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