Chapters 1 - 3

Biology Basics

Scientific Method

and Chemistry

Biology is a science

• Science– c.1300, "knowledge (of something) acquired by study," also "a

particular branch of knowledge," from O.Fr. science, from L. scientia "knowledge," from sciens (gen. scientis), scire "to know," probably originally "to separate one thing from another, to distinguish,"

– Modern sense of "non-arts studies" is attested from 1678. – Main modern (restricted) sense of "body of regular or methodical

observations or propositions ... concerning any subject or speculation" is attested from 1725; in 17c.-18c.

• Harper On-line Etymology Dictionary**One of my FAVORITE resources for better understanding of terms**

• Since biology a science, it is about knowledge based on methodical observation

• Biologists attempt to exclude subjective measures such as opinion and emotion from their studies

• Pseudoscience– is defined as a body of knowledge,

methodology, belief, or practice that is claimed to be scientific or made to appear scientific, but does not adhere to the scientific method, lacks supporting evidence or plausibility,or otherwise lacks scientific status.

• How to identify pseudoscience– Use of vague, exaggerated or untestable

claims– Over-reliance on confirmation rather than

refutation– Lack of openness to testing by other experts– Lack of progress– Personalization of issues– Use of misleading language

Examples of PseudoscienceSee Web Task – Week 1

– Apollo moon landing hoax accusations – Astrology – Creation science – Crop circles – Crystal healing – Dianetics – Dogon people and Sirius B – Face on Mars– Homeopathy – Lunar effect – Paranormal subjects

• Channeling, Dowsing, Electronic voice phenomenon , Extra-sensory perception, Levitation, Materialization Psychic surgery Séances Psychokinesis

– Therapeutic touch – Perpetual motion – Quantum mysticism – Ufology – The Bermuda Triangle – Pseudoarchaeology – Animal mutilations – Tutankhamun's curse – Tunguska event

– Graphology – Phrenology – Primal therapy – Subliminal perception – Anthroposophic medicine, – Applied kinesiology – Attachment therapy – Bates method for better eyesight – Biorhythms – Brain Gym – Electromagnetic Hypersensitivity (EHS) – Faith healing – Hypnosis – Iridology – Magnetic therapy – Maharishi's Ayurveda. – Radionics – Scientific racism – Traditional Chinese Medicine. – Shroud of Turin – Hongcheng Magic Liquid – Laundry balls – Stock market prediction

Biology is the study of life

• So, what does it mean to be “alive”– Our next discussion will be the properties of

living things

• What things are living?– Bacteria, amoebas, algae, fungi, plants,

corals, sponges (in the ocean), animals, viruses (maybe)

Properties of Living Things

• Life is surprisingly difficult to define– Many characteristics of life also exist in some nonliving things– Wind can “move under its own power”– Crystals and fire can “grow”– Water “responds to its environment”

• Ludwig von Bertalanffy’s cell “experiment”– If I take a living cell and blend it in a blender, it is no longer alive– However, chemically nothing has been added or deleted

• All the chemicals are the same, but the cell is no longer alive.– Life is not the components but the organization of the

components– A system where the whole is greater than the sum of the parts– Life is an emergent property whose behaviors cannot be

predicted solely from the lower level components that make it up

1: Organization

• Living things are separated from their environment by a lipid (fat) based membrane– Living things are cells, or are made of cells– Therefore in the list below, the smallest level that is truly living is

the cellular level

• Living things show organization– Organization Hierarchy of living things

• Atoms, Molecules, Macromolecules, Organelles, Cells, Tissues, Organs, Organ Systems, Organisms, Populations, Communities, Ecosystems, Biomes, Biospheres

• Organization is partly about division of labor which provides efficiency and allows organisms to grown larger than would otherwise be possible

2: Acquire & metabolize nutrients and assimilate & use energy

– Nutrients• Oxygen and other gases

– Depends on the organism***• Carbohydrates• Lipids

– Some of which are known as fats• Proteins• Nucleic Acids• Vitamins & Minerals• Water

– The most commonly omitted nutrient– Metabolism has 2 parts

• Anabolism – building of molecules from component parts• Catabolism – breaking down molecules into their components• Organisms catabolize nutrients to get the building blocks for

anabolism of substances they need

3: Irritable - Respond to stimuli and the environment

• Organisms move toward water, food and shelter

• Organisms move away from dangerous conditions such as predators and environmental hazards (heat, cold, chemicals, sun)

• Organisms react to changes in their environments

4: Maintain homeostasis

– A relatively constant or unchanging internal environment

– Change is monitored and controlled by means of feedback loops

– Variables that are regulated to maintain homeostasis include

• Nutrient content (see #2 for examples of nutrients)• Temperature

• On a larger scale – blood flow, heart rate, breathing rate, etc.

