Introduction- This unit covers the scientific process and the characteristics of living organisms. The scientific process is made up of many practices, which may be established by each individual scientist. There is no exact order to how a person must attempt to solve a problem or answer a question. The various processes of sceintific investigation will be covered within this material.
    What characteristics actually allow us to understand that something is alive or was once living is also discussed within this unit. Basically there are six characteristics of living organisms; Cells, Organization, Metabolism, Homeostasis, Growth, & Reproduction.
 

Cells- are the basic unit structure and function of all living organisms. Organisms are composed of only one cell (unicellular) or made up of more than one cell (multicellular).

Organization- all living things are highly organized at both the molecular and cellular levels. All organisms take in materials from their environment and organize them in complex ways. The internal structure of a cell is also highly organized to perform specific functions and groups of similar cells all work together to perform specific functions.

Homeostasis - which is the maintenance of a relatively stable internal environment occurs at many levels within each organism. Body temp., oxygen-carbon dioxide levels in blood, and many other biological processes which occur within many organisms.

Energy Use (Metabolism)- is defined as the sum of all of the chemical processes that occur in the organism. During metabolism, energy is transformed from one form to another, and this energy is used to maintain their molecular and cellular organization as well as to grow and reproduce.

Growth- Living things as well as non-living things grow, but in living organisms, this growth only occurs in two ways.

A)Cell Division- which is the formation of two new cells from an existing cell.

B) Cell Development- is produced by repeated cell divisions and cell differentiation during the formation of an adult organism.

Reproduction- is the process of producing offspring that are similar to the parent organism. This either occurs through asexual reproduction or sexual reproduction.All organisms have the ability to reproduce, but it is not necessary for their survival, only the survival of the species.

There are 6 themes that recur throughout this text and biological studies. The study of life, or living organisms is called Biology. This includes the study of anything which possesses the 6 characteristics of life.

1) Cell Structure & Function- an organism is anything which posesses the 6 characteristics of life.All living organisms are either made up of a single cell ( unicellular) or made up of many cells (multicellular).

Differentiation- is a process found in only multicellulare organisms in which cells develope into different types of cells each having a specific function within the multicellular organism.

2) Stability & Homeostasis- all living organisms have several processes inside their bodies or cells that must remain stable. Several examples are;

a) Body Temperature

b) Water intake

c) Oxygen-Carbon Dioxide levels

d) Nutrients & Energy (Glucose)

e) Blood Pressure

Homoestasis- is the maintenance of a relatively stable internal environment. Many of the processes of the human body are controlled by detection centers found in the brain.

3) Reproduction & Inheritance- all organism have the ability to reproduce organisms like themselves through reproduction. DNA contains the hereditary information that is passed on from parent to offspring. The Gene is a short segment of DNA that contains the information for a specific trait that will be expressed in the offspring.

Sexual Reproduction- is the process by which two organisms share genetic information that is passed off into the offspring.

Asexual Reproduction- is the process by which a genetically identical offspring is produced taking on the characteristics of the parent.

4) Evolution- is a study of how many kinds of organisms that have lived on earth came into existence. To evolve means to change over generations and Natural Selection is the driving force behind evolution.

Natural Selection- organisms that have certain favorable traits are better able to successfully reproduce than organsims that lack these traits. There are two driving forces behind natural selection.

1) Organisms compete for natural resources such as food, water, and shelter among others.

2) Organisms that are most successful at this survival will live to reproduce and pass on their traits to offspring.

5) Interdependence of Organism- All organisms in an environment depend on each other.

Ecology- is the study of the interactions between organisms (biotic)in their environment as well as with the interactions with the non-living (abiotic) factors in that environment.

Ecosystem- is all the interactions, both abiotic and biotic, that occur within an environment.

6) Matter, Energy, & Organization- Energy and the matter that makes it up is highly organized and kept in an orderly state.

Photosynthesis- provides most all the energy for life on earth. As plants undergoe this process obtaining energy from the sun, all other organisms depend on plants to keep up their energy supplies.

Autotrophs- are organisms which produce their own food sources either through light or chemicals.

Heterotrophs- Cannot produce their own food sources, so therefore, they must consume energy by taking energy into their structures.

Although there is no single scientific method, all scientific investigations can be said to have six stages.

1) Collecting Observations
2) Forming Hypotheses
3) Making predictions
4) Performing Controlled Experiments
5) Analysis
6) Forming Theories

Collecting Observations- This involves using our 5 senses; Sight, Hearing, Smell, Taste and Touch. These senses allow us to understand and react with the environment around us. In the process of collecting this information we gain, many practices may be used such as;
a) Written- we actually write down what it is we detect in a journal or notebook.
b) Recording Devises- by using either audio or visual recording devises, we can get an accurate picture or clear sounds of what was observed.
c) Drawings- drawing representations of what it is we have observed.
d) Sampling- collecting specimens or samples of what we have observed which may be further evaluated in a lab environment.

