Biology
• The scientific study of life– Scientists use the Scientific Method to answer
questions posed by the living world
• Much of biology focuses on how organisms have adapted to life in myriad environs on our planet– Evolution is the central theme of biology– Mother-of-Pearl Plant (Graptopetalum paraguayense)
is adapted to life with limited water
Properties of Life
1. Order2. Regulation
– Homeostasis (balance within limits)
3. Energy Processing4. Evolutionary Adaptation5. Response to Environment6. Reproduction
– Inheritance of genetic material (DNA)
7. Growth and Development– Regulated by DNA
Check Your Understanding
• What is the scientific method and what is its role in biology?
• Why is evolution considered to be the unifying, central theme of biology?
• Discuss the seven major properties associated with all living things?
New Properties Emerge at Each Level in the Biological Hierarchy
• Levels of Organization– See figure on the left
• Emergent Properties– New functions that develop
as complexity increases– Not present in level below
• Reductionism studies complex systems by looking at smaller, more manageable parts
• Systems Biology models the interactions within system based on knowledge of individual parts
Life Requires Energy Transfer and Transformation
• Photosynthesis– Light (Kinetic Energy) and
CO2 to organic molecules (Chemical Energy)
– Producers
• Respiration– Organic molecules to CO2
and new chemical energy– Consumers
Structure and Function are Correlated at All Levels of Biological Organization
Form Fits Function (and vice versa)
The Cell is the Basic Structural and Functional Unit of Life
PROKARYOTE EUKARYOTE
BacteriaLack internal membranes
Protozoa, Fungi, Plants, AnimalsPossess internal membranes
The Continuity of Life is Based on the Heritable Information Found in DNA
• Replication– DNA creates new DNA– Genome is term for all the
genetic material in a single cell
• Protein Synthesis– Transcription
• DNA creates RNA
– Translation• RNA creates proteins
Check Your Understanding• Describe how each level within the hierarchy of life is related to the level
below it and the level above it. Define emergent properties of life and how this relates to the hierarchy. Differentiate between reductionism and systems biology.
• Differentiate between photosynthesis and cellular respiration. Between producers and consumers. How do these terms relate to the energy transformations of life?
• Describe the relationship between form and function using a bird’s wing bones as an example.
• Differentiate between a prokaryotic and a eukaryotic cell.• Differentiate between DNA replication, DNA transcription, and RNA
translation.• Differentiate between positive and negative feedback mechanisms.
Provide one example of each type of mechanism.
Classifying the Diversity of Life
• Taxonomy is the science of classifying organisms– Domains are the most
encompassing levels– Species is the most specific
designation
• Binomial System of Nomeclature– Genus species
Three Domains of Life
• Bacteria (prokaryotes)• Archaea (prokaryotes)• Eukarya (eukaryotes)– Plantae– Fungi– Animalia– Protista
Charles Darwin and the Theory of Natural Selection
• On the Origin of Species by Means of Natural Selection (1859)1. Contemporary species arose from a succession of
ancestors• “Decent with modification”
2. Decent with modification is caused by “natural selection”• Individuals vary within a population based on heritable traits• Populations produce far more offspring than can possibly
survive which leads to competition• Species are suited (adapted) to their environment provided
the environment does not change
Check Your Understanding
• Differentiate between a domain and a species. How are species universally identified when their names are written or typed?
• Differentiate between the organisms belonging to the domains Bacteria, Archaea, and Eukarya.
• How does a cilia in a paramecium and on cell lining the respiratory tract of a human illustrate the process of evolution?
• What work by Charles Darwin changed the face of biology forever? What three things did Darwin say were necessary for decent with modification to occur?