welcome to biol406 paloma valverde, phd [email protected] office: ira allen building, room 218
TRANSCRIPT
Course Description
Biol 406 introduces fundamentals principles of biology
Cell structure
Metabolism
Reproduction and Genetics
Classification of living organisms
Animal anatomy,physiology and evolution
The influence of biology in our society.
Instructional Methodologies This course can be defined as a hybrid since approximately 30-
40% of it involves online-like activities and/or online delivery.
This course will use blackboard and connectplus to post grades, announcements, assignments, power point presentations, lab handouts and interactives.
Students will be required to keep a lab manual including wet and dry lab-related activities.
Students will work individually or in groups to discuss or write about current topics in biology. Students will also deliver a final project to the class by using lecture-capture technology. Office hours will be available both online and on-site.
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Online component of the courseLabs 1, 2, 7, 10 and 13 are online labs.
Special topics sessions on Fridays are onlineYou do not have to go to class/lab on those days, but you have
to complete the activities the day of the lab or special topic.
At the completion of the activity: Send email to me indicating you completed it and did not have any problems
If Problems with the activity: Ask me and I will help you (during those sessions you can come to my office or call me). Use google chat/office phone
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Required Text Book and Online Technologies
http://connect.mcgraw-hill.com/class/p_valverde_spring2011
Text book is called: Biology, 10th Edition, Mader, McGraw-Hill
Link above: electronic book and online assignment technology (buy Connectplus) $97
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Other needs
• Get a free gmail account to be able to use google voice/video chat and google docs.
Go to: mail.google.com
To create an account if you do not have one
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Blackboard account
• Lab handouts
• Power point presentations
• Assignments
• To register for the first time:
Username: your wentworth username
Password: 654321
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Paloma Valverde, PhDAssistant Professor, SciencesOffice Location: Ira Allen Building 218Email: [email protected] hours: M/T/Th/F 12-12:50 pmOffice phone: 617-989-4439 (and to contact by Google voice/video
chat, Gmail: [email protected])
Biology, Life and The Scientific Method
Week 1 lecture: Chapters 1
Outline
• What is biology?
• What are the properties of life/living organisms?
• How biologists use the scientific method to study life
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What is biology?
• In its broadest sense, biology is the study of life and consists of many disciplines (biochemistry, cell biology, zoology, botany, ecology…)
Properties of Living OrganismsLiving things shared 7 characteristics:– are highly organized– are composed of 1 or many cells (a cell is the basic unit of
life)– interact with other living organisms and the environment,
and respond to them– can grow and reproduce– acquire materials and use energy to perform work – maintain a state of internal balance within the tolerance
range of the organisms. – adapt and modify with time (evolution) to make organisms
suited to their way of life
Levels of Organization
Biosphere
Ecosystem
Community
Population
Organism
Organ system
Organ
Tissue
Cell
Molecule
Atom
Smallest unit of matter
Smallest unit of life
Cellular levelMuscle cell
Tissue levelMuscle tissue
Organ levelHeart
Organ system levelCirculatory system
Organism levelMany organ systemsfunctioning together
A B
C
D
E
1)A population consists of all organisms of the same species (look alike and can interbreed) in a particular area2) A community consists of all of the local interacting populations3) An ecosystem consist of aspects of a community and the physical environment (soil, atmosphere, etc)4) The biosphere (our planet Earth) consists of different ecosystems that interact with each other. The Biosphere is the zone of air, land and water where organisms exist
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Energy is needed to survive
• Energy – required to maintaining organization and conducting life-sustaining processes
– The sun is the ultimate source of energy for nearly all life on Earth
– Certain organisms, such as plants, capture solar energy to carry on photosynthesis (autotrophs). Photosynthesis transforms solar energy into chemical energy by producing Organic Molecules (with C)
– Chemical energy is used by other organisms by the process of cellular respiration e.g. animals (heterotrophs)
– Metabolism is all the chemical reactions that occur in a cell or in an organism to maintain life.
– Two categories: Catabolism (breaks down organic molecules), ex in cellular respiration; anabolism uses energy to contruct large molecules such as proteins and nucleic acids.
Homeostasis is another characteristic of life
– Homeostasis - Maintenance of internal conditions within the tolerance range of the organism (temperature, moisture level, pH…)
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Living Things: Respond to Stimuli
• Living organisms interact with other living organisms and with the environment and respond to stimuli or changes
• Response ensures survival of the organism and it often results in movement
– Vulture can detect and find carcass a mile away and soar toward dinner
– Monarch butterfly senses approach of fall and migrates south
– Microoganisms can sense light or chemicals
– Leaves of plants follow sun
• The collective responses of an organism constitute the behavior of the organism
Living Things: Reproduce and Develop
• Organisms are born, grow and then die
• All living organisms must reproduce to ensure continued existence and maintain population
• Developmental instructions encoded in genes
• Composed of DNA
Living Things: Adapt to Change• Adaptation
– Any modification that makes an organism more suited to its way of life
– Organisms become modified over long period time
• Respond to environmental changes by developing new adaptations
Living things: Evolve• Because organisms can adapt, they can also evolve.