The Hypothesis- A hypothesis is a testable statement. This statement is often found in the form of a question, or just a plane statement which can be tested through further scientific investigation. We use observations, previous knowledge, past experiences, research findings and others work or findings to base our hypothesis.

The Prediction- A prediction is a statement telling what will happen through our scientific process prior to it actually happening. Most often this may be recognized by finding the "If - Then" statement.  ie. If we use miracle grow plant fertilizer on our experimental group, then the tomatoe plant in the experimental group will grow better than the tomatoes in the control group.

Experimenting- This is a process which allows us to support or refute(disprove) our hypothesis. This may be accomplished in a number of ways. Observations may be used as an experiment type mode to validate or refute the hypothesis. Often times we like to use a controlled experiment which lets us evaluate specific factors and see what affect they will have on the outcome of the experiment or process to be tested.
    Parts of the Controlled Experiment.

a) Controll Group- this group is the one which occurs most naturally. We want this situation to be as real to life as possible
b) Experimental Group- This group will have one factor that is different from the control group.
    In both these groups all factors need to be identical except for the one which is different in the experimental group.
c) A factor is any individual part of an experiment, such as light, water, temp., soil type, pot size (ect.)
d) Dependent Variable- this is the one factor in both groups that will be measured so we can gain our data from the experiment.
e) Independent Variable- This is the one factor in the experimental group which is different from all other factors in the experiment.

Analysis- This part of the scientific process involves looking at the data we obtained from the experiment, comparing and seperating out the important information so we can see if our experiment supports or refutes the hypothesis.

Theorizing- After we analyze our data we may develop a theory about how experiments in the future will come out. This theory may change if data from future experiments turns up differently. With all theories, we must continue to experiment time and time again to make sure our theory is indeed valid.

Validity- This only occurs when we make many test and the results always come up close to being the same all the time. With any experiment there should be a tolerance rating.

Tolerance Rating- gives a small variance or range in which our data may fall. Very seldom does any experiment come out exactly the same when done by common people or students. As long as our numbers fall in a certain tolerance range, they are said to support the orignal findings.

     In order for us to classify something as an organism we must understand what the characteristics for life or properties of life are. Six areas are targeted in chapter one which are discussed in length below.

Organism- An organism is anything which is or was living and  posesses the properties of life or at one time posessed the properties of life....
 
Cells

Organization

Energy Use(Metabolism)

Homeostasis

Growth

Reproduction

Cells
    All living things are composed of one or more cells.
Cell- is the basic unit capable of all life functions and maintains the properties of life. Cells are also organized in the way they are structured. All cells are composed of some similar parts.
        a) cell membrane or cell wall. is the structure which surrounds each cell. This structure controls what enters and exits the cell. Animals only have a cell membrane, all plants have a cell wall in addition to the cell membrane. Some other organisms have a cell wall composition like bacteria and fungi.
                1) Selectively Permeable- a cell membrane is selectively permeable, which means it allows some materials to enter or exit the cell while stopping other materials from passing through.
        b) cytoplasm- this is everything which is located inside the cell membrane. It contains cytosol, the liquid portion of the cytoplasm and organelles.
        c) organelles- the word means "tiny organ" and these tiny structures inside the cell do a specific job for the cell.
                1) Nucleus- is just one organelle in the cell and it is the control center for the cell, controlling all activities that the cell may undergo.

    Basically there are two types of cells, prokaryotic and eukaryotic.
Prokaryotic cells have no nucleus and few if any organelles.
Eukaryotic cells have a nucleus and many organelles and these types of cells carry out more complex functions than do prokaryotic cells.

Tissues- tissues in organisms are formed from a group of similar cells that are all working together to do one particular job or function. These cells are basically the same size, shape, and of the same structure.

Organs- are formed from a group of different tissues. Each tissue in an organ are different, but all tissues are working together to do the job of the organ. Example ( Heart) Is made up of muscle, nervous, blood, and fat tissues but they all work together to cause the action of the heart pumping the blood.

Organ System- is a group of different organs, all working together for a particular function. Example ( Circulatory System) The heart, blood vessels, lungs and brain are all working together to coordinate the movement of nutrient material, oxygen and chemicals around the body of an organism.

    As we look back at the organization of cells and how these cells are put together to form the organism, it is easy to see why cellular organization is a very important porperty of life.

As living things grow, there are only two ways in which this growth occurs.

Cell Division- Which is the development of new cells through reproduction as new cells are produced from existing cells.

Cell Development- this is the process by which adult organisms arise, in repeated cell division and cell differentiation.

Microscope Review Sheet

Chapter 1 Test Review