biology in the 21 st century
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Biology in the 21 st Century. Biological Questions. Gana. Gana. What is science?. Science is… The continual effort to discover and increase human understanding of how reality works .

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what is science
What is science?
  • Science is…
    • The continual effort to discover and increase human understanding of how reality works.
      • The systematic process allows us to better understand past events and predict future events of a similar kind.
        • Science is not static, it is ever changing.
what do you think
What do you think?
  • Define the following…
    • Fact
    • Hypothesis
    • Law
    • Theory
  • A scientific fact is a controlled, repeatable and/or rigorously verified observation, probability of “truth” is incredibly high—little room for doubt.
    • An example of current facts:
      • All things with mass have gravity.
      • Gravity is an attractive force.
  • Sometimes new discoveries make us have to re-evaluate and/or revise our “facts” – THAT’S SCIENCE!
  • Former Facts
    • There are three states of matter.
    • The Earth is flat.
  • A suggested explanation; a proposal based on reason that predicts a possible correlation between multiple phenomena (incidents, events, observations, etc.)
  • Notes only that something happens, happens consistently and across the universe; usually simply stated; frequently can be stated mathematically.
  • Example:
    • Newtons 2nd Law: F = ma
      • A body of mass (m) subject to a force (F) undergoes an acceleration (a) that has the same direction as the force and a magnitude that is directly proportional to the force and inversely proportional to the mass.
  • Notes why something happens, explains why laws and facts are true, a framework about a class or group of phenomena, sometimes valuable to predict.
    • Theories are never “proven”—they are confirmed by overwhelming data, all theories, like all ideas in science, are subject to correction.
  • Examples:
    • Plate Tectonic Theory
    • Atomic Theory of Matter
    • Germ Theory of Disease
    • Music Theory
    • Gravitational Theory
    • Theory of Molecular Genetics
    • Theory of Natural Selection
diversity of life
Diversity of Life
  • Life is found almost everywhere on earth.
    • There are organisms that live in hydrothermal vents in the deepest part of the ocean, in thousands-of-years-old Antarctic ice.
the biosphere
The Biosphere
  • All living things and all the places they are found on Earth make up the biosphere.
    • Every part of the biosphere is connected to another.
  • The variety of life in the biosphere is biodiversity.
    • Greater biodiversity is usually found near the equator.
      • Why do you think this is?
  • Over 2 million species have been identified, but scientists estimate that tens of millions of species are left to be identified.
    • Every year, biologists discover about 10,000 new species.
characteristics of living things
Characteristics of Living Things
  • Biology is the scientific study of all forms of life, or all types of organisms.
  • An organism is any individual living thing.
    • Which of these is a living thing? Why is it living and the other non-living?
characteristics of living things1
Characteristics of Living Things
  • All living organisms share these characteristics:
    • They are made of cells.
    • They need energy.
    • They respond to their environment.
    • They reproduce and grow.
    • They maintain a stable internal environment.
    • They change over time.
unifying themes
Unifying Themes
  • Biology has several unifying themes:
    • All levels of life have systems of related parts.
    • Structure and function are related in biology.
    • Organisms must maintain homeostasis to survive in diverse environments.
    • Adaptation over time explains the unity and diversity of life.
biology is a process of inquiry
Biology is a Process of Inquiry
  • Scientific thinking begins with observation.
    • Observation uses the senses—hearing, sight, smell, etc.
    • It involves repeatedly recording the information over time.
thinking like a scientist
Thinking Like a Scientist
  • Over time, data is gathered.
    • Qualitative data = descriptions and involves characteristics that can’t usually be counted.
    • Quantitative data = expressed as numbers, obtained by counting or measuring.
thinking like a scientist1
Thinking Like a Scientist
  • From a large amount of data—an Inference is made.
    • An Inference is a logical interpretation of phenomena
    • It is based on prior knowledge or experience.
explaining and interpreting evidence
Explaining and Interpreting Evidence
  • After initial observations—a scientist will from one or more Hypotheses.
  • A hypothesis is:
    • Based on prior knowledge
    • Based on inference
    • Informed
    • Creative and Imaginative
      • Controlled experiments
      • Collecting more data
spontaneous generation
Spontaneous Generation
  • Up until the late 1800’s some people believed that life generated from non-life.
redi s experiment
Redi’s Experiment

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.


Uncovered jars

Covered jars

Controlled Variables:

jars, type of meat,

location, temperature,



days pass

Manipulated Variables:

gauze covering that

keeps flies away from


Responding Variable:

whether maggots


Maggots appear

No maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

spallanzani s experiment
Spallanzani’s Experiment
  • Spallanzani tested Redi’s results with an experiment of his own.

Flask is


Gravy is teeming

with microorganisms.

Gravy is boiled.

Flask is


Gravy is free of


Gravy is boiled.

pasteur s experiment
Pasteur’s Experiment

Broth is boiled.

Broth is free of


for a year.

Curved neck

is removed.

Broth is teeming with microorganisms

modern tools of biology
Modern Tools of Biology
  • Microscopes
  • Medical Imaging
  • Modeling on computers
  • Molecular Genetics
    • The study and manipulation of DNA.
    • Genomics = the study and comparison of genomes within and across species.
biology and your future
Biology and Your Future
  • Food
    • 70-75 % of processed food contains some genetically engineered ingredients.
    • 45% of U.S. corn is genetically engineered.
    • 60% of adults in the U.S. are overweight or obese.
biology and your future1
Biology and Your Future
  • Environment and health
    • Recent studies have indicated that chemicals present in re-used water can cause hormonal deformities in certain plant and animal species.
    • It has been suggested that hormones present in certain meat products can cause children to hit puberty quicker.
biology and your future2
Biology and Your Future
  • Biotechnology
    • Includes the use of microorganisms to make bread and cheese.
    • Used in medicine, agriculture, forensic science, and many other fields.
      • The use of DNA testing in criminal courts is an example of biotechnology.
biology and your future3
Biology and Your Future
  • Transgenic Organisms
    • Organisms that have genes from more than one species, or have altered copies of their own genes are transgenic organisms.
      • Transgenic bacteria is used to create insulin that treats diabetes.
      • Transgenic cows and sheep create antibodies and proteins that humans can use.
      • Transgenic plants are resistant to insects and can reduce or end the need of pesticides.
biology and your future4
Biology and Your Future
  • Genetic Screening
    • These tests can indicate whether individuals or their potential offspring may be at risk for certain diseases or genetic disorders.
      • This can help with early diagnosis and treatment.
    • Who should have access to the information? What genetic quirks should be considered disorders? Could genetic information be used to design children?
science as a way of knowing
Science as a Way of Knowing
  • Science is not a collection of immutable truths.
  • Science is an ongoing process.
  • Scientists need to be skeptical, open minded, and analytical.
  • Science and human values often intersect. The knowledge we collect today affects the lives of people tomorrow.