Ch 1 Course Overview

Themes in the Study of BiologyCh 1.1 Course OverviewI. Biology is the scientific study of lifeA. Life is recognized by what living things do.B. All living things demonstrate the following characteristics:1. Order2. Adaptation3. Response to the environment4. Reproduction5. Growth & Development6. Energy processing7. Regulation (Homeostasis)

Characteristics of life

II. Themes connect the concepts of Biology (sec 1.1)We use themes to organize and connect biological information.The overarching theme used today is biological evolution1. Evolution is used to connect what we know about living and extinct organisms.2. Living organisms are modified descendants of common ancestors.So, we look for common traits, chemistry, etc. to help us see how one area of info. relates to another or one organism is related to another.Themes (cont.)B. Emergent properties New properties emerge at each level in the biological hierarchy.1. The study of life is divided into different levels of biological organization. These levels area. Atomsj. Populationsb. Moleculesk. Communitiesc. Organellesl. Ecosystemsd. Cells(m. Biomes)f. Tissuesn. Biosphereg. Organsh. Organ systemsi. Organisms

Emergent properties and Reductionism2. Emergent properties result from the arrangement and interaction of the parts within a system.a. Emergent properties are seen innon-biologicial systems too.b. Reductionism- the study of a systemby reducing it to smaller, more manageable parts (i.e. study thecomponents of a system)We must balance reductionism with emergent properties to get the big picture

Emergent properties and Systems Biologyc. Systems Biology- studies how the component parts of a system work together by making modelsAn example would be to look at the parts of a DNA molecule to see how it is constructed, then to study how the construction of DNA makes it easier to use and to copy DNA. (Form follows Function)Themes (cont.)Organisms interact with the environment & exchange matter and energy with it.1. Organisms react with both biotic & abiotic factors in the environment.2. Both the organism and the environment will be affected.3. Ecosystem dynamics (how one part of an ecosystem affects another) include: a. the cycling of nutrients- plants take nutrients from the ecosystem that eventually return to it. b. Energy flow through the ecosystem- energy flows from sunlight to producers to consumers

Energy flow in ecosystems:1) All organisms do work. Work requires energy.2) Energy is stored in many forms.3) Energy exchanges between organisms & the environment require energy transformations.4) Energy flows through an environment entering as light & exiting as heat (usually) having taken many different forms.Themes (cont.)Structure & function are closely related at all levels of biology.1. Form fits function at all levels of biologya. Ex. Gulls wings are curved to provide lift.b. Ex. Mitochondrias folded inner membranes provide more surface area so more reactions occur.

Themes (cont.)Cells are the basic unit of structure & function in an organism.1. The cell is the lowest level of organization that can carry out the functions of life.2. All cells are enclosed by a membrane and use DNA to hold (encode) their genetic info.3. Because cells can divide, they can carry out growth, development, and the repair of multicellular organisms.4. Two types of cells:1)Eukaryotic- has membrane wrapped organellesincluding the nucleus.2) Prokaryotic- no organelles & thus no nucleusCell typesEukaryotic Animal CellProkaryotic bacterial cell

Themes (cont.)E. The continuity of life is based on inheritable (heritable) information found in DNA1. DNA is a double stranded molecule made of 4 different kinds of nucleotides.a. A nucleotide is made of sugar, phosphate and one of four different nitrogen basesb. Nucleotides are joined together in long strands. c. Two of these strands, linked to each other by hydrogen bonds and twisted into a spiral make a DNA molecule.2. One long, double stranded DNA molecule makes a chromosome.DNA Molecule & Genes

DNA153. Genes are sections of just 1 strand of a chromosome4. So- Genes are made of DNA and 2 long chains of Genes, plus some extra DNA, make a chromosome.5. Genes are units of inheritance; genes carry the genetic info. from parents to kids.6. Gene expression- making a protein using the instructions found in the DNA of the gene.7. Proteins give us our traits.8. Genes are expressed indirectly through a two step process using RNA .9. Genes control development & maintenance of organisms10. A genome is the whole genes set of an organism.Inheritance

Themes (cont.)F. Regulation of biological systems is through feedback mechanisms 1. Feedback systems let organisms self-regulate their processes.2. Negative feedback occurs when the product of a process builds up and forces the system that makes it to slow down or stop making the product. (ex. 3. Positive feedback occurs when the build up of the product causes the system that makes it to speed up making the product.

Feedback mechanismsNegative feedback Positive feedback

Review Questions1. What are the 7 characteristics of life?2. Give an example of each.3. Name all 7 themes used to connect the concepts of Biology.4. Briefly define each theme.

Acknowledgements: This presentation is drawn almost entirely from the materials provided by Reese Campbell 8th ed. DVD materials & notes.