Introduction to Biology

Science begins with… –Observations- any fact using the 5 senses –Data – information gathered during an experiment. Two types of observations/data: Quantitative – Data that involves numbers. Qualitative – Data that has descriptions and can’t be measured. Inference – prediction based on prior knowledge. –Ex: The balloon will fall to the ground.

Conducting an Experiment Hypothesis – An answer to a scientific question (educated guess of outcome of experiment). Controlled Experiment: procedure to test a hypothesis. –Has only ONE manipulated variable

Different Types of Variables Variable – factors that can be changed Controlled Variable (control group) – the variables that are kept the same. Manipulated Variable/INDEPENDENT– the variable that is changed. Responding Variable/DEPENDENT- variable that changes as a result of manipulated variable.

Mrs. Moon wants to conduct an experiment to test the effect of plant growth based on the amount of water received. She does the following: Obtains 3 seeds- tomato, sunflower, violet Places each in same amount and type of soil. Places each in same type of pot. Gives tomato 1 cup water, sunflower 2 cups water and violet 3 cups water. IS THIS A CONTROLLED EXPERIMENT?

Steps to a Controlled Experiment 1. State Problem 2. Gather Information 3. Hypothesis 4. Conduct Experiment 5.Record Data 6.Analyze Data 7.Conclude 8.Publish or repeat

Measurement in Science

Why the Metric System? Metric Measurement : International system of Units or “SI” –Universal – used all over the world –Based on multiples of 10 –Easy to convert

What is Measured? Unit of Measure- ment Abbrevia- tion Tool for Measuring LengthMeterm Meter Stick or ruler VolumeLiterl Graduated cylinder MassGramgBalance TemperatureCelcius°C Thermo- meter

Common Prefixes: Kids Have Dropped Over Dead Converting Metrics 1. Kilo (k) 2. Hecto (h) 3. Deka (dk) 4. Unit (meter, liter or gram) 5. Deci (d) 6. Centi (c) 7. Milli (m)

Microscopes Leeuvenhoek – invented the first microscope Compound Light Microscope: produces a magnified image by focusing visible light rays using 2 lenses. can observe dead or alive specimen Specimen must be thin enough for light to pass through. Can be stained to show more detail

Microscopes continued Stereo Microscope –used when viewing large specimen (wing or leg of insect) –Light does not pass through object. Electron Microscope – focus beams of electrons to get image magnified Magnifies 1000x more than the light microscope.

The Theory of Spontaneous Generation The idea that life arises from non-living matter. Theory was discredited by Redi’s experiment with meat in jars: –Put meat in 2 jars. Covered one jar and left one open. Flies were able to get to the meat of the open jar and maggots appeared. –No flies and no maggots on jar that was covered. –Concluded that maggots came from flies not meat.

Characteristics of Living Things

What makes something living???? No one single characteristic makes an organism living. Instead, living things share several characteristics. These characteristics include the following:

Made of cells. Cell- basic unit of all life Unicellular- made up of only 1 cell Multicellular- made up of more than 1 cell.

Reproduce. Two types: Sexual- egg and sperm from 2 different parents unite to produce offspring. Asexual- offspring forms from one parent. (ex: bacteria)

Contain DNA Determines the inherited traits of every organism.

Grow and Develop. Each organism has a life cycle

Obtain and Use Materials and Energy. Autotroph- makes their own food. Heterotroph- does not make their own food.

Respond to their environment. Organisms live in constantly changing environments. Many variables change from day to day and season to season. Each organism responds to these changes in its own way.

Maintain a Stable Internal Environment. Homeostasis- The process by which organisms keep their internal conditions stable.

Change over time- Evolve. Although individual organisms experience many changes during their lives, the basic traits they inherited from their parents usually do not change. As a group, however, any given kind of organism can evolve, or change over time.

Levels of Organization From the bottom to the top!!

Molecule Atoms and molecules of which an organism is made.

Cells Basic unit of life.

Tissue A group of cells that perform the same function.

Organ A group of tissues that perform the same function.

Organ System Several organs working together to perform a specific function.

Organism All the organ systems of the body functioning with one another.

Population A group of organisms of the SAME SPECIES living together.

Community All the biotic factors (populations) living together.

Ecosystem All the biotic (living) AND the abiotic (nonliving) factors of the environment.

Biosphere All of the ecosystems combined together.

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