Chapter 2: Biology as a Science

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Chapter 2Biology as a Science
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• Characteristics of Living Things

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• Living things are made up of cells
• Most cells perform all the functions we associate
  with life
• Two types of organisms
• Unicellular
• Single celled organism (bacteria, protists)
• Multicellular
• More than one celled Organisms
• Cells are never formed by non-living things

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• Living things are made up of cells
• Multicellular
• Organisms with many cells (humans, dogs)
• Cells are never formed by non-living things

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• Living things reproduce
• Reproduce produce new organisms of the same type
• Sexual reproduction
• Requires 2 cells from different individuals to
  unite to produce the first cell of a new organism
• Asexual reproduction
• Single organism can reproduce without the aid of
  another-splits in two

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• Living things grow and develop
• Example an acorn when it sprouts
• Development cycle of change
• We all go through some cycle of change (infant to
  toddler, toddler to a young child, young child to
  a teen, teen to an adult, adult to the elderly
  stage)

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• Living things obtain and use energy
• Metabolism sum of all chemical reactions in the
  body-a balance of anabolism and catabolism

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• Living things obtain and use energy
• Living things obtain energy from their
  surroundings and use that energy to grow,
  develop, and reproduce.
• Example plants get energy from sunlight
• Example animals get energy from food

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• Living things obtain and use energy
• Catabolism breakdown of complex substances into
  simpler ones
• Example digestion
• Anabolism any process in a living thing that
  involves building complex substances from simpler
  substances
• Example photosynthesis

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• Living things respond to their environment
• Stimulus anything that causes an organism to
  react triggers a response
• Examples light, temp., odor, sound, gravity,
  heat
• Irritability the ability to react to a stimulus
• Example plant stems grow away from pull of
  gravity

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THE PROCESS BY WHICH ORGANISMS RESPOND TO
STIMULI IN WAYS THAT KEEP CONDITIONS IN THEIR
BODY SUITABLE FOR LIFE IS CALLED HOMEOSTASIS
HOMEOSTASIS
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HOMEOSTASIS

• The ability of an organism to maintain constant
  or stable conditions that are necessary for life.
• Example your body has a thermostat. When you
  get too hot, you sweat and cool off. If you
  sweat for awhile you will tend to get thirsty and
  then you drink fluids to replace the water that
  you lost while sweating.

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Quiz

1. What are the characteristics of life?

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Quiz-Answers

1. Living things are made up of cells
2. Living things reproduce
3. Living things grow and develop
4. Living things obtain and use energy
5. Living things respond to their environment
6. Living things maintain HOMEOSTASIS

1. Cellular organization
2. Reproduction
3. Metabolism
4. Homeostasis
5. Heredity
6. Responsiveness
7. Growth and Development

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Branches of Science

• Molecular Level
• Biochemistry
• Cellular Level
• Cytology
• Microbiology
• Multicellular
• Zoology
• Botany

• Population
• Ecology
• Global
• Biosphere

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Branches of Science

• Genetics - the study of genes and heredity.
  Herpetology - the study of reptiles (and
  amphibians?)Histology - The study of cells and
  tissue, a microscopic branch of
  anatomy.Ichthyology - the study of
  fishMacrobiology - the study of biology on the
  level of the macroscopic individual (plant,
  animal, or other living being) as a complete
  unit.Mammology - the study of mammalsMarine
  Biology - the study of ocean ecosystems, plants,
  animals, and other living beings.Medicine - the
  study of the human body in health and disease,
  with allopathic medicine focusing on alleviating
  or curing the body from states of
  diseaseMicrobiology - the study of microscopic
  organisms (microorganisms) and their interactions
  with other living thingsMolecular Biology - the
  study of biology and biological functions at the
  molecular level, some cross over with
  biochemistry

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Branches of Science

• Oceanography - the study of the ocean, including
  ocean life, environment, geography, weather, and
  other aspects influencing the ocean. See Marine
  BiologyOrnithology - the study of
  birdsPaleontology - the study of fossils and
  sometimes geographic evidence of prehistoric
  lifePathobiology or pathology - the study of
  diseases, and the causes, processes, nature, and
  development of diseaseParisitology - the study
  of parasites and parasitismPharmacology - the
  study and practical application of preparation,
  use, and effects of drugs and synthetic
  medicines. Physiology - the study of the
  functioning of living organisms and the organs
  and parts of living organismsPhytopathology -
  the study of plant diseasesVirology - the study
  of viruses and some other virus-like agents,
  usually considered part of microbiology or
  pathology Zoology - the study of animals and
  animal life, including classification,
  physiology, development, and behavior (See also
  Entomology, Ethology, Herpetology, Ichthyology,
  Mammology, Ornithology

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Branches of Science

• Agriculture - study of producing crops from the
  land, with an emphasis on practical
  applicationsAnatomy - the study of the animal
  form, with an emphasis on human
  bodiesBiochemistry - the study of the chemical
  reactions required for life to exist and
  function, usually a focus on the cellular
  levelBioengineering - the study of biology
  through the means of engineering with an emphasis
  on applied knowledge and especially related to
  biotechnology.Biomathematics or Mathematical
  Biology - the study of biological processes
  through mathematics, with an emphasis on
  modeling.Biomechanics - often considered a
  branch of medicine, the study of the mechanics of
  living beings, with an emphasis on applied use
  through artificial limbs, etc.Biophysics - the
  study of biological processes through physics, by
  applying the theories and methods traditionally
  used in the physical sciencesCell Biology - the
  study of the cell as a complete unit, and the
  molecular and chemical interactions that occur
  within a living cell.Cryobiology - the study of
  the effects of lower than normally preferred
  temperatures on living beings.

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Tools of a Biologist

• To study small organisms, researchers have
  developed several kinds of microscopes.
• Microscopes are instruments that produce
  larger-than-life images, pictures, and even
  videotapes.

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Tools of a Biologist

• Compound light microscope uses light and
  multiple lenses to magnify an object
• Can observe cells and singled-celled organisms
  while they are still alive

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The Compound Microscope
Eyepiece
Coarse focus
Fine focus
Objective lens
Stage
Diaphragm
Light Source
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Tools of a Biologist

• Electron microscopes use electrons instead of
  light to get up to 1000x finer detail.
• Transmission electron microscope requires thin
  samples images look flat
• Scanning electron microscope produces dramatic
  3-D pictures

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Techniques Used By a Biologist

• Centrifugation- separation of cell parts
• Microdissection-dissection or removal of cell
  parts while under the microscope
• Cell cultures- used to obtain identical cells
  desired to study
• These are just some of the techniques used in the
  Lab

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• It is also very important to remember that you
  are working with materials that are harmful to
  your body and that you should not touch your
  nose, ear or mouth (including eating and
  drinking) until you have thoroughly washed your
  hands.