From Wikipedia, “A biome /ˈbaɪoʊm/ is a community of plants and animals that have common characteristics for the environment they exist in.”  There are two categories of biomes, terrestrial biomes and aquatic biomes.  In these two general categories there is a wide variety of biomes.  In this assignment, I have selected, and will contrast two terrestrial biomes: the savanna, and the tropical rain forest.

A savanna is an open grassland, the trees in a savanna are sufficiently spread so that they do not create a canopy blocking direct sunlight to the soil.  However, this does not mean that they do not have high tree density, the trees are simply more regularly spaced than in tropical  forests.  Savanna covers about 20% of the earth’s surface, and despite the dryness, the savanna can support a lot of life.  Grazing or browsing animals are common inhabitants of a savanna.  The temperature year-round generally averages in the high 70’s (68-86 F), which is helpful to the organisms living there.  One of the challenges that faces the inhabitants of a savanna, is the danger of wildfires, which are common in a savanna.

Unlike the savanna, tropical rain forests have a canopy of trees that almost entirely blocks direct sunlight to the soil, this provides opportunity for organisms very different from those who occupy a savanna.  Tropical rain forests do not encounter a dry season, and encounter a lot of rain (avg. of 60 mm per month) year round.  Tropical rain forests are withing 10 degrees (north or south) of the equator.  The temperature is fairly consistent year round- rarely getting above 93 degrees Fahrenheit, and rarely getting below about 68 degrees Fahrenheit, which is pretty consistent year round, however, not as consistent as the average savanna temperature range.

The two biomes are significantly different from one another and the inhabitants of each face different challenges every day.  The organisms in each biome are equip to survive the conditions of  that biome.

“Is cancer alive? Why aren’t doctors able to uncover a single cause or cure for it? Why isn’t cancer contagious?”

The human body is one big complicated system.  Many genes control different growth factors, and other purposes cells must carry out within this system.  A system this delicate and complicated, surfaces a lot of opportunity for things to go wrong.  Things go wrong when simple mutations occur in these genes, which prevent them from functioning properly.  Oncogenes are cancer causing genes, which are initially caused by simple mutations.

So, is cancer alive?  No, the cancer tumor itself is not alive apart from the living organism.  The tumor is made of abnormal tissues initially caused by mutations of genes that control essential functions of the cell.

Doctors are unable to develop a single cure, because they have not identified the single cause.  Doctors, scientists, and bio-technicians, are getting closer everyday to uncovering and understanding the single cause for cancer.  As of now, it is clear that it is the combination of many different mutations.

Why isn’t cancer contagious? A small percentage of cancers are actually hereditary, however, cancer is not contagious like a flu.  Cancer happens within the organism, caused by several different factors that produce excess proteins and tissues.  It is, in a sense, like a machine that develops minor issues that continue to build and expand and, over time, create a major, and possibly fatal, issue.  Cancer is not a virus that can be spread by contact, but rather, a disease caused by mutations in this complicated system.

Joking aside, why are men far more likely than women to be colorblind?

Men are more likely to be colorblind than women, why?  It is all about genes.  Our chromosomes come in pairs, we get one from each parent.  The female gamete has two X chromosomes, and the male gamete has an X and a Y chromosome.  For the child to be female, it must get an X chromosome from the mother, and an X chromosome from the father.  For the child to be male, they must get the X chromosome from the mother and the Y chromosome from the father.  The child will get an X from the female gamete regardless.

The genes for colorblindness are on the X chromosome.  If a female has something wrong with one of her X chromosomes, she has another to back it up, she would thus need two damaged X chromosomes to inherit colorblindness.  Males, however, only have one X chromosome, so if this chromosome is damaged, there is not another one to back it up.  Women have a chance of inheriting colorblindness, however, men are 50% more likely than women to inherit colorblindness.

“You are probably taller now than you were 4 years ago. What, specifically, caused you to become taller? Explain what happened on a cellular level.”

The cell is the basic unit of life.  Anything smaller than a cell; unable to perform the jobs of the cell, is not a form of life.  Cells are what larger organisms are made of.  Having the ability to understand life on a cellular level allows us to understand the larger organisms.

In terms of human growth, what happens on a cellular level?  Over a time period of, in this case, 4 years, what happens inside a child’s body that causes them to grow taller?  Cells themselves do not grow beyond a certain point, as they would get so large that the systems inside the cell would no longer function properly.  Think of an infant, if they had the same cells from infancy to adulthood, and the cells just grew, the cells would be incredibly large and unable to function properly.  What happens?  The cells actually duplicate.  The cells split, through a process called mitosis, which creates a genetically identical cell.

There are two different phases of the cell cycle, the mitotic phase which is where mitosis occurs, and the inter-phase, during the times when the cell is just carrying out the job it is designed to do.  The cells know what phase to be in because they receive messages from other cells.  The outer membrane of the cell is covered with receptors, that receive messages that “tell” the receiving cell about other cell activity, and this tells the cell what phase it should be in.  The cells in an organism work together systematically to carry out growth, healing, and many other purposes of the organism.

Proteins are involved in just about everything a living organism does.  There are many different kinds of proteins, each performing a different series of applications.  Transport proteins serve as transportation in an organism, they get things from one point to another.  The 2 proteins actin and miocin, give the muscle fibers the ability to contract.  Proteins are involved in more than just muscle. Motor proteins move the flagellum in the cilium of a micro organism, such as bacteria.  A majority of motor proteins have the ability to modify their shape in a series of repeatable ways and this is where motion comes from.  These few tasks, along with the tasks of the other 10’s of millions of different kinds of proteins happen on a molecular scale inside the smallest form of life, the cell.

Carbohydrates also play a crucial role in every organism.  A carbohydrate is a molecule consisting 3 different atoms: carbon, hydrogen, and oxygen.  Carbohydrates, along with fats, store energy (calories) for an organism.  It is crucial that living organisms have this means of storing potential energy.

While proteins and carbohydrates perform completely different tasks, they are both essential to all living organisms.