Chapter 1 - Biology
independent variable
(manipulated) changed by the scientist
dependent variable
(responding) reacts to independent variable
Common Metric Units
- Length (meter, centimeter, millimeter, kilometer) - Mass (kilogram, gram, milligram, metric ton) - Volume (liter, milliliters, cubic centimeters) - Temperature (degrees celsius)
What characteristics do all living things share?
- Made up of basic units called cells - Based on a universal genetic code - Obtain and use materials and energy - Grow and develop - Reproduce - Respond to their environment - Maintain a stable internal environment - Taken as a group, they evolve (change over time)
DNA
- a universal genetic code written in a molecule - where the complex information organisms need to live, grow, and reproduce - this information is copied and passed from parent to offspring - deoxyribonucleic acid
scientific notation
- allows us to write very small or very large numbers more easily - a given number is a product of two numbers: a coefficient and 10 raised to a power ex. 756,000,000,000 = 7.56 x 10 to 11th power ex. .000519 = 5.19 x 10 to -4th power
homeostasis
- the process all living organisms perform when they expend energy to keep conditions inside their cells within certain limits - most organisms need to keep conditions inside their bodies as constant as possible even when external conditions change dramatically
Cells
- the smallest units considered fully alive - grow, reproduce, and respond to their surroundings - are complex and highly organized
goals of science
-provide natural explanations for events in the natural world -explanations are based on evidence, NOT BELIEF - they are tested for more evidence
1 meter
100 centimeters 1000 millimeters
1 kilogram
1000 grams
1 metric ton
1000 kilograms
1 kilometer
1000 meters
1 gram
1000 milligrams
1 liter
1000 milliliters 1000 cubic centimeters
Distinguish between an experimental group and a control group.
A control group is used for comparison to an experimental group. The control group does not contain the independent variable, only the experimental group does.
accepted value
AV: correct value based on reliable references
experimental value
EV: value measured in the lab
Metric Prefixes
King Henry Died Once Drinking Chocolate Milk Kilo (1000 base units) Hecto (100 base units) Deka (10 base units) One (base unit) Deci (0.1 base unit) Centi (0.01 base unit) Milli (0.001 base unit)
How does an observation about an object differ from an inference about that object?
Observation involves the act of noticing and describing events or processes in a careful, orderly way. Scientists use observations to make inferences. An inference is a logical interpretation based on what scientists already know.
percent error
PE: the absolute value of the error, divided by AV, multiplied by 100 and expressed as a percent = |EV-AV| / AV all times 100
Where do new ideas come from?
Scientific Attitudes: Curiosity (leads to new questions) Skepticism (questioning ideas) Open-mindedness (willing to accept new ideas) Creativity (creative thinking)
What is the scientific method?
The Heart of Science 1. Observe and ask questions 2. Hypothesis 3. Designing a controlled experiment 4. Collect and Analyze Data (must avoid errors here) 5. Draw Conclusions (evaluate your hypothesis - do you need to change anything)
Explain why you cannot draw a conclusion about the effect of one variable in an experiment when the other key variables are not controlled.
There needs to be a control so you can monitor change and have a reference to compare to.
metric system
a decimal system of measurement used in science whose units are based on certain physical standards and are scaled on multiples of 10
inference
a logical interpretation based on what you already know
bias
a point of view that is personal rather than scientific
hypothesis
a scientific explanation for observations that can be tested to support or reject
stimulus
a signal to which an organism responds ex. weather
asexual reproduction
a single organism produces offspring identical to itself
What is a scientific theory?
a well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations - can be revised or replaced by new explanations as new evidence
controlled experiment
an experiment in which only one variable is changed
science
an organized way (process) of gathering and analyzing evidence about the natural world - means knowledge - refers to the body of knowledge gathered y scientists throughout the years - trying to explain the world in terms of events and processes being observed
100 degrees C
boiling point of water
sexual reproduction
cells from two parents unite to form the first cell of a new organism
error
difference between experimental and accepted value = EV - AV
0 degrees C
freezing point of water
experimental group
has independent variable
precision
how close a series of measurements are to one another (dartboard - bullseye = accurate)
data
information gathered from an experiment
qualitative data
involves description and physical aspects
quantitative data
involves numbers
accuracy
measure how close a measurement comes to the actual or true value of whatever is measured
control group
no independent variable - used for comparison to the experimental group
nano (n)
one-billionth base unit 0.000000001 b.u.
micro (u)
one-millionth base unit 0.000001 b.u.
measurement
quantity with both a number and a unit example: 51 km; 7.62 cm; 451 mL
peer review
scientific papers are reviewed by anonymous, independent experts (look for oversights, unfair influences, fraud, or mistakes in techniques or reasoning)
observation
the act of noticing and describing events or processes in a careful, orderly way - involves more than just looking
metabolism
the combination of chemical retains through which an organism builds up or breaks down materials
biology
the study of life
dimensional analysis
using conversion factors to go from one unit to another
evolve
when groups of organisms change over time, over generations