• Evolution: modification of a species over generations
• Despite diversity, organisms share the same basic characteristics – Composed of cells organized in a similar manner– Their genes are composed of DNA – Carry out the same metabolic reactions to acquire
energy
• This suggests that they are descended from a common ancestor organism that lived on the Earth millions of years ago
1) Many biological studies use the scientific method and lab experimentation
2) Statistical methods are essential scientific tools
3) Not all forms of inquiry in biology involve lab experimentation, some are discovery-based or may be involve tests by observation.
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How does Biology study Life?
Biology is the scientific study of life. Many biological studies involve the use of the scientific method.
Steps in the scientific method:• Based on careful observations, scientists can develop a
hypothesis • A hypothesis is a possible explanation to an observation
that allows for predictions to be made. • Scientists do experiments and data collection to test the
validity of the hypothesis (by seeing if the predictions come true). If the predictions do not come true the hypothesis is falsified (proven wrong)
• Scientists reach to a conclusion
Biology and the Scientific Method
Developing a good Hypothesis
• A hypothesis must be testable (able to be proven valid through experiments) and falsifiable (able to be proven not valid)
• Sometimes a biologist will develop a main hypothesis and alternative hypothesis and do two or more experiments to save time and resources
• Scientist can develop experiments to prove that a main hypothesis is right and experiments to falsify another hypothesis.
• For example,– Observation: Your flashlight
doesn’t work– Question: Why doesn’t your
flashlight work?– Hypothesis 1: The batteries are
dead– Hypothesis 2: The bulb is burnt out
• Both of these hypotheses are testable with experiments
• Experiments allow to falsify the hypothesis (invalid hypothesis) or not falsify the hypothesis (valid hypothesis)
Observations
Question
Hypothesis #1:Dead batteries
Hypothesis #2:Burnt-out bulb
Prediction:Replacing batterieswill fix problem
Prediction:Replacing bulbwill fix problem
Test prediction Test prediction
Test falsifies hypothesis Test does not falsify hypothesis
Experiments
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Controls, Variables and Controlled experiments
The experiment (s)
-tests the hypothesis
-must be carefully designed to test only one variable (factor that influences the experiment, for example temperature) at a time
-In a controlled experiment you will compare IN PARALLEL an experimental group (in which one variable is changed) with a control group (in which the variable is not changed)
Example of Controlled Experiment
Example: You have to test a new miracle food in a group of overweight poodles.
Variable: Miracle food
Control group: Half of the poodles will be fed with regular foodExperimental group: The other half of the poodles will be fed
with miracle food
Results of the experiment:Control group: Overweight Poodles gain weightExperimental group: Overweight Poodles lose weightConclusion: The miracle food helps overweight poodles lose
weight
Theories in Science
A Scientific Theory is the best current explanation for an observation that is supported by a broad range of observations, experiments and data (a much greater body of evidence than a hypothesis)
A hypothesis may become a theory if a lot of evidence is found for its validity: An example of this is “Darwin’s theory of natural selection”
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Example of Scientific Inquiry in Biology: Darwin and his theory of evolution
Darwin was an English naturalist that served on a 5 years-long mapping expedition around coastal South America in 1831 (he was 22 years old) on board of the Beagle.
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Darwin’s Evidence: The beaks of the Galapagos Finches
Darwin observed 14 species of finches in the Galapagos Islands, and noticed variations in their beaks and in what they ate in the different islands.
Darwin proposed that the different beaks represented evolutionary adaptations that improved their ability to eat the foods available in the different islands
Darwin formulated the hypothesis that evolution occurs because of natural selection
evolution: modification of a species over generations
natural selection:
1)Individuals that are best adapted to their environment are more likely to survive and reproduce
2) Over time, more individuals in a population will have the advantageous traits
In other words, the natural environment “selects” for beneficial traits: “The survival of the fittest”
Post-Darwin Evolution Evidence
- New fossils are found all the time that suggest evolution has happened
- Anatomical similarities between different organisms also suggest we have had a common ancestor
Darwin’s initial hypothesis became a theory because of the large amount of evidence that supported it.
Observation
New observationsare made, and previous
data are studied.
Hypothesis
Input from varioussources is used to formulate
a testable statement.
Conclusion
The results are analyzed,and the hypothesis issupported or rejected.
Scientific Theory
Many experiments andobservations support a
theory.
Experiment/Observations
The hypothesis istested by experiment
or further observations.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
The Scientific Method in Biology
“possible and testableexplanation for an observation”
“best current explanation for an observation”“lots of evidence supports its validity”
Lab 1 & Special Topic 1 (R) Lab 1: Tutorial about the Scientific methodWe will do this one face-to-face in the lab (ANXNO003), but in the future you can do online labs on your own)Need a computer/Work in group.Do online with your computer (use lab handout on blackboard) but write answers in hard copy Lab handouts collected and graded twice during the semester (electronic handouts are not accepted)(F) Special topic 1 and Assignment 1: Exobiology/Astrobiology; the scientific method in action We will do those one face-to-face in class but in the future you can work on your own or in groups on the special topics and send by email to me ([email protected])