5: Reproduction and Genetic Material

• Living things contain genetic material called DNA (deoxyribonucleic acid) and/or RNA (ribonucleic acid)

• Living things reproduce by copying of their DNA and division of their cells– DNA provides the instructions for making all the

proteins found in living things

• Reproduction is the ultimate goal of all living things – it is their driving force and influences all their other functions

6: Growth and Development

• Living things get larger over time

• Living things go through phases of change over time as they prepare for reproduction

7: Adaptation and Evolution

• Individuals can undergo small changes to acclimate to their environment– These changes are NOT passed on in their genes– For example: leaves on the sunny side of a tree are typically

thicker than the leaves on the shady side

• Populations adapt through changes in their gene pool as some genetic strains survive better than others– For example: when the industrial revolution occurred localized

populations of grey moths survived more often than white moths

• Species evolve over time as certain populations adapt, survive, and reproduce better than others

Viruses – living or non-living?

• Viruses are made of DNA or RNA surrounded by a protein coating– They have no cell membrane (and therefore

are not cells)– They cannot reproduce by themselves

• They must use the machinery of their host’s cells

– They don’t metabolize or use energy– They don’t maintain homeostasis

Studying Science Using the Scientific Method

• The scientific method provides a common set of rules through which we can gain knowledge.

• In order to be able to use the method your research must meet these conditions:– Observable: given the proper equipment anyone

should be able to see the same results as the researcher

– Measurable: results must be able to be OBJECTIVELY counted

– Verifiable: the results must be repeatable– Falsifiable: there must be a way to be proven wrong

The Process of the Scientific Method

1. Observation– Researchers are aware of the world around them

and CURIOUS– They are thinking “hmmm…how does that work,

why did that happen, what if I did this differently?”– These curiosities do NOT have to be biologically

mind-blowing, just thoughtful– Mary’s examples

• I noticed that my pet turtle eats more fish in the summer than in the winter

• I notice that my son is more energetic after a long night of sleep than a short one

• I notice that more people order chicken nuggets if they have kids with them than if they are alone in the car

2. Forming a Hypothesis– This is an EDUCATED guess

• You must either do some research or have some experience with the subject you have observed

• Your guess should only suggest a SINGLE explanation for the phenomenon you observed

– Mary’s examles• My turtle eats more in the summer because his tank is

hotter (and this somehow affects his metabolism so he needs more food)

• The amount of time my son has the energy to play is controlled by the amount of time he sleeps

• The more kids that are in a car the more orders of chicken nuggets they will purchase

3. Experiment– To set up an experiment you need to

consider several variables (changeable factors)

– You will create at least 2 groups when you generate the idea for an experiment• The control group and the experimental group(s)

• CONTROL GROUP – the “norm”, it serves as a basis for comparison

– Mary’s examples» My turtle’s eating habits when his tank is 70°» My son’s playing time when he has slept for 8 hours» The number orders of chicken nuggets per car when

no kids are in the car

• EXPERIMENT GROUP(S) – you change the main or INDEPENDENT variable to test your hypothesis

– Mary’s examples» My turtle’s eating habits when the tank is 80° (group

1); My turtle’s eating habits when the tank is 90° (group 2); etc. (try not to boil the turtle )

» My son’s playing time when he has 6 hours of sleep (group 1); 5 hours of sleep (group 2); etc.

» The number of order of chicken nuggets per car when there is/are 1 kid; 2 kids; 3 kids; etc.

– The Variables – things that could possibly change in your experiment either through your action or without your action…you need to consider them all

• Independent variable– This is the thing you are changing and it is your explanation from your

hypothesis– My examples:

» The temperature of the tank» The number of hours of sleep» The number of kids in the car

• Dependent Variables– This is the thing you will measure…researchers hope their

INDEPENDENT variable will influence their DEPENDENT VARIABLE as expected – that means they were right!

