had the recessive allele. This was due to the different circumstances in which the bunnies live in. In my activity, since they lived higher up in the mountain, the ones with thick fur (represented by FF) survived better since it was colder, whereas the other bunnies lived at the bottom where it is warmer and do not need thick fur, represented by ff.

7.     The results of this simulation are an example of evolution because of the shift in the gene pool. Since the bunnies migrated, they had to adapt to the new climate in order to survive. By that the alleles which were best suited for each new environment were the ones that remained after several generations, now differentiating the bunnies from the top of the mountain, to the ones at the bottom.

Brazilian Population

  Brazil's population age structure has been constantly
changing throughout the past years. As seen in the first figure, the population in 1990 formed almost a perfect pyramid with a high number of children and a very small percentage of the population being older than 60 years old. The second figure, already shows a significant change with and increase of people belonging to the working/reproductive section and the population older than 60 years old. This demographic change indicates both a decrease in child mortality and an increase in life expectancy.
  The third figure, Brazil's demographic pyramid in 2010 does not change much in shape, though the younger population is decreasing slightly while the older population is constantly increasing. Brazil is therefore in a period where the working group is high and there is a smaller dependency ratio.
  If the population continues to grow in this manner, the aging population will grow significantly while the school-age population will decrease significantly, affecting Brazil's economy and governmental expenditures such as social security and health care programs. Despite the population will continue to grow, though at a slower rate.

Leaves

     Other than adding to the aesthetics of plants and trees, leaves are essential for the process of photosynthesis,  hence necessary for survival. Being thin and flat, maximizes the surface area exposed to light and increases the absorption of carbon dioxide. The rate of absorption of carbon dioxide is controlled by organelles called stomata. Stomata are microscopic pores found on the epidermis of plants. They are boarded by guard cells which regulate the opening and closing of the stoma.

     The leaves in my tree have most of its stomata in the lower epidermis. It has a great number of stomata (297 per millimeter squared) and this allows more carbon dioxide and oxygen to enter the leaf. To prevent water loss due to so many pores, the leaf has a very waxy coat.

 

Adaptation and Survival

The plant I have adopted is a tree. The first great adaptation of trees is that they contain a trunk made of wood. Wood, which is a tough fiber, is used as support, allowing the plant to grow bigger and heavier. My tree's trunk is surrounded by a very thick bark that allows its survival in this environment. It's environment is the cerrado, characterized by the dry climate and due to this region is constantly prone to forest fires. The thick bark prevents the fire from burning the entire tree, and once the fire is over, the burnt bark falls off and a new thick bark is formed. 

Another property that is essential for the tree to survive in this region is it's long roots that must reach groundwater located deep into the soil. Without this groundwater, this plant would not be able to receive water since of the low precipitation rate in Brasilia. In order to conserve better the limited amount of water this plant receives, it has waxy leaves. 

What is perhaps the single most important adaptation of this tree, is the presence of seeds. Seeds can wisthand dryness and therefore they may remain dormant for sometime. And the seed dispersal contributes to the conservation of this species since it can be spread to several environments where they may eventually adapt.

My Adopted Plant

    The plant I have decided to adopt in my senior year of EAB is perhaps one of the oldest trees in school. The buildings have changed and an auditorium has been added, but this tree continues there. It is the first thing one sees when crosses the front gate and it is also responsible for providing a pleasant shade when one wants to sit outside of the classroom. Its common and scientific name are still unknown.
    What makes this tree so special is its trunk; it is very rough and contains cracks troughout. Other than this, it is covered by lichens. The lichens, which are made of algae and fungus is responsible for exchanging gases and other resources with the tree, thus having a mutualist relationship. Mutualism is a type of symbiosis where two organisms benefit from each other. Another interesting aspect about this tree is that since it is located next to another tree, it's branches are pointing toward places other than the branches of its neighboring tree. This occurs in order for the tree to have most of it's leaves exposed to the sun, and this essential for the process of photosynthesis.
   The roots are not visible but since the level of the ground around it is bumpy, the roots are probably thicks, fibrous and long. This is a common characteristic for plants in this region of Brazil, the cerrado, which is characterized by a dry climate and little precipitation. The leaves are smooth, thin, green and the veins are parallel indicating this is a monocotyledonous angiosperm.
    In the next nine months there won't be much change in growth or in the number of branches. It is probable though that seed dispersal will be visible and the tree will lose part of its leaves. This plant is not in its natural habitat, for it is located in the middle of a school with plants very close to it, something that is not very common in the cerrado where the trees are scarce and separated.

Science is a puzzle

As children we love playing with puzzles. We start with puzzles that only have ten pieces and as we complete the easier ones we try harder ones reaching up to 1,000 pieces. It may take days to finish it, but stubborn as children may be, they will not give up until it is finished. Science is also a puzzle, but without a determined amount of pieces and therefore proves to be the hardest puzzle to solve. Science involves everything humans know to exist and because of this vast area of study, this puzzle will never be completely solved. Instead, each new discovery, each new theory and each new invention add a piece to the puzzle and help create a better picture of the world we live in.

Why IB bio?

Biology is fascinating; in school it may be considered a world of its own and yet it is actually everywhere. When studying biology, one studies the environment in which he or she lives in, the history of evolution, genetics and human own physiology. Therefore it is only through biology that one can really understand his or her nature and identity. Other than being intrigued with what is studied in this class, IB biology is the perfect subject to perform several labs. Since we are required to do sixty hours of labs in this class, we have enough opportunity to experiment what has already been tested and create our own experiments.  These are some of the reasons why I chose biology as part of my IB diploma.