biological science 10: principles of biology - gavilan...
TRANSCRIPT
Biological Science 10: Principles of BiologyTuesday and Thursday 8:10-9:30 LS101Instructor: John Crocker phone (408) 852-2835 Email: [email protected]: 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