biological science 10: principles of biology - gavilan...

Biological Science 10: Principles of BiologyTuesday and Thursday 8:10-9:30 LS101Instructor: John Crocker phone (408) 852-2835 Email: jcrocker@gavilan.eduOffice: LS117 Office Hours: Tues 9:30-11:30 or by appointmentRequired Texts:Audesirk, Audesirk & Byers Life On Earth, Pearson

Custom Publishing-Gavilan College.Laboratory Manual for Biological Science 10, Gavilan

College.

Course Goals: 1. Think critically about facts and issues in science.2. Describe key characteristics of all living things3. Describe essential biological structures and processes

that occur at the molecular, cellular, and organismal levels that enable life.

4. Explain gene function and the role of genes in inheritance and evolution.

5. Explain and practice the scientific method of inquiry.6. Describe ecological interactions that occur within

ecosystems, communities, and populations. 7. Recognize biological processes in your daily life. 8. Effectively organize and present information to a group

Grading Policy: Lecture (67%): 3 exams at 100 points each (drop 1) 55%

Homework/Quizzes 20%Final Exam 25%

Laboratory (33%) Lab reports/ presentations 70%Lab Quizzes 30%

A= 90% and up (A-=89.5) NRS= withdrawal during weeks 1-5 B= 80-89% (B+88; B-79.5) W= withdrawal during weeks 6-14 C= 70-79% (C+=78) F= failure to notify instructor of withdrawal or D= 60-69% withdrawal after week 14F= less than 60% I= incomplete (for unforeseen and justifiable reasons, or

emergency; may be granted only after week 14

-Please note that this point system is tentative and may change slightly. -As per college policy, students missing one more class hour than the unit value of the course may be

dropped. (However, it is your responsibility to drop the class (either through admissions, in person or by telephone.) You are responsible for all material covered in class. If you foresee missing more than one or two days of class, please inform me.

-Students requiring special services or arrangements because of hearing, visual, or other disability should contact their instructor, counselor, or the Disability Resource Center

-Students are expected to exercise academic honesty and integrity. Violations such as cheating and plagiarism will result in disciplinary action which may include recommendation for

dismissal. This further discussed in the Student Handbook. Expected conduct during examinations is discussed in the last page of this handout.

Please take out pen or pencil and paper

1. Define the term Biology.2. What is the scientific method?3. List the steps of the scientific method.4. Define the term hypothesis.5. Define the term theory.6. List three evidences in support of the theory of evolution.7. What are the common characteristics of all living things?8. List the levels of organization of life beginning with the smallest and

progressing up in complexity to communities of multiple species.9. What is DNA?10. What is a species?11. What is speciation?12. The pictured organism is most closely related to

a) Spongesb) Coralsc) Humansd) Grey aliense) Nothing, I made it in Photoshop

1. The science of life and of living organisms, including their structure, function, growth, origin, evolution, and distribution. Botany, zoology, and ecology are all branches of biology.

2. A systematic approach to solving a problem by gathering knowledge, investigating a phenomenon, testing, and integrating previous knowledge.

3. Slide 184. A tentative explanation for (a group of) phenomena, (a set of) facts, or a scientific inquiry that is

testable and falsifiable5. a well-substantiated explanation or a set of statements that have been confirmed over the course

of many independent experiments6. Many possible choices, including but not limited to: universality of DNA, prevalence of “left-

handed” molecules in living things, repeated discoveries of “missing links” in the fossil record (feathered dinosaurs etc), genetic tracking (mitochondrial DNA etc)

7. a) organized and complexb) grow and reproducec) respond to stimulid) acquire and use material and energye) use DNA to store information

1. Cell, tissue, organ, organ system, organism, population, community2. deoxyribonucleic acid, a double-stranded nucleic acid that contains the genetic information for cell

growth, division, and function. 3. a group of organisms having common characteristics and (usually) capable of mating with one

another to produce fertile offspring4. Creation of a new species, usually caused by a population being split by a natural barrier.5. c) Humans These are tunicates (sea squirts); they are chordates like us.

Copyright © 2009 Pearson Education, Inc..

Lectures byGregory Ahearn

University of North Florida

Modifed byJohn Crocker

Chapter 1

An Introduction to Life on Earth

Why Study Biology?

Biology helps you understand your body.

