Introduction: Themes in the Study of Life Chapter 1

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 Order Regulation Energy Processing Homeostasis (balance within limits) Energy Processing Evolutionary Adaptation Response to Environment Reproduction Inheritance of genetic material (DNA) 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?

Themes of biology

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

Organisms Interact with Other Organisms and Their Environment

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 Bacteria Lack internal membranes Protozoa, Fungi, Plants, Animals Possess 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

Feedback Mechanisms Regulate Biological Systems NEGATIVE FEEDBACK POSITIVE FEEDBACK

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.

The Core Theme of Biology Evolution

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

Unity in the Diversity of Life

Charles Darwin and the Theory of Natural Selection On the Origin of Species by Means of Natural Selection (1859) Contemporary species arose from a succession of ancestors “Decent with modification” 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

The Tree of Life

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?