Download Biology: Scientific Study of Life

Biology: Scientific Study of Life
What is science?
 What is life?
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Characteristics of Living Things
1. Living things are highly ordered (or organized).
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Atom
Molecule
Organelle
Cell
Tissue
Organ
Organ System
Organism
Population
Community
Ecosystem
Biosphere
Characteristics of Living Things
2. Metabolism - living things must gather and
use energy to maintain order.
3. Motility - self propelled motion
4. Responsiveness - response to their
environment. (e.g. detect cold, heat, food,
water, etc).
Characteristics of Living Things
5. Reproduction suite of mechanisms by which they
give rise to new organisms.
6. Development - changes from conception to sexual
maturity (and even to death).
7. Genes - units of inheritance composed of DNA.
8. Living things evolve - change over time.
9. Adaptiveness - over time genetic modifications
that allow organisms to cope with their
environment .
Two underlying principles
critical to science
1) Causality - the occurrence of events is due
to natural causes
2) Uniformity - the laws of Nature always
have operated and always will operate in
the same way
Scientific Reasoning
1. Inductive Reasoning - reaching a
conclusion based upon a number of
observations (going from the specific to the
general).
2. Deductive Reasoning - one reasons from
the general to the specific (analyzing
specific cases based upon a pre-established
general principle).
The Scientific Method
1. Ask a question
2. Propose a hypothesis
3. Make a prediction(s)
4. Test the prediction(s)
5. Draw Conclusions
Evolution by Natural Selection
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differential survival and reproduction of
organisms in a population with different
phenotypes resulting from interactions of
the organism and its environment.
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Phenotype - physical, chemical, or behavioral
traits of an organism.
Genotype - genetic make-up
Premises of Natural Selection
1. Individuals in a population vary, however slightly
2. These variations can be inherited
3. Generally, members of a population produce more
offspring than the environment can support
4. Individuals whose inherited characteristics fit them best
to the environment are more likely to survive and leave
more offspring
5. Over time, the favorable variations tend to accumulate
in a population