Introduction to Biology Studying Life’s Diversity and Intricate Processes

Biological Inquiry Bio = of living things Biological Science: observation, identification, experimental investigation and theoretical explanation of natural phenomena What are the Characteristics of Living Things? What are Fundamental Concepts that Relate to these Characteristics? How Do Biologists Study Living Things?

What are common characteristics of living things? Properties of Life organization involving cells energy use and metabolism response to environmental changes regulation and homeostasis growth and development reproduction biological evolution

Concept: New Properties Emerge at Each Level in the Biological Hierarchy Principle of Emergent Properties New characteristics arise out of the arrangement and interactions of the components of a complex system (whole > sum of the parts) organization

Organizational Hierarchy of Life Most Complex Least Complex biosphere inhabitable regions of earth ecosystem coral reef (living + nonliving) community coral reef populations population school of fish organism fish organ system nervous system organ brain tissue nervous tissue cell neuron organelle nucleus macromolecule DNA molecule nucleotide atom nitrogen sub-atomic particles protons, neutrons, electrons

Concept: Cells are an Organism’s Basic Units of Structure and Function. Two types of cells Prokaryotic Archaea and Bacteria few internal membranes no membrane-bound nucleus Eukaryotic Protists, Fungi, Animals, Plants extensive internal membranes membrane-bound nucleus organization

Concept: Structure and Function are Correlated at all Levels of Biological Organization. How is red blood cell structure suited to its function of carrying oxygen? organization

Energy Use and Metabolism Energy = ability to do work Energy conversion = change of one form of energy to another Metabolism = sum of chemical reactions in an organism Heterotrophic: other feeder taking in organic molecules produced by other organisms Autotrophic: self-feeder photosynthesis = using the energy of the sun to produce organic molecules

reproduction regulation Concept: The Continuity of Life is Based on Heritable Information in DNA. The molecule of heredity = DNA = deoxyribonucleic acid reproduction regulation

Genomes and Proteomes reveal evolutionary relationships Per 23 chromosomes Now estimated at 30,000 genes Proteome: all proteins produced in a cell or organism Genome: complete genetic composition of an organism Genomes and Proteomes reveal evolutionary relationships

Nuclear division retaining the original chromosome number Concept: The Continuity of Life is Based on Heritable Information in DNA. Nuclear division retaining the original chromosome number Nuclear division reducing the chromosome number, leading to sperm or eggs

growth and development Concept: The Continuity of Life is Based on Heritable Information in DNA. Growth = increase in size Development = change in characteristics growth and development

Concept: Feedback mechanisms regulate biological systems.

Concept: Feedback mechanisms regulate biological systems. Living things maintain homeostasis = a relatively stable internal condition regulation and homeostasis response to environmental changes

Plant Responses to Sunlight Desert plant leaves oriented vertically to minimize water loss Alfalfa leaves oriented toward sunlight to maximize photosynthesis http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropisms.html http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropisms.html response to environmental changes

Concept: Evolution Accounts for the Unity and Diversity of Life Two mechanisms of evolutionary change Vertical Descent with Mutation: through changes in DNA, new species arise from pre-existing species Natural Selection: individuals with traits that provide an advantage in the current environment are more likely to survive and reproduce response to environmental changes biological evolution

Concept: Evolution Accounts for the Unity and Diversity of Life Vertical Descent with Mutation

Concept: Evolution Accounts for the Unity and Diversity of Life Natural Selection leads to a change in the genetic characteristics of a population  evolution Adaptation = characteristic that promotes survival and reproduction

The Unity and Diversity of Living Things An Evolutionary Tree of Life The Three Domains of Life Represent the Earliest Branches in Evolutionary History Contains multiple kingdoms

How Do Biologists Study Living Things? Discovery Science Collect Data without a pre-stated hypothesis Make Observations = objective notations of a phenomenon Can lead to formulation of hypotheses Example: determine how many amphibian species are present in a specific environment

How Do Biologists Study Living Things? Hypothesis-based Science Ask Questions or make Observations Formulate an Hypothesis: tentative answer to well-framed question Make Predictions based on hypothesis Test Predictions by Conducting Experiments Analyze experimental data Determine whether data supports hypothesis You Tube video on Paramecium contractile vacuole

How Do Biologists Study Living Things? Biology 21 Definition An Hypothesis will have Two measurable variables Precise relationship between them (relationship = prediction) The relationship between DNA content and length of the cell cycle is a direct proportion.

