UNIT 1: The Science of Life BIG IDEA: Biology is the study of living things and their characteristics, using the tools of science

Part1 – How do we know if something is alive?

Characteristics of Life 1.Cellular Organization 2.Use Energy for Metabolism 3.Growth and Development 4.Respond to Stimuli 5.Homeostasis 6.Reproduce 7.Heredity

Cellular Organization A cell is the smallest unit capable of all life functions Levels of Organization: Cells  Tissues  Organs  Organ Systems  Organism

A B C

Use Energy  Energy is needed to run life sustaining chemical reactions, like movement, growth, and repair.  Metabolism is the sum of all these reactions.

Metabolism Metabolism manages the energy and material resources in a cell. There are two basic types.

Catabolic Break down large molecules Releases/ Stores energy For example, cellular respiration is the process that breaks down sugar molecules into small energy storing molecules

Anabolic Build larger molecules Uses energy For example, protein synthesis is the building of large proteins from smaller molecules called amino acids.

Growth and Development Growth: increase of living matter (making more cells) Development: change into mature adult

Response to Stimuli Stimulus: a change in the environment Organism respond and react to changes around them For example, animals run from predators. Think of stimuli you react to.

Homeostasis Homeostasis: to maintain the same internal environment in response to changes in the external environment What internal changes does your body regulate?

Homeostasis Some examples: temperature, water and salt levels, blood sugar levels

Reproduction Process by which organisms make more of their own kind Necessary for the survival of the species Asexual and sexual

Heredity Organisms pass hereditary information in genes to their offspring. Genes are encoded in the molecule called DNA Allows for adaptations and changes through time

Tell what characteristics of life each item has. Seed Volcano Chicken egg Bread dough Moldy bread A branch off a tree

DO NOW Think of a characteristic of life that a nonliving object might display and explain what it is.

Tools Used by Biologists Study Living Things A.Scientific Method B.Microscope C.Metric System

Scientific Method

Identify the Problem/Purpose Often developed from observations made of nature.

Hypothesis and Prediction A hypothesis is a proposed explanation for the stated problem. It must be testable! Then scientists can make a prediction for the outcome of your experiment. “Predictions can be stated as “If…. Then…” statement.

Use a controlled experiment to test your hypothesis. Keep all the test conditions the same except for the variable you are testing Design an Experiment

Collect data in the form of measurements and observations about experiment. Reported in metric/SI units Record Observations/Data/Results

Two types of Data Quantitative Data that uses numerical values, measurements E.g. mass, temperature Qualitative Data that uses descriptions. E.g. color, odor, texture

Explain your observations, data, and results. List the main points that you have learned. Was your hypothesis correct? Analysis

Answer your problem/purpose statement. What would be the next question to ask? * Remember! Your hypothesis is never PROVEN true. It is either rejected or not rejected. Conclusion

Share the Information Publish your findings in journals.

Theory Many accepted hypotheses that explain a similar topic form a theory. May be revised or replaced!

Designing a Controlled Experiment A controlled experiment compares a control group against an experimental group.

A control group provides a normal standard that is used to compare with the experiment group.

The experimental group is the same as the control group, except for the one variable that is being tested.

The independent variable is the factor that is being tested, which changes from the control group to the experiment group. It is chosen by the scientist.

The dependent variable is the result of the experiment and is the factor that is observed and measured. It depends on what is tested.

Why does a good experiment control for variables?

Metric System SI units

Scientists Report Measurements as… Mass = Volume = Length = gram liter meter

PrefixAbbreviation Factor of Base Unit gigaG1,000,000,000 megaM1,000,000 kilok1,000 hectoh100 dekada decid0.1 centic0.01 milim0.001 microμ nanon Angstrom**Å picop

Converting SI units To move from a LARGER unit  SMALLER unit => MULTIPLY To move from a SMALLER unit  LARGER unit => DIVIDE Multiply/Divide by POWERS OF 10

SI units are in POWERS OF 10, to multiply move the decimal to the right. to divide, move the decimal to the left.

Move the Decimal 1.0 kg = g = 1,000,000.0 mg 1 mm = 0.1 cm = m = km kg = g = mg