Ten Themes in Study of Life

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Chapter 1

• Ten Themes in Study of Life

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Hierarchy of Organization

• Each level builds on levels below it
• Atoms building blocks of all matter
• Molecules
• Organelles parts of a cell
• Cells smallest unit of life
• Tissues groups of cells acting as one
• Organs groups of tissues acting as one
• Organ systems
• Organism

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Hierarchy beyond Organism

• Population group of same organisms in a defined
  area
• Community group of different species in same
  area
• Ecosystem non-living and living interactions
• Biosphere all ecosystems together
• Portion of the earth which contains living
  organims

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1st Theme Emergent Properties

• Each level new properties emerge
• Head nor handle of a hammer are useful until they
  are together
• Whole is greater than the sum of the parts

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2nd Theme The Cell

• Cell Theory
• Hookes discovery of cork cells 1665
• Leeuwenhoek discovered single celled organisms in
  pond water
• Later saw Blood and Sperm cells
• Schleiden and Schwann developed Cell Theory which
  postulates
• All living things consist of cells
• All cells arise from preexisting cells

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Properties of Living Things

• 1. Order all other characteristics arise due to
  complexity of life

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Properties of Life

• 2. Reproduction life comes from life

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Properties of Life

• 3. Growth and Development heritable programs in
  DNA direct growth
• 4. Energy utilization organisms take in energy
  and transform it to do work

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Properties of Life

• 5. Respond to Stimuli organisms react to
  changes in environment
• 6. Homeostasis maintaining the complexity of
  life

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Properties of Life

• 7. Evolutionary Adaptation populations (key
  term) changes to suit environment

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Cell Types

• All cells contain
• Membrane regulates passage of materials into
  and out of cell
• DNA heritable material that directs many cell
  activities
• Prokaryotic Cells before nucleus
• Do not contain membrane enclosed organelles
• Eukaryotic Cells true nucleus
• Contain organized and complex organelles
• Membrane bound organelles

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3rd Theme Heritable Information

• Order implies information
• Instructions are required to arrange parts or
  processes
• Instructions are encoded into DNA
  (deoxyribonucleic acid)
  
  
  
  
  

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DNA

• DNA is arranged into two long chains called a
  double helix
• Each chain contains a series of 4 chemical
  building blocks called nucleotides
• These are the alphabet of DNA

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DNA cont.

• All forms of life employ same genetic code
• Differences reflect different nucleotide
  sequences
• All forms of life pass on their own set of
  genetic code
• DNA is a heritable molecule
• You get one set of instructions from your Mom and
  one from your Dad

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DNA cont.

• Library of genetic instructions is called the
  Genome
• Each cell contains the entire genome of the
  species
• Humans 3 billion chemical letters long

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4th Theme Structure and Function

• How a device works is correlated to its structure
  Form fits function

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5th Theme Interaction with Environment

• Organisms interact with living and nonliving
  components of ecosystem
• Ecosystem Dynamics
• Nutrient cycles
• Energy flow
• Energy Conversion
• Energy must be transformed from one form to
  another in order to be useful

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6th Theme Regulation

• Work requires workers
• Proteins and enzymes are workhorses of cells
• Enzymes catalyze reactions (speed up normally
  occurring chemical processes)
• These have to be regulated

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Feedback Cycles
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7th Theme Unity and Diversity

• Diversity 1.5 million species identified
• Between 5 to 30 million undiscovered

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Grouping Species

• Taxonomy placing diverse organisms into smaller
  more manageable groups

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Three Domains of Life

• Old thinking all organisms belong in 5 kingdoms
  (Monera, Protista, Fungi, Plantae, Animalia)
• Three major groups of Life New thinking
• Bacteria
• Archaea
• Eukarya

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Unity in the midst of Diversity

• Even diverse organisms contain unifying traits
• DNA is common to all 5 kingdoms
• Eukaryotic cells contain many of the same
  organelles
• Above cellular level all organisms become
  increasingly diversified

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8th Theme Evolution

• Core theme of Biology
• All organisms can be traced back to a common
  ancestor
• Brown Bear and Polar Bear (recent common
  ancestor)
• Brown Bear and Humans (not so recent ancestor,
  typical mammalian ancestor)
• Brown Bear and Retiles (ancient ancestor)
• Ever branching tree of life

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The Origin of Species

• Charles Darwin published The Origin of Species in
  1859
• Argues species arose from a succession of
  ancestors through descent with modification
• The most important facet was How life evolves
• Through natural selection

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Natural Selection

• Observation 1 Individual variation
• Observation 2 Struggle for existence
• Inference Differential reproductive success

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Natural Selection

• Not a trait of individuals, however it is a trait
  of populations
• What does this mean?

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9th Theme Scientific Inquiry

• Scientist strive to understand how things work
• Seek natural causes for natural phenomena
• Scientist use the Scientific method to answer
  questions posed in relation to observations

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Theories in Science

• Theories are not facts, but are testable ideas
  supported by mountains of evidence
• Difference between hypothesis and theory
• Hypothesis Feeding preferences of predators
  cause life history differences in guppy
  populations
• Theory Populations can evolve by natural
  selection because of feeding preferences of
  predators

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10th Theme Science, Technology, and Society

• Watson and Cricks discovery of DNA led to many
  advances in Science
• Manipulation of DNA
• Gene research
• Pharmaceutical companies use genetic research to
  fine tune medications
• One advance leads to another, and another, and so
  on.