Biology helps you become an informed citizen.

Biology can open career opportunities.

Biology can enrich your appreciation of the world.

Scientific Principles

Biology is a scientific discipline All scientific inquiry is based on a small set

of assumptions or principles• Natural causality• Uniformity in space and time• Similar perception

Natural Causality

Historical approaches to studying life1. Belief that some events happen through

supernatural forces (e.g. the actions of Greek gods)

1. Belief that all events can be traced to natural causes that we can comprehend (natural causality)• Corollary: Evidence gathered from

nature has not been deliberately distorted to fool us

Natural Laws Apply Everywhere

Natural laws are uniform in space and time This principle is key understanding

biological events (e.g. evolution) that occurred before humans recorded them

Natural Laws Apply Everywhere

Creationism is contrary to the principle of uniformity-in-time and natural causality• Creationists hold that different species were

created one at a time by the direct intervention of a supernatural being

Similar Perceptions

Assumption that all human beings perceive natural events in fundamentally the same way

Common perception allows us to accept observations of other humans as reliable

Similar Perceptions

Common perception is usually not found in appreciation of art, poetry, and music, nor between cultures or religious beliefs• Value systems are subjective• Science requires objectively gathered data

The Scientific Method

Scientific inquiry is a rigorous method for making observations

The Scientific Method for inquiry follows 4 steps…

The Scientific Method

1. Observation of a phenomenon– Subsequent development of

questions2. Formulation of a hypothesis

– A supposition that explains an observed phenomenon, leading to testable predictions

The Scientific Method

1. Testing through experimentation– Additional controlled observations

2. Development of a conclusion– Evaluation of hypothesis in light of

experimental data

The Scientific Method

Scientific experimentation tests the assertion that a single variable causes a particular observation

The experiment must rule out the influence of other possible variables on the recorded observations

The Scientific Method

Controls are incorporated into experiments

Controls keep untested variables constant Scientific method is illustrated by

Francesco Redi’s experiment

Application to Everyday Problems

Assume you are late for an appointment and hurriedly try to start your car

1. Observation: The car won’t start

Application to Everyday Problems

1. Hypothesis: the battery is dead

Application to Everyday Problems

1. Experimental design: Replace your battery with another and restart the car

Application to Everyday Problems

1. Premature conclusion:• The problem was a dead battery

because the car starts when replaced with a different one

Application to Everyday Problems

1. Recognition of inadequate controls• Did you attempt to start the car

more than once?• Was the battery cable on my

original battery loose?

Application to Everyday Problems

1. Establishing a controla. Reinstall your old battery, check for

tight cables, now try to start the carb. If car still fails to start on old battery,

the only variable in this investigation now is the effectiveness of the battery

Application to Everyday Problems

1. Making a better conclusion, based on controlled experiments• Your battery was probably dead

Question: Have all other variables been eliminated?• Example: loose battery cables• Example: broken electrical wires

Solution: Control for other variables• Make sure cables are tight.• Make sure electrical wires are in good

condition.

Limitations of the Scientific Method

Can never be sure all untested variables are controlled

Conclusions based on the experimental data must remain tentative

Limitations of the Scientific Method

Results of experimentation must be communicated thoroughly and accurately to other scientists for repetition

Repetition by other scientists add verification that findings can be used as the basis for further studies

Science Is a Human Endeavor

Human personality traits are part of “real science”

Scientists, like other people may be driven by pride, ambition, or fear

Scientists sometimes make mistakes Accidents, lucky guesses, intellectual

powers, and controversies with others contribute strongly to scientific advances

Science Is a Human Endeavor

1.In the 1920s, bacteriologist Alexander Fleming grew bacteria in cultures

2.One of the bacterial cultures became contaminated with a mold

3.Fleming nearly destroyed the culture when he noticed the mold (Penicillium) inhibited bacterial growth in the culture

Fig. 1-7

1.2 How Do Biologists Study Life?

Penicillin kills bacteria.

