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

We’re Here to Train Your Brain! Complex ideas involve connections between many neurons Learning difficult concepts causes new neurons to form Learning builds and maintains healthy neurons One of your healthy and well-connected neurons after Bio 21!

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

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

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

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

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.

 Living things maintain homeostasis = a relatively stable internal condition regulation and homeostasis response to environmental changes

Plant Responses to Sunlight Alfalfa leaves oriented toward sunlight to maximize photosynthesis Desert plant leaves oriented vertically to minimize water loss 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

How Do Biologists Study Living Things? Biology 21 Definition An Hypothesis will haveAn 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 hypothesesTesting hypotheses –Controlled Experiment test designed to determine the effect of one factor while keeping all other factors constanttest 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 studiedexperimental = sample treated to test for effect of the factor being studied control = sample treated like experimental in all ways EXCEPT for the factor being studiedcontrol = 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

How Do Biologists Study Living Things? Supported Hypotheses Supported Hypotheses Theory = broad explanation of a natural phenomenon that has been supported by a large body of evidenceTheory = 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 timePrinciple 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.All living things are composed of cells and cell products; all cells come from pre-existing cells. –Principle of Evolution –Principle of Emergent Properties