What is Biology?
Biologists Study the Interactions of Life Living things do not live in isolation. They interact with their environment and depend on other living/non-living things for survival.
Biologists Study the Diversity of Life
Why should biologists study an organism s environment?
Biologists Study Problems and Propose Solutions Biological research can lead to advances in medical treatment, disease prevention in humans and other organisms and preserve organisms that are in danger of extinction.
Invasive Species
Revealing Misconceptions What is the difference between an organism that is native to an area and one that is not? How could we figure out whether a species of a particular plant is native to a given area?
Characteristics of Living Things Anything that possesses ALL of the characteristics of life is known as an organism. All living things: 1) Have an orderly structure 2) Produce offspring 3) Grow and develop 4) Adjust to changes in the environment
1) Living Things are Organized Every organism is made up of one or more cells. Each cell (whether animal or plant) has a very organized internal structure. Cells of multi-cellular organisms work together to form the different parts of a living system.
2) Living Things Make More Living Things Organisms don t live forever and for life to continue, they must replace themselves to ensure the survival of their species.
3) Living Things Grow and Develop Growth: Increase in the amount of living material and formation of new structures. Development: All of the changes that take place during the lifetime of an organism.
4) Living Things Adjust To Their Surroundings (Adapt & Evolve) Anything in an organism s external or internal environment that causes an organism to react is called a stimulus. Ex: temperature change, presence of a prey, noise, ingestion of a foreign particle, etc. A reaction to a stimulus is a response.
4) Living Things Adjust To Their Surroundings (Adapt & Evolve) Homeostasis: Regulation of an organism s internal environment to maintain suitable conditions for its survival. Ex: Sweating, shivering Homeostasis occurs in all living things. Without homeostasis, organisms die. Homeostasis requires energy just like growing and reproducing. Organisms get energy from the food they eat.
4) Living Things Adjust To Their Surroundings (Adapt & Evolve) Adaptation: Inherited structure, behavior or internal process that enables an organism to respond to environmental factors and live to reproduce. Evolution: Gradual changes in a species through adaptations over time.
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Methods of Biology Scientists use many different methods to answer questions, but all scientific inquiries share some common methods. Scientific Method: 1. Observation 2. Ask a question 3. Hypothesis 4. Experimenting 5. Analyzing 6. Forming a conclusion/theory
Experimenting Controlled Experiments: -have a control group and an experimental group Control group: group not receiving any experimental treatment. It is the standard to which results are compared to. Experimental group: group receiving the experimental treatment. Ex: A scientist wants to test the effect of a new drug for bacterial ear infections. The scientist prepares two groups of bacteria: one that will not be tested with the drug (the control) and one that will be subjected to the drug (the experimental group). The scientist then compares both groups of bacteria after the experimentation has occurred.
Controlled Experiments Only one condition is changed at a time. The condition that is tested in an experiment is called the independent variable. The result of manipulating the independent variable is called the dependent variable. Ex: A student wants to learn how fertilizer affects the growth of soybeans. The student hypothesizes that the presence of fertilizer will lead to an increase in plant growth. The student then puts fertilizer in the soil of the experimental plants, but not in the soil of the control group. The presence of fertilizer is the independent variable and the growth rate of the plant is the dependent variable.
Try This! Describe the roles of a control, independent variable and dependent variable.
Experimenting: Data Gathering Experimental results are also called data. There are two kinds of data: -Quantitative (numerical data such as counts, masses, volumes, lengths, etc. represented in graphs/tables) -Qualitative (written descriptions if what scientists observe with their senses: what they see, touch, hear, smell, taste)
Team Challenge 1. Break your team up into 2 sections. 2. Each section must list quantitative and qualitative information about 3 common animals. 3. You will then present your data to the other section who will then try and guess your 3 animals. For each correct answer, the entire team receives 1 point.
Analyzing THE MOST IMPORTANT STEP After a careful review of the results, a scientist must come up to a conclusion: Was the hypothesis correct? Are more data needed? Scientists then compare their findings to those of published studies on the same topic. They compare methods and results while looking for any form of bias (personal expectations, beliefs, sources of funding).
Reporting Results Biologists report their results in scientific journals where they can then be examined by other scientists. Verifying Results Other scientists will try and verify the results of published experiments by repeating the procedure. If they obtain the same results, the study/theory is supported that much more and it is accepted by the scientific community.
What is a theory? An explanation of a natural phenomenon that is supported by many scientific observations and experiments over a long period of time. Ex: the theory of evolution, the Big Bang
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Organizing Information in Biological Experiments Measuring in the International System Using the metric system allows scientific research to be understandable to scientists around the world! It is easy to use as it only uses a few basic units. We do not use the imperial system (US standard)
Ethics The knowledge gained through scientific research is never inherently good or bad. Scientists might not consider all the possible applications for the products of their research. Society as a whole must take responsibility for the ethical use of scientific discoveries.
Not all questions can tested scientifically Some questions are simply not in the realm of science. Ex: Do black cats bring bad luck to those they cross? -Must ask yourself what is bad luck? How would you distinguish between bad luck caused by the black cat and regular bad luck? Once you examine the question, you realize that you cannot devise a controlled experiment that would yield valid data.
Can technology solve all problems? Technology has benefitted humans in numerous ways such as increasing the production of food. Technology also has its down sides. The fertilizer used to increase crop production has caused the destruction of coral reefs and excessive growth of algae.
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