CHARACTERISTICS OF LIFE

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CHARACTERISTICS OF LIFE

• LIVING THINGS ARE MADE FROM THE SAME BUILDING
  BLOCKS, ORGANIZED INTO CELLS

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LEVELS OF ORGANIZATION

• atoms
• molecules ?nonliving abiotic
• cells ?living biotic
• tissues
• organs
• organism living thing

Human Brain Nerve Cell
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ORGANISM living thing

• Species similar organisms, interbreed in the
  wild, only with each other
• Species reproductively isolated group of
  organisms
• Species one kind of organism

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• population all members of the same species,
  that live together in same area, at same time
• community all populations (plants animals)
  that live together in same area, at same time
• physical environment non living (abiotic)
• air, rocks, soil, water, light, climate
• ecosystem community physical environment
• biosphere all organisms on Earth
• all communities on Earth
• all life on Earth

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CHARACTERISTICS OF LIFE

• 2) ORGANISMS GROW MAINTAIN THEIR ORGANIZATION
  BY GETTING MOLECULES ENERGY FROM THE
  ENVIRONMENT

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• Autotrophs self feeding

plants, algae, some bacteria
Energy Flow Sunlight ? Food Molecules ?
Work ? Heat
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Heterotrophs other feeding (eaters)
animals, fungi, bacteria
Energy Flow Food Molecules ? Work (stay
organized) ? Heat (to atmosphere)
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CHARACTERISTICS OF LIFE

• 3) ORGANISMS MOVE OR OTHERWISE RESPOND TO CHANGES
  (STIMULI) IN THE EXTERNAL ENVIRONMENT
• Response Behavior

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CHARACTERISTICS OF LIFE

• 4) ORGANISMS REPRODUCE
• PASS ON THEIR DNA TO THEIR OFFSPRING
• DNA Instructions

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CHARACTERISTICS OF LIFE

• 5) GROUPS OF ORGANISMS SHOW VARIATIONS EVOLVE,
  OR CHANGE, TO ADAPT TO THEIR ENVIRONMENT
• Source of variations mutations,
• which are changes in DNA
• and new combinations
• created by sexual reproduction

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Evolution changes in a population over time
Natural Selection nature selects the changes
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LIFE MODEL

• Survival
• First Priority for Resources Is Stay Alive
• Growth
• Extra Resources must be available
• Reproduction
• Extra Resources must be available

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Science

• SCIENCE derived from a Latin verb meaning to
  know
• seeks natural causes for natural phenomena
• Includes two forms of inquiry
• 1) Discovery (descriptive) science
• 2) Hypothesis-driven science

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Discovery Science

• Observations of nature
• Human genome project
• Inductive conclusion is a generalization based on
  many specific observations
• Ex. All organisms made of one or more cells

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Hypothesis-driven Science

• Scientific Method series of steps that form a
  formal process of inquiry
• Deductive conclusion is using the general premise
  to predict a specific result
• Follows ifthen logic, i.e. if all organisms
  are made of cells, humans are organisms, then
  humans are made of cells.

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HYPOTHESIS

• Can be shown to be false
• Can NOT be proved true, only supported by
  results
• Example
• I am the fastest runner in the world

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Fly Mimicry Experiment

• OBSERVATIONS
• Jumping Spiders
• stalk and pounce on flies
• 2) wave their legs to scare off other jumping
  spiders

Jumping Spider
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Fly Mimicry Experiment

• OBSERVATIONS
• Spider-mimicking flies
• 1) have markings on their wings that look like
  spiders legs
• 2) wave their wings (false legs) at spiders

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Fly Mimicry Experiment

• QUESTION 1
• Does mimicry (looking like jumping spiders)
  actually turn real jumping spiders away?

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Fly Mimicry Experiment

• HYPOTHESIS
• Mimicry (looking like jumping spiders) does turn
  real jumping spiders away.

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Fly Mimicry Experiment
Control Group (of organisms) Normal
Spider-mimicking flies Experimental or
Treatment Group (of organisms) Flies with wing
markings or legs masked
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Fly Mimicry Experiment

• Manipulated or Independent Variable difference
  between two groups
• that is being tested
• looking like jumping spiders

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Fly Mimicry Experiment

• Dependent Variable results that may be
  different between the two groups being compared
• Dependent Variable Pounce rate ( of trials in
  which spiders jumped on the fly)

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Fly Mimicry Experiment

• Controlled variables or Constants
• all factors that are the same between the two
  groups

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Fly Mimicry Experiment

• Results spiders pounced on treatment group more
  than controls, as shown on graph
• Conclusion the results support the hypothesis
  that mimicry (looking like jumping spiders) did
  turn jumping spiders away

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Fly Mimicry Experiment

• OBSERVATIONS
• Jumping Spiders
• stalk and pounce on flies
• 2) wave their legs to scare off other jumping
  spiders

Jumping Spider
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Fly Mimicry Experiment

• OBSERVATIONS
• Spider-mimicking flies
• 1) have markings on their wings that look like
  spiders legs
• 2) wave their wings (false legs) at spiders

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Fly Mimicry 2nd Experiment

• QUESTION 2
• Are both types of mimicry
• (acting looking like jumping spiders) required
  to turn real jumping spiders away?

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Fly Mimicry 2nd Experiment

• HYPOTHESIS
• Both types of mimicry (acting looking) like
  jumping spiders) are required to turn real
  jumping spiders away.

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Fly Mimicry 2nd Experiment

• Manipulated Variables difference between two
  groups that are being tested
• Mimicry looking like jumping spiders
• wing markings
• Mimicry acting like jumping spiders
• wing waving

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Fly Mimicry 2nd Experiment

• Five Test Groups of Flies
• 1) Normal spider mimics
• 2) Mimics w/ mimic wing transplants
• 3) Mimics w/ housefly wing transplants
• 4) Houseflies w/ mimic wing transplants
• 5) Normal houseflies

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Fly Mimicry 2nd Experiment

• Dependent Variable results that may be
  different between the two groups being compared
• Dependent Variable actual number of stalk and
  attack responses by spiders

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Fly Mimicry 2nd Experiment

• Results spiders stalked and attacked groups
  without both types of mimicry more often than
  groups with both types
• Conclusion the results support the hypothesis
  that both types of mimicry (acting looking like
  jumping spiders) are required to turn jumping
  spiders away

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Scientific Theory
According to the National Academy of
Sciences, Some scientific explanations are so
well established that no new evidence is likely
to alter them. The explanation becomes a
scientific theory. In everyday language a theory
means a hunch or speculation. Not so in science.
In science, the word theory refers to a
comprehensive explanation of an important feature
of nature that is supported by many facts
gathered over time. Theories also allow
scientists to make predictions about as yet
unobserved phenomena.
According to Stephen Hawking, "a theory is a good
theory if it satisfies two requirements It must
accurately describe a large class of observations
on the basis of a model which contains only a few
arbitrary elements, and it must make definite
predictions about the results of future
observations".
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Isaac Newton's theory of universal gravitation is
a physical law describing the gravitational
attraction between bodies with mass. It states
the following Every object attracts every other
object by a force pointing along the line
intersecting both objects. The force is
proportional to the product of the two masses and
inversely proportional to the square of the
distance between the objects. Is it supported
by many facts gathered over time? Does it allow
scientists to make predictions about as yet
unobserved phenomena?