Introduction to Biology - Valverdevalverdescience.pbworks.com/w/file/fetch/108826360... · 2020. 9....

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2- Introduction to Biology

Transcript of Introduction to Biology - Valverdevalverdescience.pbworks.com/w/file/fetch/108826360... · 2020. 9....

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    Introduction to Biology

  • Why is Biology important?

    ● To study DNA: forensics ● Health, medicine. ● Agriculture ● Animals ● Bacteria/ Viruses !

    ● BIO=life ● LOGY=study ● Biology : The study of life

  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.1-

  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.1-

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    Why a Study of Biology is Important?

    Personal • To be informed • Support your cause • Make it your life work

    http://articles.orlandosentinel.com/2011-04-06/health/os-killer-amoeba-research-20110406_1_killer-amoeba-naegleria-fowleri-primary-amebic-meningoencephalitishttp://peopleofperu.org/https://www.aamc.org/students/medstudents/cim/

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    [bahy-ol-uh-jee]

    ● Bio = life !

    ● ...ology = the study of !

    ● Biology is the science that studies life

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    The Scientific Method in Action

    ● A systematic way of gaining information

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    The Scientific Method: Observation

    ● An observation is a thoughtful and careful recognition of an event or a fact. !

    ● The careful observation of a phenomenon leads to a question. – How does this happen? – What causes it to occur?

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    The Scientific Method: The Hypothesis

    ● Hypothesizing – question an observation – propose possible solutions to questions based on what

    is already understood about the phenomenon ● Hypotheses must:

    – be logical – account for all current information – make the least possible assumptions – be testable

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    Testing Hypotheses

    ● Hypotheses need to be tested to see if they are supported or disproved. – Disproved hypotheses are rejected – Hypotheses can be supported but not proven !

    ● Ways to test a hypothesis: – Gathering relevant historical information

    ● Retrospective Studies – Make additional observations from the natural world – Experimentation

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    The Scientific Method: Experimentation

    ● Experiments – rigorous tests to determine if the solutions are supported !

    ● Experiments attempt to recreation an occurrence – tests whether or not the hypothesis can be supported or

    rejected !

    ● There are many types of experiments – laboratory, clinical trials, surveys, statistical analyses

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    Experimental Design

    ● All experiments have key elements in common: !

    – Experiments must be controlled ● this means that all aspects except for one variable must be kept

    constant ● usually include any two groups.

    – Experimental group: variable is altered, independent variable – Control group: variable is not altered, dependent variable !

    – Experiments use models to recreate occurrences, but in a controlled setting ● model organisms, ISS, cohorts

    http://news.bbc.co.uk/2/hi/health/1949073.stmhttp://www.nasa.gov/mission_pages/station/main/index.html

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    Experimental Design

    ● Experiments must: – use large numbers of subjects and/or must be

    repeated several times (replication) – be independently reproducible !

    ● The validity of experimental results must: – be tested statistically

    ● chi-squared test for statistical significance – be scrutinized by other scientists

    ● peer reviewed

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    Theory

    ● If the hypothesis is supported by ample experimental data, it leads to a theory.

    ● A theory may be defined as a widely accepted, plausible general statement about a fundamental concept in science.

    – The germ theory states that infectious diseases are caused by microorganisms. ● Many diseases are not caused by microorganisms, so we must be

    careful not to generalize theories too broadly. – Theories continue to be tested

    ● Exceptions identified ● Modifications made

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    A Scientific Law

    ● A scientific law is a uniform and constant fact of nature that describes what happens in nature.

    – An example: All living things come from pre-existing living things. ● Scientific laws promote the process of generalization.

    – Inductive reasoning – Since every bird that has been studied lays eggs, we can generalize

    that all birds lay eggs. ● Once a theory becomes established, it can be used to

    predict specific facts. – Deductive reasoning – We can predict that a newly discovered bird species will lay eggs.

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    Scientific Communication

    ● Data is shared with the scientific community through research articles published in scientific journals.

