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Biology
__Biology__ is the study of life and living organisms. There are five unifying principles that are the fundamentals of modern biology:

1. //Cells are the basic units of lif//e 2. //New species and inherited traits are the product of evolution// 3. //Genes are the basic unit of hereditary// 4. //An organism will regulate its enviro////nment to maintain a constant and stable condition// 5. //Living organisms consume and transform energy//

YouTube link for "The Biology Song": // http://www.youtube.com/watch?v=aynclw6TXeE //

 red blood cells

evolution of giraffes human genes polar bear habitat transforming energy

Living Things

 * **Made up of Cells - cells are the basic building blocks of life**


 * · Unicellular organisms are life-forms consisting of only one cell
 * · The majority of life is unicellular (mostly bacteria)
 * · Unicellular organisms are either prokaryotic or eukaryotic
 * · Usually formed by asexual reproduction (comes from the same parent)
 * · Examples of unicellular organisms:
 * o Bacteria
 * o Amoeba
 * o Protozoa
 * o Viruses
 * o Sponges


 * · Multicellular organisms are living things made up of two or more cells
 * · These organisms come from two different parents (sexual reproduction)
 * · Examples of multicellular organisms:
 * o Humans
 * o Bears
 * o Frogs
 * o Birds
 * o Fish


 * Here's a video about unicellular and multicellular organisms:**
 * An Introduction To Unicellular And Multicellular Organisms**


 * **Based on Universal Genetic Code**

The **__universal genetic code__** is a set of rules by which information encoded in genetic material (like DNA or mRNA) is turned into proteins and amino acid chains by living cells. All living things (with a few exceptions) are based on that code. DNA (__Deoxyribonucleic acid__) is the part of the universal genetic code that determines inherited traits in organisms. DNA gives us our traits: things like eye color, hair color, and our genes.

Another part of the Universal Genetic code is mRNA, or Ribonucleic acid. RNA and DNA are very similar, but DNA has two strands (see picture) that make up one molecule, and RNA has just one strand. RNA has many functions but a major one is bringing information from ribosomes to DNA strands. Both RNA and DNA are parts of the Universal Genetic Code

This is a model of a DNA strand. Here is a model of an RNA strand. These are the differences between DNA and RNA in there physical appearance.

This is a link for a video about the genetic code.

http://videos.howstuffworks.com/hsw/5997-introduction-to-the-genetic-code-video.htm


 * **Obtain & Use Materials & Energy**


 * In order to have the ability to do work, __energy__ needs to be released
 * Energy is released from the intake of food
 * Some animals hunt (carnivores)
 * Some animals eat plants (herbivores)
 * Some animals eat both meat and plants (omnivores)
 * __Energy__:
 * Energy can be released from Cellular Respiration
 * Cellular Respiration: the process where food breaks down in the organism and energy is released (Water + CO2 released)
 * Metabolism: combination of **all** chemical reactions in an organism (anabolism and catabolism)
 * Anabolism: making larger substances from smaller ones (photosynthesis)
 * Catabolism: breaking down a larger substance into a smaller substance (cell respiration)



**grow-**to naturally develop by increase in size. All organisms grow during at least part of their life cycle. **develop-** changing physically and progressing to maturity. Advance and elaborate. All the changes that occur as a living thing grows.
 * **Grow & Develop**

here is a youtube video of fruit developing and a plant growing: http://www.youtube.com/watch?v=c0En-_BVbGc
 * [[image:3170_animal_genius_pigeons-5_04700300.jpg height="180" caption="This photo shows how a bird goes from a little baby to an adult. As you can see there are many physical differences that occur'd as the bird grew and developed. "]] ||
 * This photo shows how a bird goes from a little baby to an adult. As you can see there are many physical differences that occurred as the bird grew and developed. ||


 * [[image:lifecycle.jpg height="306" align="center" caption="This is just another example of growth and development."]] ||
 * This is just another example of growth and development. ||

sexual: 2 parents; offspring obtain characteristics of both parents asexual: 1 parent; offspring and parent have identical characteristics __Sexual Reproduction__: When two cells reproduce to make a different offspring. It results in increasing genetic diversity of the offspring. Characterized by two processes: - Meiosis: halving of the number of chromosomes. - Fertilization: combination of a sperm and egg cell and restoration of the original number of chromosomes. __Asexual Reproduction__: When a single cell divides to create an identical offspring. It is a form of reproduction that does not involve meiosis or fertilization.
 * **Sexual vs Asexual Reproduction**
 * __Definitions:__**

The example animals used in the following notes were snails. - Sexual reproduction is proven to take more time and energy than asexual reproduction. - It was proved that snails that reproduced sexually accumulated harmful DNA mutations at half the rate of asexual snails.



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 * **Internal vs External Stimuli**

 Internal and external stimuli are quite different. Stimuli can come in many shapes and sizes. The general definition for the broad term of “stimuli” is defined as events in the environment that influence changes in behavior. Stimulus can cause you to want to do something, or feel something you hadn’t felt before.

 Internal Stimuli is something on the inside of the organism that creates behavior. Such an example would be hunger. Hunger is felt in the stomach of the organism and makes the organism want to go eat or find food. This feeling of hunger is further exacerbated if food is smelt by the nose (external stimuli).  An external stimulus is something on the external part of the organism that creates or incites a feeling within the organism. Such an example is heat on the outside of the organism. When the organism feels the heat, the organism also feels the feeling of burning. A fruit and the smell of a fruit can also be an external stimulus.


 * **Homeostasis**


 * **Evolve Over Time**

By definition, the word evolve means to develop or work out. When dealing with Biology it often means the way an organism develops itself based on it's surroundings. For example, mankind has developed dramatically with the passing of time as you can see in the photo shown below. -Over time an organism will adapt to their environment. Adaptation is a trait that in this case makes a living thing better able to survive in it's environment. Ex.) In the North Pole, Polar Bears have a think fur to be able to cope with the frigid climate. Another example is that many reptiles often need to be able to blend in (camouflage) with their surroundings to avoid being eaten by their predators.

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Over time mankind evolved from ape to human.