A petri dishcontains solidgrowth medium

Bacteria grow ina pattern createdby streaking

A substance fromthe mold diffusesoutward and inhibitsthe growth ofnearby bacteria

A colony of themold Penicillium

Science is a Human Endeavor

1. Fleming hypothesized that the mold produced an antibacterial substance

2. Further tests using broth from pure Penicillium cultures lead to the discovery of the first antibiotic, penicillin

Science is a Human Endeavor

1. Fleming continued beyond a lucky “accident” with further scientific investigation to a great discovery

2. “Chance favors the prepared mind” (Louis Pasteur)

Scientific Theory

A scientific theory differs in definition from that of everyday usage• Many people use the word theory to mean

hypothesis, and “educated guess”

Scientific Theory

A scientific theory is a general explanation for important natural phenomena• It is extensively and reproducibly tested• It is more like a principle or natural law (e.g.

the atomic, gravitational, and cell theories)• If compelling evidence arises, a theory may

be modified

Scientific Theory

New scientific evidence may prompt radical revision of existing theory

Example: the discovery of prions…

Scientific Theory

Before 1980, all known infectious diseases contained DNA or RNA

In 1982, Stanley Prusiner showed that the infectious sheep disease scrapie is caused by a protein (a “protein infectious particle” or prion)

Scientific Theory

Prions have since been shown to cause “mad cow disease” and diseases in humans

The willingness of scientists to revise accepted belief in light of new data was critical to understanding and expanding the study of prions

Science Is Based on Reasoning

Inductive Reasoning• Used in the development of scientific

theories• A generalization is created from many

observations• e.g., the cell theory (all living things are

made of one or more cells) arises from many observations that all indicate a cellular basis for life

Science Is Based on Reasoning

Deductive Reasoning• Generating hypotheses based on a well-

supported generalization (such as a theory)• e.g., based on the cell theory, any newly

discovered organism would be expected to be composed of cells

Fig. 1-5

1.2 How Do Biologists Study Life?

Life can be studied at different levels of organization.

nerve cell

community

tissue

organ

organism

population

cell

nervous tissue

brain

snakes, antelope, hawks, bushes, grass

herd of pronghorn antelope

pronghorn antelope

Fig. 1-8

1.3 What Is Life? Characteristics of living things

Complex and OrganizedComposed of CellsRespond to StimuliMaintain Relatively Constant Internal Conditions

Through HomeostasisAcquire and Use Materials and EnergyGrow and Reproduce ThemselvesLiving Things as a Whole Have the Capacity to

Evolve

Living Things Are Composed of Cells

Living things are complex and organized

Living Things Are Composed of Cells

The cell theory states that the cell is the basic unit of life

A single cell has an elaborate internal structure

Living Things Are Composed of Cells

All cells contain:Genes that provide information to direct

the cellOrganelles, small specialized structures

that perform specific functionsA plasma membrane that encloses the

fluid cytoplasm and organelles from the outside world

Homeostasis

Organisms must maintain relatively constant internal conditions (homeostasis)e.g. many organisms regulate body

temperature

Homeostasis

Homeostatic mechanisms includeSweating in hot weather or dousing oneself

with cool waterMetabolizing more food, basking in the sun,

or turning up the thermostat in cold weather

Organisms still grow and change while maintaining homeostasis

Living Things Respond to Stimuli

Organisms sense and respond to internal and external environmental stimuliSensory organs in animals can detect and

respond to external stimuli like light, sound, chemicals, etc.

Internal stimuli in animals are perceived by stretch, temperature, pain, and chemical receptors

Plants and bacteria respond to stimuli as well (e.g. plants to light, bacteria to available nutrients in the medium)

Living Things Acquire Materials

Materials and energy required to maintain organization, to grow, and to reproduce

Living Things Acquire Materials

Important materials (nutrients) acquired from air, water, soil, or other living things

Nutrients are continuously recycled among living and nonliving things

Living Things Acquire Materials

Nutrients are incorporated into the bodies of organisms

Metabolism is the sum total of all the chemical reactions needed to sustain an organism’s life

Living Things Acquire Materials

Organisms obtain energy in two waysPlants and some single-celled organisms

capture sunlight in photosynthesis. Other organisms consume energy-rich

moleculesAll energy that sustains life comes directly or

indirectly from the sun

Living Things Grow

Every organism becomes larger over time Plants, bird, and mammals grow by

producing more cells to increase their mass

Bacteria grow by enlarging their cells; they also divide to make more individuals

Growth involves the conversion of acquired materials to molecules of the organism’s body

Living Things Reproduce Themselves

Organisms give rise to offspring of the same type (reproduction)