    – peer review !● Scientists present preliminary

    data at conferences. !● Scientists collaborate directly by

    phone and 
e-mail.

    http://www.washingtonpost.com/wp-dyn/content/article/2009/11/21/AR2009112102186.html

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    A Sample Experiment

    Scientific American August 2010

    http://www.lscc.edu/faculty/christopher_c_leibner/BSC%2525201005/Forms/AllItems.aspx

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    A Sample Experiment

    ● Article: Hardt, Marah J. and Safina, Carl. “Threatening Ocean Life from the Inside Out.” Scientific American August 2010: Vol. 303 2. !

    ● What types of observations were being made? ● State a hypothesis that was tested. ● Describe an experiment that was conducted. ● Discuss a variable that was studied and describe how constants

    where maintained in the experiment. ● How was a model system was used to simulate the conditions being

    studied. ● How were the complex processes being studied reduced to their

    simplest parts? ● What was learned from the experiments?

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    The Science of BiologyChapter 1

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    1.1 The Science of Life

    • Biology unifies much of natural life !

    • Biology attempts to define life !

    • Biology Living reveals a hierarchical organization of living systems

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    How do we know that something is alive?

    breathing pale pulse

    breathing pulse !

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    How do we know that something is alive?

    » Leewenhock *all living things are made of cells !*reproduce *create waste *respond to the environment *evolves

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    Levels of Organization

    CELLTISSUE

    ORGAN

    ORGAN systemorganism

    community

    ecosystem BIOSPHERE

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    DARWIN AND EVOLUTION

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    Natural Selection

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    the Galapagos

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    Voyage of the Beagle

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    Exit Ticket 6/13/16

    » What is biology? !

    » How do we know when something is alive? !

    » Who is Darwin? Why is his name remembered?

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    Charles Darwin

    • Evolution: Modification of a species over generations

    • “descent with modification” !

    • Natural Selection: Individuals with superior physical or behavioral characteristics are more likely to survive and reproduce than those without such characteristics

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    Darwin’s Evidence

    • Similarity of related species • Darwin noticed variations in related species living in different locations

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    1.4 Unifying Themes in Biology

    Cell theory • The cell theory describes the organization of

    living systems • All living organisms are made of cells, and all

    living cells come from preexisting cells

  • Fig. 1.11a

    Single Celled Organisms

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  • Fig. 1.11b

    Multi-Cellular Organisms

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    1.4 Unifying Themes in Biology

    Molecular basis of inheritance • The molecular basis of inheritance explains

    the continuity of life • DNA encodes genes which control living

    organisms and are passed from one generation to the next

    • The DNA code is similar for all organisms (The Central Dogma)

  • Fig. 1.12

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    Unifying Themes in BiologyStructure and Function • The proper function of a molecule is

    dependent on its structure • The structure of a molecule can often tell

    us about its function • Four major classes of Biomolecules

    1. Nucleic Acids 2. Amino Acids 3. Lipids 4. Carbohydrates

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    Unifying Themes in BiologyEvolutionary Change • The diversity of life arises by evolutionary

    change leading to the present biodiversity we see

    • Biology attempts to classify life’s great diversity based on these unifying themes

    • Currently all living things are classified into 3 Domains subdivided into Kingdoms (more on taxonomy to come)

    • This process is always changing

  • Fig. 1.13

    The Diversity of Life

    Three Domains: 1. Eukarya 2. Archaea 3. Bacteria

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  • Fig. 1.13-1

    Domain Eukarya is Divided into four Kingdoms: 1. Plantae 2. Fungi 3. Animalia 4. Protista

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  • Fig. 1.13-2

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  • Fig. 1.13-3

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    Unifying Themes in Biology

    Evolutionary Conservation • Evolutionary conservation explains the unity

    of living systems • The underlying unity of biochemistry and

    genetics argues that all life has evolved from the same origin event

    • Critical characteristics of early organisms are conserved and passed on to future generations

  • Fig. 1.14

    Homeodomains

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    Unifying Themes in Biology

    Cells are information-processing systems • Every cell in an organism carries the same

    genetic information • The control of gene expression allows cells

    to differentiate into different cell and tissue types

    • Cells also process information received from the environment and respond to maintain homeostasis

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    Unifying Themes in Biology

    Emergent properties • New properties are present at one level of

    organization that are not seen in the previous level

    • The whole is greater than the sum of its parts

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    The Science of BiologyEnd Chapter 1