Chapter 1 Introduction to Biology

Chapter 1Introduction to BiologyLESSON 1: UNIFYING PRINCIPLES OF BIOLOGYLesson Objectives

State the four unifying principles of biology as defined by the College Board.Briefly explain how biological life on Earth evolves.Explain the purposes of free energy processes and homeostasis in biological organisms.Describe the theories and dogma of biological information.Describe how living things interact and the levels of structural, biological, and ecological organization in biological systems.

The Big IdeasEvolutionevolution drives the diversity and unity of lifeFree Energybiological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasisInformationliving systems store, retrieve, transmit, and respond to information essential to life processesSystemsbiological systems interact, and these systems and their interactions possess complex propertieshttp://youtu.be/ibhnP5suqK8 (9:09)

EvolutionEvolutionevolution drives the diversity and unity of lifeWhat is diversity?DiversityDo all species on Earth live in the same type of habitatDo we all reproduce alikeDo we are physically resemble one anotherDo we all have the exact same resource needsEvolution drives the diversity of life which insures survival through variations that develop through genetic mutations that are transferred between or within populations of species by means of non-random mating, and immigration and emigration of individuals within and from populations.

EvolutioncontinuedWhat is the unity of life?

What do we mean by unity of life? universal usage of DNA to store genetic informationthe ribosome technique of protein synthesisproteins serve as enzymes and catalyststhe same 20 amino acids are always useda universal genetic codeDNA triplets coding for same amino acidthe use of proteins and lipids to make membranesthe use of the ATP-ADP cycle for chemical energyFree EnergyFree Energybiological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis

Free energy originates from photons taken in by plants and then is transferred, each organism that it is transferred to uses it for their life processes. TOP PICTUREATP energy storage humans, made during CR goes through continuous reactions to release and restore 6Homeostasis

So what drives homeostasisNegative Feedback Loop: Receptors in body detect when something is off balance, info goes to control center (in humans, brain), an effector gets turned on and causes a reaction to restore balance There are also positive feedback loops but these produce physiological responses that reinforce initial changes in a controlled condition. Examples: childbirth, ovulation, blood clotting (all changes to normally controlled conditions, these have to be shut off by some event outside a system.7InformationInformationliving systems store, retrieve, transmit, and respond to information essential to life processes

SystemsSystemsbiological systems interact, and these systems and their interactions possess complex propertiesDescribe how living things interact and the levels of structural, biological, and ecological organization in biological systems.

Competition for habitat/territory; for mates; for foodClown fish commensalism, 1 benefits other unharmedBee mutualism, both benefitMosquito parasitism, 1 benefits, other harmed9Lesson Summary

Four underlying principles form the basis of biology. They are evolution, free energy, information, and systems.The great diversity of life on Earth today is the result of 4 billion years of evolution. During that time, living things evolved from simple, single-celled organisms to complex, multicellular life forms.Biological systems utilize free energy & molecular building blocks to grow, to reproduce and tomaintain dynamic homeostasis.Living systems store, retrieve, transmit & respond to information essential to life processes.Many living things interact with one another in some way. The interactions are often necessary for their survival.

LESSON 2: DISCOVERY OF CELLS AND MICROSCOPES

Lesson Objectives

State the cell theory, and list the discoveries that led to it.Be able to identify the parts of a compound light microscope.Explain the differences between a SEM (Scanning Electron Microscope) and a TEM (Transmission Electron Microscope).

Abiogenesis or Biogenesis?

Recipe for BeesKill a bull during the first thaw of winterBuild a shed.Place the dead bull on branches and herbs inside the shed.Wait for summer. The decaying body of the bull will produce bees.

12Recipe for Bees: written by a Roman poet about 2000 years agoAristotle300 B.C. (2300 years ago)

Living things follow a set of natural rules different from nonliving things

Special vital forces (magical forces in the air) brought living things into being from nonliving thingsA hypothesis known as : spontaneous generation also called abiogenesis

13Vital forces in air..About 350 years ago Challenges began to arise to the beliefs of Aristotle

How did they challenge these ideasThrough experiments and observations to answer the questions about life..Do living things come from nonliving things?????

OBSERVATIONSDiscovery of CellsCell: smallest unit that can carry out the processes of life; including transport of materials, obtaining and using energy, waste disposal, replication, and responding to their environment.If you look at living organisms under a microscope you will see they are made up of cells; which are the basic unit of all living things

15Anton von Leeuwenhoek mid 1600s

Dutch businessman credited for creating 1st microscope;Magnification 200X Opened up new worldChanged ideas about disease & sterilization for the next 200 years!!

ANIMALCULES

16Leeuwenhoek was a glass maker by trade, his microscope had a single lenspoint out microscope in pictureSaw tiny living organisms in droplets of water; no one had ever seen this beforeLeeuwenhoek was also very curious, and he took great care in writing detailed reports of what he saw under his microscope. He was the first person to report observations of many microscopic organisms. He discovered blood cells and was the first person to see living sperm cells. In 1683, Leeuwenhoek wrote to the Royal Society of London about his observations on the plaque between his own teeth,a little white matter, which is as thick as if twere batter. He called the creatures he saw in the plaque animacules He called his discoveriesCLICK (animalcules), or tiny animals. This report was among the first observations on living bacteria ever recorded.