The parent’s genetic material (DNA) is passed on to the offspring, creating continuity of life

Diversity of life occurs because offspring may be genetically different from their parents

Capacity to Evolve

The genetic composition of a whole species changes over many generations

Mutations and variable offspring allow a species to evolve

Capacity to Evolve

Evolutionary theory states that modern organisms descended with modification from pre-existing life-forms

Natural selection is a process where organisms with certain adaptations survive and reproduce more successfully than others

1.4 Why Is Life So Diverse?

DNA: The universal molecule of life• DNA is found in the bodies of all organisms,

from bacteria to whales.• Its universal presence suggests that all

organisms have descended from a common ancestor having the same molecule.

1.4 Why Is Life So Diverse?

Life’s unity and diversity is a result of evolution.• Life changes over long periods of time.• Groups of organisms change from generation

to generation.• The changes that accumulate in populations

of organisms over time is called evolution.

Unifying Theory of Biology

Evolution explains how diverse forms of life originated through changes in their genetic makeup Modern organisms descended with

modification from pre-existing life formsEvolution arises as a consequence of three

natural processes…

Three Natural Processes Underlie Evolution

Genetic variation among members of a population

Inheritance of those variations by offspring of parents carrying the variation

Natural selection of individuals whose survival and enhanced reproduction are due to the favorable variations they carry

Genetic Variability

Genetic variation arises from segments of DNA (genes)

Changes in genes (mutation) alter the informational content

Mutations arise from a number of sourcesMutations can occur from irradiationMutations occasionally arise from copying

mistakes in DNA during cellular reproduction

Genetic Variability

Effects of mutationNo effect (harmless)A decrease in organism’s ability to

functionDeath of the organismAn increase in an organism’s ability to

survive and reproduce (rare)Mutations occurring over millions of years

and passed through many generations cause members of a species to be slightly different

Natural Selection

Organisms that best meet environmental challenges leave the most offspring

Natural selection preserves genes that help organisms flourish

Natural Selection

Adaptations are structures, physiological process, or behaviors that aid in survival and reproduction

Adaptations that are good for one environment may be poor in another

Natural Selection• Species that cannot adapt to environmental

change go extinct

Natural Selection

The many different habitats (environments) in an area coupled with evolutionary adaptive processes produce species variety or biodiversity

Humans are responsible for accelerating the rate of environmental change (and therefore the rate of extinction of species)

Categorizing Life

Organisms can be grouped into three domainsBacteria (single, simple cells) Archaea (single, simple cells) Eukarya (one or more highly complex

cells)

Categorizing Life

Domain Eukarya contains four subdivisions or kingdomsFungiPlantaeAnimaliaThe “Protists”

Categorizing Life

There are exceptions to any simple set of rules used to distinguish the domains and kingdoms, but three characteristics are particularly usefulCell typeThe number of cells in each organismEnergy acquisition

Prokaryotic and Eukaryotic Cells

Cell types named after presence or absence of a nucleusThe nucleus is a membrane-enclosed sac

containing the cell’s genetic material

Prokaryotic and Eukaryotic Cells

Two cell types seen among all living thingsProkaryotic (“before nucleus” in Greek)

Only 1-2 micrometers in diameterLacking organelles or a nucleusCell type found in Domains Bacteria and

Archaea

Prokaryotic and Eukaryotic Cells

Eukaryotic (“true nucleus” in Greek)Larger than prokaryotic cellsContain a variety of organelles, including

a nucleusCell type found only among members of

Domain Eukarya

Unicellularity vs. Multicellularity

Unicellular (single-celled) organisms found in:BacteriaArchaeaThe protists in Eukarya

Unicellularity vs. Multicellularity

Multicellular (many-celled) organisms found in EukaryaKingdom FungiKingdom PlantaeKingdom Animalia

Ways Organisms Acquire EnergyAutotrophs (“self-feeders”)

Photosynthetic organisms that capture sunlight and store it in sugar and fats

Includes plants, some bacteria, and some protists

Ways Organisms Acquire EnergyHeterotrophs (“other-feeders”)

Organisms that acquire energy through ingesting molecules in the bodies of other organisms

Includes many archaeans, bacteria, protists, fungi, and animals

Size of food eaten varies from individual food molecules to ingestion and digestion of whole chunks