Chapter 1Biology, the Study of Life
Scientific Method• 1. Observation    • Using senses    • Learning from other scientists in the field• 2. Create Hypothesis...
• 3. Experiments and more observations    • Experimental variable       – What is changed in experiment    • Test groups  ...
• 4. Conclusion     •   Is hypothesis supported by data or not     •   If not supported, propose new hypothesis     •   CA...
Observation  Hypothesis  Experiment/  Observation  ConclusionScientific Theory
Sample Experiment – Growing     plants in presence of salt• Observation – Previous research, fields irrigated  with saltwa...
• Results                                        Average Growth of Plants watered                                         ...
• Conclusion – Hypothesis is supported.  Data illustrates that as salt concentration of  water increased, plant growth dec...
• Follow-up Results                                             Average Growth of Plants watered                          ...
• Follow-up Conclusion – Possible that  different plants are affected in different  ways when exposed to salt. Native  env...
Five Basic Theories of Biology   Theory                              Concept• Cell          •   All organisms are composed...
Levels of Biological Organization• Atom   – Smallest unit of an element (protons, electrons, neutrons)• Molecule   – Two o...
• Organism  – Individual complex individual containing organ    systems• Population  – Organisms of same species in partic...
Cells are the Fundamental Unit of            Living Things• Cell Theory  – Cells are the fundamental unit of living things...
Organisms have a Genetic         Inheritance• Gregor Mendel  – Father of genetics  – Performed experiments with pea plants...
• Gene Theory  – Genes are hereditary units composed of DNA  – Genes control the structure and function of    cells and or...
Organisms Regulate their Internal          Environment• Theory of Homeostasis  – Cells and organisms have an internal    e...
• Response to stimuli – this ability assists  the homeostatic ability of organism  – Vulture detecting carcass     • For f...
The Biosphere is Divided into           Ecosystems• Theory of Ecosystems  – Organisms form units in which they interact   ...
• Ecosystems characterized by  – Chemical cycling    • Chemicals move from one population to another in      a food chain ...
The Ancestry of Species can be           Determined• Theory of Evolution   – Organisms have shared characteristics due to ...
Evolutionary Relationships help   Biologists Group Organisms• Organizing Diversity  – Taxonomy     • Identifying and group...
• Domains – 3 domains  – Archaea    • Live in harsh environments    • Prokaryotes  – Bacteria    • Live in more common    ...
• Scientific Names  – Binomial nomenclature    •   2 part name    •   Genus and specific epithet (descriptive term)    •  ...
Evolution through Natural Selection Results     in Adaptation to the Environment• Charles Darwin  – Father of evolution  –...
Plant typically producessmooth leavesMutation causes leavesto be covered with hairsDeer prefer to eatsmooth leavesHairy le...
Evolution’s Many Applications• Agriculture  – Artificial selection of crops and livestock for high yield    in a short amo...
Evolution from a Common AncestorAccounts for the Characteristics of Life1.   Life is organized2.   Life uses materials and...
Bio 100 Chapter 1
Bio 100 Chapter 1
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Bio 100 Chapter 1

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Explains the scientific method, how to use it, and biological theories that we will be discussing throughout the semester.