– My examples:» How many fish turtle eats (hopefully more as it gets warmer)» How much playing time my son can tolerate before he falls asleep

(hopefully more when he gets more rest and less when he gets less rest)

» How many orders of chicken nuggets are requested per car

• continued on the next slide…..

• Control Variables– Since we want to FOCUS on the independent and dependent

variables we want to try to eliminate all the confounding factors that could get in the way of our understanding – we want to control these outside influences

– My examples:» I will use all MALE turtles, they will always be OFFERED

10 fish, they will always get 1 INCH GOLDFISH, they will all live in a 5 gallon TANK, they will always have a 10 hour DAY LENGTH, etc.

» I will use only my son as a study SUBJECT, he will always have 3 days of NORMAL sleep patterns before I start an experimental day, he will always start by eating 1 cup of CHOCOLATE CEREAL, he will always have 10 minutes of ACTIVE TIME per hour (jumping jacks or running), etc.

» I will always observe cars at McDonalds (LOCATION), I will observe them from 11 am – 1 pm (TIME), I will only observe vehicles with female drivers (GENDER), I will only observe vehicles with drivers from the AGE of 30-40, etc.

4. Data analysis– This usually involves some statistics to allow

you to objectively compare the data you have collected• It is not based on the researcher’s perceptions of

the data• Data is often represented graphically

– The independent variable should be placed on the X-axis (along the bottom)

– The dependent variable should be placed on the Y-axis (along this side

Turtle Feeding Habits

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60 65 70 75 80 85

Temperature

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5. Conclusions– If your data does not support your

hypothesis• Reject your hypothesis – you are wrong

– If your data does support your hypothesis• Do not reject your hypothesis – you are not

wrong

• But you aren’t necessarily right either– Remember, you have to be able to verify or repeat

these results so you have to continue to research to make sure you have good confidence in your hypothesis

Levels of Confidence• Hypothesis

– An educated guess, keep working!• Theory

– A well supported hypothesis (a proposed explanation of an observed phenomenon)

– Generally a theory has some unanswered questions, potential flaws, or other concerns

– Examples of theories• Cell theory, biogenesis theory, atomic theory, big bang theory, global climate change,

theory of relativity

• Law– A description of an observed phenomenon– Usually scientific laws refer to rules for how nature will behave under certain

conditions. Scientific theories are more overarching explanations of how nature works and why it exhibits certain characteristics. (Wikipedia – “theory”)

– A common misconception is that scientific theories are rudimentary ideas that will eventually graduate into scientific laws when enough data and evidence has been accumulated. A theory does not change into a scientific law with the accumulation of new or better evidence. A theory will always remain a theory, a law will always remain a law.

– Examples of laws• Law of gravity; laws of conservation of mass, energy, and momentum; laws of

thermodynamics; gas laws; electromagnetic laws

From But it's "JUST a THEORY" Version 1.0

Copyright 1999 by Ken Harding [last update August 24, 1999]

• Is Evolution a fact or a theory? – The theory of evolution explains how life on earth has changed. In scientific

terms, "theory" does not mean "guess" or "hunch" as it does in everyday usage. – Scientific theories are explanations of natural phenomena built up logically from

testable observations and hypotheses. Biological evolution is the best scientific explanation we have for the enormous range of observations about the living world.

– Scientists most often use the word "fact" to describe an observation. But scientists can also use fact to mean something that has been tested or observed so many times that there is no longer a compelling reason to keep testing or looking for examples. The occurrence of evolution in this sense is a fact. Scientists no longer question whether descent with modification occurred because the evidence supporting the idea is so strong.

– Why isn't evolution called a law? Laws are generalizations that describe phenomena, whereas theories explain phenomena. For example, the laws of thermodynamics describe what will happen under certain circumstances; thermodynamics theories explain why these events occur. Laws, like facts and theories, can change with better data. But theories do not develop into laws with the accumulation of evidence. Rather, theories are the goal of science.

– WATCH FOR AN UPCOMING EXTRA CREDIT DISCUSSION ON THEORIES AND LAWS!!!