BSC 2010

Chapter 1

Defining Biology

• Science of living organisms

• Science-From Greek “to know”– Body of knowledge– Method of inquiry

Characteristics of Science

• Deals with falsifiable concepts

• Dynamic body of knowledge

• Open minded approach

Defining Feature of Life• Composed of a cell or

cells (Cell theory)• Sense and respond • Reproduce• Grow and develop• Cycle energy• Regulate- homeostasis• Display order• Contain DNA as

hereditary material

Connections- Themes within Biology

• Evolution– Change in a

population over time

– Natural selection– Selects for pre-

existing traits• Unity• Diversity

Themes in Biology

• Emergent Properties– Novel properties– Appear as higher

levels of complexity are attained

– Due to arrangement and interaction of parts

– Not unique to life

Themes in Biology

• Correlation between structure and function

• Seen at all levels of organization from atoms to biosphere

Themes in Biology

• The cell as the basic unit of life both structurally and functionally

• All cells share common characteristics

Themes in Biology• Continuity based on

DNA as heritable information

• All cells contain DNA• DNA encodes all

proteins found within an organism

• DNA allows those codes to be passed on to progeny

Themes in Biology

• Homeostasis• Maintenance of

conditions within tolerable range

• Feedback regulation– Negative– Positive

Negative Feedback

Positive Feedback

Reductionism and Systematics

• Reductionism– Take apart to

understand• Systematics

– Study interactions to understand

– Determine evolutionary relationships

– Ecosystem dynamics

Levels of Biological Organization

• Atom• Molecule• Organelle• Cell• Tissue• Organ• Organ system• Organism

Levels of Organization

• Population• Community• Ecosystem• Biosphere• ? Universe?

Classification of living Organisms

• Domain• Kingdom • Phylum• Class• Order• Family• Genus• Specie• Binomial Nomenclature• Systematics leading to

entirely different schemes

Bacteria

Archae

Eukarya

Main Types of Scientific Inquiry• Hypothesis based• Scientific method• Observation• Question• Hypothesis• Prediction• Experiment• Conclusion

• Discovery based• Observations- Use

senses to intake data• Field studies• Information gathering

without drawing conclusions

• Conclusions drawn from observations without experimentation

Types of Reasoning

• Inductive– Derive generalizations

from a number of specific observations

– Common in Discovery science

• Deductive– Draw specific

conclusions based on generalizations

Summary• Evolution is the over arching concept in biology• New properties emerge at each level in the biological

hierarchy• Organisms interact with their environment exchanging

matter and energy• Structure and function are correlated at all levels.• Cells are the basic functional and structural unit of life• Continuity of life is based on heritable information

contained within DNA• Feedback mechanisms regulate biological systems