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Bio 100 Chapter 1

  1. 1. Chapter 1Biology, the Study of Life
  2. 2. Scientific Method• 1. Observation • Using senses • Learning from other scientists in the field• 2. Create Hypothesis • Based on existing knowledge • If not supported, it can be – Modified – Rejected • Must be testable – Morals and religious beliefs are not always testable
  3. 3. • 3. Experiments and more observations • Experimental variable – What is changed in experiment • Test groups – Exposed to experimental variable • Control group – Not exposed to experimental variable • Model – Sometimes used in place of actual object » Computer software » Mice instead of humans • Data – Results of experiments and observations – Correlation does not indicate causation
  4. 4. • 4. Conclusion • Is hypothesis supported by data or not • If not supported, propose new hypothesis • CANNOT prove anything in science, only support • Experiments and observations must be repeatable by other scientists• Scientific Theory • Ultimate goal of science • Accepted explanations for how the world works
  5. 5. Observation Hypothesis Experiment/ Observation ConclusionScientific Theory
  6. 6. Sample Experiment – Growing plants in presence of salt• Observation – Previous research, fields irrigated with saltwater are lifeless• Hypothesis – As the concentration of salt in the soil increases, the amount of plant growth will decrease• Experiment – Include replicates Control Pots Test Pots I Test Pots II Water Only 5% Saltwater 10% Saltwater
  7. 7. • Results Average Growth of Plants watered with Varying Salt Concentrations 25 20 15 10 5 0 h wo G na P ega ev A Control 5% Saltwater 10% Saltwater r Treatment t r t l
  8. 8. • Conclusion – Hypothesis is supported. Data illustrates that as salt concentration of water increased, plant growth decreased.• Follow-up Experiment – Perform the same experiment with plants that live along the ocean shore.
  9. 9. • Follow-up Results Average Growth of Plants watered with Varying Salt Concentrations 25 Average Plant Growth (mm) 20 15 10 5 0 Control 5% Saltwater 10% Saltwater Treatment
  10. 10. • Follow-up Conclusion – Possible that different plants are affected in different ways when exposed to salt. Native environment may play a large role.
  11. 11. Five Basic Theories of Biology Theory Concept• Cell • All organisms are composed of cells, and new cells only come from preexisting cells• Gene • All organisms contain coded information that dictates their form, function, and behavior • All organisms have a common ancestor, but• Evolution each is adapted to a particular way of life • All organisms have an internal environment• Homeostasis that must stay relatively constant within a range protective of life • All organisms are members of populations• Ecosystem that interact with each other and with the physical environment within a particular locale
  12. 12. Levels of Biological Organization• Atom – Smallest unit of an element (protons, electrons, neutrons)• Molecule – Two or more atoms of same or different elements• Cell – Structural and functional unit of all living things• Tissue – Group of cells with a common structure and function• Organ – Tissues functioning together for a specific purpose• Organ System – Several organs working together
  13. 13. • Organism – Individual complex individual containing organ systems• Population – Organisms of same species in particular area• Community – Interacting populations in a particular area• Ecosystem – Community plus physical environment• Biosphere – Crust, water, and atmosphere inhabited by living things
  14. 14. Cells are the Fundamental Unit of Living Things• Cell Theory – Cells are the fundamental unit of living things – Cells come from other cells • Split • Sexual reproduction – Cells use materials and energy • Sun is the ultimate source of energy – allows plants to grow, which provides animals with food
  15. 15. Organisms have a Genetic Inheritance• Gregor Mendel – Father of genetics – Performed experiments with pea plants and inheritance – Genes – units of heredity• James Watson and Francis Crick – Genes are composed of DNA
  16. 16. • Gene Theory – Genes are hereditary units composed of DNA – Genes control the structure and function of cells and organisms• Gene theory applications – Study metabolism at molecular level – Who is related to whom – Species conservation – Genetic testing for diseases
  17. 17. Organisms Regulate their Internal Environment• Theory of Homeostasis – Cells and organisms have an internal environment – Cells regulate this environment so that it stays fairly constant• Examples – Body maintaining blood sugar levels – Reptiles using sun to regulate temperature – Plants bending towards sunlight
  18. 18. • Response to stimuli – this ability assists the homeostatic ability of organism – Vulture detecting carcass • For food – Monarch butterfly sensing fall • Time to migrate – Plant bending towards sun • For photosynthesis – Animal running away from danger • For survival
  19. 19. The Biosphere is Divided into Ecosystems• Theory of Ecosystems – Organisms form units in which they interact with the biotic (living) and abiotic (nonliving) components of the environment• Biosphere – Climate (temperature and precipitation) determines where ecosystems are found in biosphere
  20. 20. • Ecosystems characterized by – Chemical cycling • Chemicals move from one population to another in a food chain • Death and decomposition return nutrients back to the soil to be used by plants again – Energy flow • From sun to plants to other members of the food chain • Gradually dissipates, does not cycle • Photosynthesizers required to absorb energy
  21. 21. The Ancestry of Species can be Determined• Theory of Evolution – Organisms have shared characteristics due to common descent – Evolutionary tree • Traces the ancestry of a group to a common ancestor – Ways to trace evolution • Molecular data • Fossil record • Anatomy and physiology of organism • Embryonic development of organismRemember: species evolve,not individuals
  22. 22. Evolutionary Relationships help Biologists Group Organisms• Organizing Diversity – Taxonomy • Identifying and grouping organisms according to certain rules – Classification categories • Least inclusive to most inclusive • Species, genus, family, order, class, phylum, kingdom, and domain
  23. 23. • Domains – 3 domains – Archaea • Live in harsh environments • Prokaryotes – Bacteria • Live in more common environments • Prokaryotes – Eukarya • Eukaryotes • Protists, fungi, plants, and animals
  24. 24. • Scientific Names – Binomial nomenclature • 2 part name • Genus and specific epithet (descriptive term) • Phoradendron tomentosum or P. tomentosum • Scientific names are Latin and universally used to avoid confusion
  25. 25. Evolution through Natural Selection Results in Adaptation to the Environment• Charles Darwin – Father of evolution – Concluded that natural selection is the process that makes modification (adaptation) possible• Natural selection – Some aspects of the environment selects which traits are more apt to be passed on to the next generation – Mutations fuel natural selection because they produce variation
  26. 26. Plant typically producessmooth leavesMutation causes leavesto be covered with hairsDeer prefer to eatsmooth leavesHairy leaves have anadvantageGenerations later, mostof those plants producehairy leaves
  27. 27. Evolution’s Many Applications• Agriculture – Artificial selection of crops and livestock for high yield in a short amount of time – Pesticide use selects for resistant insects• Medicine – Antibiotic use selects for resistant bacteria• Conservation – Bacteria converting corn to ethanol, select for most efficient – Endangered species breeding
  28. 28. Evolution from a Common AncestorAccounts for the Characteristics of Life1. Life is organized2. Life uses materials and energy3. Life reproduces4. Life is homeostatic5. Life responds to stimuli6. Life forms ecosystems7. Life evolves

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