Ch.1.4: CHARACTERISTICS OF LIFE

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Ch.1.4 CHARACTERISTICS OF LIFE

• In order to be considered LIVING an organism must
  meet
• all 8 of the following criteria
• 1. Made of cells, at least one
• 2. Take in and use energy, do work, produce waste
• 3. Respond to their environment
• 4. Grow, develop and die
• 5. Be highly organized
• 6. Maintain homeostasis
• 7. Heredity contain DNA
• Be able to reproduce at least cells, and
  eventually organisms using the directions in the
  DNA
• DNA is able to change and these changes allow
  populations to evolve

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Made of cells

• Cell Theory says that
• Cells are the basic structural and functional
  units of life
• All organisms have at least one cell
• Cells only come from pre-existing cells
• Cells must have at least
• 1. cell membrane (defining boundary keep things
  inside)
• 2. cytoplasm (material inside cell)
• 3. genetic material (DNA in the form of a
  chromosome)
• 4. free ribosomes ( to make proteins for the
  cell)
• Viruses are less than a cell
• Multicellular organisms vs. unicellular organisms
• Prokaryotic cells vs. Eukaryotic cells
• Plant cells vs. Animal cells vs. Bacteria cells

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Cell Types

• PROKARYOTIC CELLS
• Pro/pre/ before
• karyo center or kernel
• CM, cytoplasm, DNA and free ribosomes
• Bacteria
• Must be single cell
• No nucleus
• 1 chromosome
• No nuclear membrane around chromosome
• No organelles that are made of membranes no
  internal membrane structures or compartments
  including no nucleus/nuclear membrane
• May have cell wall

• EUKARYOTIC CELLS
• eu true
• karyo center or kernel
• CM, cytoplasm, DNA and free ribosomes
• Plants, Animals, Fungi and Protista
• Can be found in single celled organisms (mildew
  and algae) can be found in multicellular
  organisms (people 30 trillion)
• Nucleus made of nuclear membrane to keep in the
  many chromosomes
• Lots of membrane bound organelles that make
  compartments like endoplasmic reticulum and
  vacuoles and mitochondria
• Some have a cell wall

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Take in energy

• Maintaining life requires constant energy
• Photosynthesis provides energy for food web
  (solar energy becomes chemical energy when
  trapped and stored as sugar)
• Autotrophic plants make their own food
• Heterotrophic organisms must eat
• Waste is given off CO2, NH4 and heat , sweat,
  urine/feces, even oxygen (plants)
• Energy is used to do WORK

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Respond

• Respond means react
• Immediate and short term compared to adaptations
• Senses
• Stimuli something that an organism respond to
• Examples groan when alarm clock rings, stomach
  growls when hungry, dog growls when upset,
  hibernate when cold, grow toward the sunlight,
  shiver when cold, laugh, sweat during a test,
  make adrenaline when afraid..

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Grow, Develop and Die

• Growth indicates an increase in size, bigger
  organisms and/or bigger cells could be more
  cells
• Development refers to changes in structure and
  function.
• Baby -gt toddler -gt teen -gt adult -gt elderly.
• Also changes such as metamorphosis
• Senescence means to age.
• Living mortal, wont live forever. Even things
  with long life spans (redwood tree 800 -2000
  years, still eventually die)

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Highly Organized

• Adult human has 30 trillion cells
• They arent just in a pile, and you wouldnt work
  well as one big 120 pound cell!
• Cells are highly organized internally by cell
  membrane, organelles, DNA , etc.
• Organisms are also highly organized with cells ?
  tissues ? organs ? organ systems and then
  organisms
• Unicellular organisms are also highly organized.

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Homeostasis

• Process of maintaining a steady internal state
  while the external environment changes
• Homeo same
• Stasis steady together the same, steady
  state
• Body temp, blood glucose level, hydration, etc.
• Requires a constant input of energy.
• 1000 Cal a day to stay alive of the 2000-2500
  need by an adult human.

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Heredity (Heritable Information )Reproduction

• Cells wear out and need to be replaced
• Skin cells reproduce, asexually, to make more
  skin cells
• Asexual means one source of DNA (one parent) one
  skin cell divides and there are 2 new skin cells
• Organisms will grow develop and die have to
  make next generation or their species will be
  extinct
• Reproduce more individuals by asexual
  reproduction or make reproductive cells (egg/
  sperm/pollen/spores) to be used in sexual
  reproduction (potential new organisms not every
  acorn will be a tree)

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Heredity (Heritable Information)Evolve
(sometimes called Adapt)

• The gene pool of a population changes over long
  periods of time. (7-10 generations)
• This is genetic, not nervous, endocrine, etc.
• This is much slower and longer lasting than
  responses
• Impacts populations (genes available) NOT
  individuals
• Incorporated into the structure of DNA is its
  amazing ability to be replicated accurately AND
  the ability to change and to pass on the new
  version to the next generation.
• Process driven by Natural Selection
• (if you have genes for more successful traits
  at that time, in that setting, then you will have
  offspring that will be successful at leaving
  offspring. If environment changes then
  successful traits will also change)

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