Introduction to Biology Course Overview Adapted from Cheryl Massengale at biologyjunction.com and class notes

Introduction Biology is the study of life. Life began around 3.8 billion years ago. First organisms were single celled. Organisms eventually began to change over time, or evolve. Today there are millions of species that inhabit almost every region of Earth.

Themes of Biology Scientific Inquiry Ecology and Interdependence of Organisms Evolution and Classification Biochemistry Cell Structure and Function Reproduction and Inheritance

Scientific Inquiry Scientists carefully follow safety rules in the laboratory. Scientists use specialized equipment to complete experiments. Scientists use the scientific method to figure out the answers to problems. The scientific method is a step-by-step model used to identify and test various problems and scenarios.

The Scientific Method Step 1 – Make an Observation – Employ your 5 senses to perceive objects or events. Step 2 – Form a Hypothesis – Ask a question based on your observations. – Form a testable statement – Often written as an “if-then” statement Step 3 – Perform an Experiment – Write a procedure to test the hypothesis – Must have an independent variable (what’s manipulated) and a dependent variable (what’s measured) – Controls are extremely important

The Scientific Method Step 4 – Organize and Analyze Data – Place measurements in graphs, charts, tables, or maps – Perform any calculations necessary – Determine what the data is telling you Step 5 – Form a Conclusion – Drawn from the data collected during an experiment – May support or reject the hypothesis Step 6 – Report Results – Publish findings in peer-reviewed journals – Must be unbiased – Subject to examination and verification by other scientists – Allows scientists to build on the work of others

Microscopes Most important tool in biology Produces an enlarged image of an object Increase in apparent size is called magnification The ability to show details clearly is called resolution

Microscopes Compound Light Microscope – Used to study live specimens – Can see in color – Uses two lenses: an ocular and objective lens – Magnification is determined by multiplying the powers of both lenses – Relatively inexpensive Electron Microscope – Used to study still (non- living) specimens – Black and white only – Uses a beam of electrons to magnify specimens – 200,000X magnification – Very expensive

Measurements

Ecology The interaction of organisms with one another and with their environment is ecology. Organisms depend on biotic and abiotic factors in their environment to survive. All organisms need nutrients, water, and gases from the environment.

Evolution and Classification Populations of organisms change over time Investigates how different organisms came into existence, how modern organisms are related to past organisms, why organisms look and behave a certain way, how groups of organisms are related Natural selection is the driving force of evolution and is based on the phrase “survival of the fittest.”

Biochemistry Living things are highly organized and require a constant supply of energy to maintain their orderly state. All energy comes from the sun, whether directly or indirectly. There are 4 macromolecules essential for life: – Proteins – Carbohydrates – Lipids – Nucleic Acids

Biochemistry Water is the universal solvent. pH refers to how acidic or basic a substance is. ATP is the energy currency for cells. Photosynthesis is the process by which some organisms (plants and some bacteria) use the energy from the sun to make glucose. Cellular respiration is the process by which glucose is broken down to produce energy for the cell.

Biochemistry 3 parts of an atom: – Proton – Neutron – Electron Covalent bonding – shares electrons between atoms Ionic bonding – transfers electrons between atoms Hydrogen bonding – forms between hydrogen atoms of one molecule and O, N, or F of another molecule

Cell Structure and Function Cell is the basic unit of life. All organisms are made of and develop from cells. 3 parts of a cell: – Cell membrane – Cytoplasm – Nucleus

Cell Structure and Function Two types of cells: – Eukaryotic – prokaryotic Eukaryotic cells have a nucleus, but prokaryotic cells do not have a nucleus. Eukaryotic cells have organelles that have specialized functions.

Levels of Organization

Reproduction and Inheritance All organisms produce new organisms like themselves. Organisms transmit hereditary information to their offspring. The genetic information in cells is stored in DNA. DNA contains the instructions for traits and to make all the cell’s proteins.

Characteristics of Life Organization Reproduction Growth Homeostasis Energy use Response Adaptation and Evolution Genetic code

Organization Orderly structure Atoms  molecules  cells  tissues  organs  organ systems Made of one or more cells Each cell has the genetic code (DNA/RNA) All parts function together

Reproduction The production of offspring Not essential for survival of the individual, but essential for the species as a whole Species – group of organisms that can interbreed and produce fertile offspring

Growth An increase in the amount of living material and the formation of new structures Development – all of the changes that take place during an organism’s life

Homeostasis Regulation of an organism’s internal environment to maintain conditions suitable for its survival BALANCE – Ex. Temperature Requires use and taking of energy

Response A reaction to a stimulus in the environment Environment – the surroundings Stimulus – any condition in the environment that requires an organism to adjust Ex – You touch a hot stove eye. The stimulus is the heat. The response is you pulling your hand away.

Adaptation and Evolution Adaptation – any structure, behavior, or internal process that enables an organism to respond to stimuli and better survive – Inherited from previous generations Evolution – the gradual accumulation of adaptations over time