Concepts & Methods in Biology
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Transcript of Concepts & Methods in Biology
Concepts & Methods in Biology
Chapter 1
What is the goal of science?
Investigate and understand natureExplain events in naturePredict events from explanations
How is science studied?
ObservationsHypothesisExperimentationData collection and analysisConclusions
Observations
Quantitative
Observations based on numbers or quantities.
Ex. 15 miles, 100 people
Qualitative
Observations that are descriptive.
Ex. Cloudy sky, large teeth
Collection of data or evidence using the senses
Objective Observations vs. Subjective Observations
Objective –without a predetermined view point (unbiased)
Subjective – a predetermined view point, misleading (biased)
Dangerous – Jewish people are inferior to Germans
Inductive Logic
Using observations and facts to arrive at
generalizations or hypotheses
Observation: Eagles, swallows, and robins
have feathers
Hypothesis: All birds have feathers
Deductive Logic
Drawing a specific conclusion based on a
generalization
– Generalization - Birds have feathers
– Example - Eagles are birds
– Conclusion - Eagles have feathers
CHILDBED FEVERA Nineteenth-Century
Mystery
Background
When: 1844-1860.Where: Vienna, AustriaSituation: Healthy women would deliver their babies and a few days later would be dead of childbed fever. Women who gave birth at home rarely died of childbed fever. Some women begged to give birth without medical attention in the street and be admitted to the hospital after the delivery.
Part 11. What were Semmelweis’ initial
observations?
2. What was the problem at hand?
3. What possible story might Semmelweis come up with to explain his problem?
4. How might Semmelweis test his suspicions?
Part 21. Based on the information what possible
story might Semmelweis come up with to explain the problem?
2. How could Semmelweis test his new hypothesis?
Part 31. What conclusions can Semmelweis'
make about his experiment?
2. How might Semmelweis revise his original hypothesis or his experiments to gain additional information?
Part 41. What, if any, role did serendipidity play in
Semmelweis’ story of childbed fever?
What happened next?
Findings were met with hostility or dissmissed.Was not able to retain his teaching post.Returned to Hungary and was successful in ridding the St. Rochus hospital of the disease.Published his findings once again and once again they were dismissed.
Semmelweis suffered a mental breakdown due to his constant rejection and eventually died of childbed fever, puerperal sepsis.
Scientific Method
How does the case of childbed fever illustrate the use of the scientific method?
Go back through this case and indicate where the following parts of the following parts of the scientific method are found: observation, problem, hypothesis, experiment, conclusion
Hypothesis
A possible answer to a scientific question or an explanation for a series of observations.
What was Ignaz Semmelweis’s initial hypothesis after his friend died of child bed fever?
Role of Experiments
Procedures used to study a phenomenon under known conditions
Allows you to predict what will happen if a hypothesis is not wrong
Can never prove a hypothesis 100% correct
Experimental Design
Control group – A standard for comparison– Identical to experimental group except for
variable being studied
Sampling error– Non-representative sample skews results– Minimize by using large samples
Data Recording and Analysis
Clear, precise and objective.
What was the data and analysis from Semmelweis’s experiment?
Conclusion
Evidence supports or refutes the hypothesis.
How Scientist Work
Examples:
Examples:Maggots come from
meatMice from wheat Beetles from cow dung
Spontaneous Generation
Belief that living things arose from non-living things
Their Explantation
Gods, witchcraft, mythology, devil
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.HYPOTHESIS: Flies produce maggots.PROCEDURE
Controlled Variables:jars, type of meat,location, temperature,time
Manipulated Variables:gauze covering thatkeeps flies away from meat
Uncovered jars Covered jars
Several days pass
Maggots appear No maggots appearResponding Variable: whether maggots appearCONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous
generation of maggots did not occur.
Section 1-2Francesco Redi and Spontaneous Generation
What is Redi’s Conclusion?
Spontaneous generation does not occur.
The Return of Spontaneous Generation
Lazzaro Spallanzini – improves Needham’s experiment
Anton van Leeunwenhoek – uses a microscope to find tiny organisms swimming in pond water.
“animulcules”
John Needham (mid 1700’s) performs an experiment that refutes Redi
Gravy is boiled. Flask isopen.
Gravy is teeming with microorganisms.
Gravy is boiled. Flask issealed.
Gravy is free of microorganisms.
Section 1-2
Figure 1-10 Spallanzani’s Experiment
What are the controlled variables?
What are the manipulated variables?
The debate continues
Louis Pasteur – 1864, his experiment finally disproved spontaneous generation
Pasteurization
In the 1800’s some believe the air contained a “life force” perpetuating the belief of spontaneous
generation.
Broth is boiled. Broth is free ofmicroorganismsfor a year.
Curved neckis removed.
Broth is teeming with microorganisms.
Section 1-2
Figure 1-11 Pasteur’s Experiment
Broth is boiled. Broth is free ofmicroorganismsfor a year.
Curved neckis removed.
Broth is teeming with microorganisms.
Figure 1-11 Pasteur’s Experiment
Broth is boiled. Broth is free ofmicroorganismsfor a year.
Curved neckis removed.
Broth is teeming with microorganisms.
Figure 1-11 Pasteur’s Experiment
Limits of Science
Scientific approach cannot provide answers to subjective questions
Cannot provide moral, aesthetic, or philosophical standards
Scientific Theory
A hypothesis that has been tested for its predictive power many times and has not yet been found incorrect
Has wide-ranging explanatory power– Darwin’s Theory of Evolution by Natural
Selection
Science and the Supernatural
Science has run up against religious belief
systems– Copernicus suggested that sun, not the Earth,
was center of universe
– Darwin suggested that life was shaped by
evolution, not a single creation event
Asking Questions
Scientists still ask questions that challenge widely held beliefs
The external world, not internal conviction, is the testing ground for scientific beliefs
Why Study Biology?