How Do Biologists Study Living Things? A good hypothesis is Testable experiments can be designed to test predictions from the hypothesis experimental results must be repeatable Falsifiable allows scientists to eliminate alternative hypotheses

How Do Biologists Study Living Things? Testing hypotheses Controlled Experiment test designed to determine the effect of one factor while keeping all other factors constant experimental = sample treated to test for effect of the factor being studied control = sample treated like experimental in all ways EXCEPT for the factor being studied

Use of a Controlled Experiment Increasing dose of almonds on subjects with hyperlipidemia. Full almond = 73 grams/day Control = whole wheat muffins (>5% saturated fat) Half almond = half dose almond + half dose muffins All supplements provided equal amounts of energy in the diet. Jenkins, et al., 2002, Circulation 106:1327 http://circ.ahajournals.org/cgi/content/full/106/11/1327 (Circulation. 2002;106:1327.) Dose Response of Almonds on Coronary Heart Disease Risk Factors: Blood Lipids, Oxidized Low-Density Lipoproteins, Lipoprotein(a), Homocysteine, and Pulmonary Nitric Oxide A Randomized, Controlled, Crossover Trial David J.A. Jenkins, MD; Cyril W.C. Kendall, PhD; Augustine Marchie, BSc; Tina L. Parker, RD; Philip W. Connelly, PhD; Wei Qian, PhD; James S. Haight, MD; Dorothea Faulkner, RD; Edward Vidgen, BSc; Karen G. Lapsley, DSc; Gene A. Spiller, PhD Background— Although recent studies have indicated that nut consumption may improve levels of blood lipids, nuts are not generally recommended as snacks for hyperlipidemic subjects because of their high fat content. Furthermore, the effective dose is still unknown. Methods and Results— The dose-response effects of whole almonds, taken as snacks, were compared with low-saturated fat (<5% energy) whole-wheat muffins (control) in the therapeutic diets of hyperlipidemic subjects. In a randomized crossover study, 27 hyperlipidemic men and women consumed 3 isoenergetic (mean 423 kcal/d) supplements each for 1 month. Supplements provided 22.2% of energy and consisted of full-dose almonds (73±3 g/d), half-dose almonds plus half-dose muffins, and full-dose muffins. Fasting blood, expired air, blood pressure, and body weight measurements were obtained at weeks 0, 2, and 4. Mean body weights differed <300 g between treatments. The full-dose almonds produced the greatest reduction in levels of blood lipids. Significant reductions from baseline were seen on both half- and full-dose almonds for LDL cholesterol (4.4±1.7%, P=0.018, and 9.4±1.9%, P<0.001, respectively) and LDL:HDL cholesterol (7.8±2.2%, P=0.001, and 12.0±2.1%, P<0.001, respectively) and on full-dose almonds alone for lipoprotein(a) (7.8±3.5%, P=0.034) and oxidized LDL concentrations (14.0±3.8%, P<0.001), with no significant reductions on the control diet. No difference was seen in pulmonary nitric oxide between treatments. Conclusions— Almonds used as snacks in the diets of hyperlipidemic subjects significantly reduce coronary heart disease risk factors, probably in part because of the nonfat (protein and fiber) and monounsaturated fatty acid components of the nut.

How Do Biologists Study Living Things? Supported Hypotheses Theory = broad explanation of a natural phenomenon that has been supported by a large body of evidence Principle or Law = theory that has been supported over a long period of time Cell Principle All living things are composed of cells and cell products; all cells come from pre-existing cells. Principle of Evolution Principle of Emergent Properties