Living Things
The Nature of Science
Levels of Organization
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Element – atom
Molecules
Cells
Tissues
Organs
Organ systems
Organism
Species
Populations
Communities
Assumptions in Science
 Natural causality
 All events are due to natural causes and are potentially
within our ability to understand.
 Uniformity in space and time
 The laws derived from the study of nature are the same
everywhere and have been the same for billions of years.
 Common perception
 Everyone generally perceives events similarly.
The Scientific Method
 Way in which scientists study things in the world.
 Observation/Problem
 Question
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Do Background Research
 Hypothesis
 Null Hypothesis
 Prediction
 Experiment
 Collect Data
 Analyze Results
 Conclusion
sciencebuddies.org
The Experiment
 Variable
 A factor that affects an observation/changing quantities
 Independent Variable – something that is changed by the
scientist
 Dependent Variable – factor that is measured and is
dependent on the independent variable
 Standarized /Controlled Variables – aspects of an
experiment that remain the same
 Control Group
 Used to rule out other possible variables
 Do not receive experimental treatment
Scientific Method
 The results of an experiment must be able to be
repeated by other researchers.
 An experiment must be communicated thoroughly
and accurately.
 Why is this important?
Scientific Theory
 General explanation of important natural phenomena,
based on extensive and reproducible observations.
 principle or a natural law
 Ex. Atomic theory (all matter is composed of atoms)
 Ex. Theory of gravitation (objects exert a law of
attraction for one another)
 Ex. Cell theory(all living things are composed of cells)
 A theory can be modified or falsified.
The Theory of Spontaneous Generation Abiogensis
Francesco Redi’s Experiment – 17th century
facstaff.gpc.edu
Malte Andersson’s Widowbird
Experiment
Male long-tailed widow bird.
sanparks.org
Female long-tailed widowbird.
10000birds.com
What Do You See?
Orphrys apifera. floralimages.co.uk
What Do Glowing Pigs and Jellyfish
Have in Common?
Biodiversity
 Refers to the total number of species within a given
region and the resulting interactions among them
www2.warwick.ac.uk
sciencelearn.org.nz
3 Domains of Life
5 Kingdoms
 Eukaryotes (have
membrane-bound
organelles)
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1. Plants
2. Fungi
3. Animals
4. Protists
 Prokaryotes (lack
membrane-bound
organelles)
 5. Monera/Bacteria
 Includes bacteria and
members of archaea
What is a Living Thing?
Theory of
Evolution
Charles Darwin
Alfred Russel Wallace
 Formulated by Charles Darwin and Alfred Russel
Wallace in the mid-1800s
 States that modern organisms descended, with
modification, from preexisting life-forms
 Evolution - Change in the genetic makeup of a species