To learn how organisms are constructed, how they function, where they live, and what they do
To help you develop, modify, and refine your ideas about life
Studying Life
What do all living things have in common?
List 5 things that all living things do.
Is a hurricane alive?
Are flowers alive?
Is a fire Alive?
Is a dragon fly Alive?
Is a river alive?
Is a crowd alive?
The characteristics of living things
Living Things are Made of Cells
Unicellular vs. multicellular
All living things reproduce.
Asexual Reproduction - the new organism has a single parent, clone
Sexual Reproduction - 2 cells from separate parents unite to produce the first cell of an
organism
Universal Genetic Code
DNA - deoxyribose nucleic acid
DNA (Deoxyribonucleic acid)
The signature molecule of life
Molecule of inheritance
Directs assembly of amino acids
Heritability of DNAInheritance
–Acquisition of traits by way of transmission of DNA from parent to offspring
Reproduction –Mechanisms by which an organism
produces offspring –Governed by instructions in DNA
DNA Guides Development
Development
– Transformation from fertilized egg to adult
– Series of stages
– Instructions for each stage in DNA
Growth and Development
Need for materials and energy.
Nothing Lives Without Energy
Energy = Capacity to do work
Metabolism = Reactions by which cells acquire and use energy to
grow, survive, and reproduce
Response to the Environment
Sensing and Responding
Organisms sense changes in their environment and make responses to themReceptors detect specific forms of energy The form of energy detected by a receptor is a stimulus
Maintaining an Internal Balance (Homeostasis)
Homeostasis
Maintenance of internal environment within range suitable for cell activities
Pancreas maintains level of sugar in blood by secreting hormones
Evolution - as a group all living things change over time
Evolution
Genetically based change in a line of descent over timePopulation changes, not individuals
Mutation: Source of Variation
Mutation = change in structure of DNA
Basis for the variation in heritable traits
Most are harmful
Unity of Life
All organisms: –Are composed of the same substances–Engage in metabolism–Sense and respond to the environment–Have the capacity to reproduce based
on instructions in DNA
What is Life Follow-up
Yeast is unicellularSci Name Saccharomyces cerevisiae“ Sugar loving”Found naturallyFermentationAsexually by buddingSexually by spores
What are the different levels of organization in Biology?
Smallest to Largest
Subatomic Particles
Electron, Proton, Neutron or some other fundamental unit of matter
Atom
Smallest unit of an a element that retains the properties of that element
Molecules - groups of atoms
Organelle
Membrane-bound internal compartment for specialized reactionsNot found in most prokaryotic cells
Cells - smallest functional unit of life
Basic Unit of Life - The Cell
Characteristics of life emerge at the level of cells
A cell is the smallest unit having the capacity to live and reproduce
Tissues
Organs
Organ Systems
Organism - an individual living thing
Population - group of organisms of one type living in the same area
Community - Populations that live together in a defined area
Ecosystem - community and its nonliving surroundings
Biosphere - Part of the Earth that contains all ecosystems
Interdependencies Among Organisms
ProducersMake their own food
ConsumersDepend on energy stored in tissues of producers
DecomposersBreak down remains and wastes
Energy Flow
Usually starts with energy from sunTransfer from one organism to anotherEnergy flows in one directionEventually, all energy flows back to the environment
Fig. 1.6, p. 7
PRODUCERS
CONSUMERS,DECOMPOSERS
NUTRIENT CYCLING
ONE-WAY FLOW OF ENERGY
Producers capture, convert, and use or store some energy from the sun.
Energy gets transferred from one organism to another; in time, all flows back to the environment.
It is this one-way flow of energy that creates the interdependencies or connections among organisms If we understand these, how will it help us understand our role?
Diversity of Life
Millions of living species
Additional millions of species now
extinct
Classification scheme attempts to
organize this diversity
Scientific Names
Two-part naming system devised by
Carolus Linnaeus
First name is genus (plural, genera)– Homo sapiens - genus is Homo
Second name is species within genus
Three Domains of life
BacteriaArchaeaEukarya
TaxaDomainKingdomPhylumClassOrder FamilyGenus Species
The Six Kingdoms
Archaebacteria or Archaea
Eubacteria
Protista
Fungi
Plantae
Animalia
Prokaryotic Kingdoms
Archaebacteria and Eubacteria
Single cells
No nucleus or organelles
Includes producers, consumers, and
decomposers
Eukaryotic Kingdoms
Protista, Fungi, Plantae, Animalia
DNA is inside a nucleus
Most are larger and more complex than the prokaryotes
Protistans
Not an easily defined group
Producers and consumers
Single-celled and multi-cellular species
Fungi
Most are multicelled
Consumers and decomposers
Extracellular digestion and absorption
The yeast you studied
Plants
All are multicelled
Most are photosynthetic producers
Make up the food base for communities, especially on land
Animals
Multicelled consumers– Herbivores – Carnivores– Parasites – Scavengers
Move about during at least some stage of their life
End of Chapter 1
Blue Card
Place in order (smallest to largest)Class, Genus, Kingdom, Order, Phylum, Family, Species, Domain
Unit 1 Exam
28 Mult. Choice6 Fill-in the blanks14 Short answers