Robert Hooke late 1600s (1663)

English physicist; used one of 1st light microscopes.Coined the term cell after observing cork cells

17Tell about his drinking; time in cells; acquisition of hook nose(CLICK>>>OPEN YOUTH PIC); Do not tell STD HERE!!!!Hookes drawing of cork cells; while examining thin slices of cork under his microscope noticed what looked like many small chambers. Hooke called the chambers cells b/c they reminded him of a monasterys tiny rooms known as cellsHooke calculated about 1200 million cells were in one cubic inch.

In 1665 Hooke published a book Micrographia, in which he wrote:... I could exceedingly plainly perceive it to be all perforated and porous, much like a Honeycomb, but that the pores of it were not regular.... these pores, or cells, ... were indeed the firstmicroscopical pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this...

EXPERIMENTSFrancesco RediItalian Physician1668Studied maggotsDid not believe they came from decaying meatSet up an experiment

Redis Experiment

Controlled variableManipulated variableResponding variabledependent variable variable in a scientific experiment that is affected by another variable, called theindependent variable=>responding variableindependent variablevariable in a scientific experiment that is manipulated by the researcher to investigateits affect on another variable, called the dependent variable=>manipulated variableControls=>controlled variable

19Success???Redi thought so, butNo air could get into the experimental jarsThere was no vital forcePeople still believed in spontaneous generation or abiogenesis

Back to the drawing board

Redis Second Experiment

Control Group

Experimental GroupNew experiment, mesh air in but holes too small for flies to get in21ConclusionMaggots do not come from dead meat. Hypothesis has been supported!

Does this disprove abiogenesis?Only for flies!

The Debate Continued.Was Redi right, Aristotles ideas had survived for a millennia, how could they be WRONG!!!!Lets follow the history of the scientific investigation and further observations that finally solved the riddleJohn Needham (British Biologist & Roman Catholic priest

Mid-1700s Believed in abiogenesis for microscopic organisms

Needhams Experiment

Broth in flask boiled to sterilize itKilling microorganisms, then sealed

Microorganisms found growing in flask!!!!

Declared life from nonlifeProblem???had not heated it enough to kill all..24Lazzaro Spallanzani (Italian Scholar)1768Did not believe in spontaneous generationRead about Needhams workSamples had not been heated enough

Broth in two flasks boiled to sterilizeSealed one immediately after boilingLeft other open

Bacteria found growing only in open flask

Actual he sealed out air and no life , let air in life.does this support spontaneous generation25More Observations1839Schleiden and Schwann made an important discovery about living things Beliefs are about to change..

Matthias Schleiden 1839

German botanistAll plants are made of cells.27What does a botanist study again? PLANTS AND PLANT LIFE NAME SCHLEIDEN>>>LEILower left onion skin cellscan use distinguish between the cell wall and cell membrane? YES Where is the nucleus? Purple circles

Lower right plant cellwhat are those green oval-like structures called? Chlorophyll (chloroplasts)Can you see the cell wall and cell membrane? Yes but not as wellTheodor Schwann 1839

German scientistAll animals are made of cells

Further concluded all plants and animals are made of cells28Schwann was a scientists who studied mainly animalsNAME SCHWANN>>>SWANNLower leftanimal skin cells (colorized)Lower rightalso colorized; what is the blue structure? NUCLEUS The red structures? CELL MEMBRANEThe green structures are the cytoskeleton composed of microtubulesMore Observations1839BUT.Schleiden and Schwann did not understand where cells came from. Was the belief of the time dating back to the time of Aristotle (300 B.C.) right? Did cells come from nonliving matter (Abiogenesis).

Rudolf virchow 1855

German physician

Still one more experiment before true understandingWhere a cell exists,there must have beenA preexisting cell

30What is a physician? MEDICAL DOCTORVirchow specialty was the study of cell reproduction; he studied it for many years before making his conclusionsWhere a cell

Does Abiogenesis happen?A contest was devised by the French Academy of Sciences with a cash award for the person who could disprove abiogenesis.

Louis PasteurFrench ScientistMid- 1800sKnew he needed to let air in, but not dustWas inspired by

Swan Necked FlaskPour broth into flaskHeat neck & shapeBoil brothWait!

Pasteurs Experiment

34Conclusion--1859Since no microorganisms could get into the broth (they were trapped in the curve of the swan neck), none grew.

Pasteur broke the neck off a year later, allowed it to be exposed to air & microorganisms began to quickly grow.

BiogenesisLiving things do NOT come from non-living things. Spontaneous generation does NOT occur, even with very small organisms.Living things only come from other living things!

Cell Theorywidely accepted explanation of the relationship between cells and living thingsAll organisms are made up of one or more cells.All the life functions of an organism occur within cells.All cells come from preexisting cells.

37CLICK