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Unit One


Unit One An Introduction to Environmental Science Reasons for and Purpose of Environmental Science Environment sum total of one s surroundings; two ... – PowerPoint PPT presentation

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Title: Unit One

Unit One
  • An Introduction to Environmental Science

Reasons for and Purpose of Environmental Science
  • Environment sum total of ones surroundings
    two categories that compose surroundings
  • Biotic Factors living organisms both plant
    (flora) and animal (fauna)
  • Abiotic Factors nonliving things such as water,
    air, and soil

Reasons for and Purpose of Environmental Science
  • Environmental Science studies how the natural
    world functions and the specific interactions
    between humans ( Homo sapiens) and their
  • It is highly interdisciplinary and incorporates
    subjects such as biology, ecology, geology,
    meteorology, oceanography, limnology, sociology,
    and public policy.

Reasons for and Purpose of Environmental Science
  • If humans did not negatively impact the natural
    world, there would most likely not be the
    discipline of Environmental Science
  • The negative impact arises out of overuse and
    pollution of the natural world
  • Resources various substances found in nature
    that are needed for survival and comfort

Reasons for and Purpose of Environmental Science
  • Two types of resources
  • Renewable resources unlimited supply assuming
    wise use (these resources are usually biotic)
  • Example
  • Nonrenewable resources limited supply (these
    resources are abiotic)
  • Example

Reasons for and Purpose of Environmental Science
  • The goal of an environmental scientist is to
    learn more about how humans interact with their
    surroundings from an objective and fact based
  • Environmental Science is not the same as
  • Environmentalism is a social movement dedicated
    to the preservation of the natural world this
    movement began in the early 1970s with the
    celebration of the 1st Earth Day

The Science behind Environmental Science
  • In order to properly conduct scientific research
    of any kind the scientific method must be
  • There are 5 steps to this method
  • What are the steps?
  • 1) State problem
  • 2) Formulate hypothesis
  • 3) Experiment
  • 4) Analyze results
  • 5) Conclusion

The Science behind Environmental Science contd
  • When research/experiments are conducted,
    quantitative data and not qualitative data must
    be collected
  • The collection of quantitative data allows the
    scientist to remain objective in the reporting of
    his/her data
  • Quantitative Objective
  • Qualitative Subjective

The Science behind Environmental Science contd
  • Bias should be avoided
  • Control(s) should be used in experiments for the
    purpose of comparison
  • Variables that would negatively affect results of
    an experiment should be eliminated
  • Independent variable variable scientist
    manipulates (example time)
  • Dependent variable its outcome depends on
    independent variable (example temperature)
  • http//www.biologycorner.com/worksheets/controls.h

Data should be plotted on a graph
The Science behind Environmental Science contd
  • Step 2 of Scientific Method requires one to form
    a hypothesis a.k.a. educated guess
  • Step 5 of Scientific Method requires one to
    support or not support the hypothesis made in
    step 2 based on data obtained in step 3
  • If experiment is deemed worth by peers it can be
    published in one of numerous scientific journals
    for the purpose of disseminating

Unfortunate Reality in Science
  • One in seven scientists say they are aware of
    colleagues that have invented results
  • Dishonesty and misrepresentation are widespread
    due to several factors
  • Inherent bias
  • Professional pressure
  • Monetary gain
  • One in Seven Scientists Say Colleagues Fake
    Data in The Times June 5th, 2009

The Science behind Environmental Science contd
  • Theory - statement based on a large supporting
    body of evidence is more accepted in scientific
    community than a hypothesis
  • Evolution
  • Law scientific fact
  • For every action there is an equal and opposite

Current State of Affairs
  • Is our planet healthy? Are we having a net
    negative impact on the Earth?
  • The above questions will be addressed throughout
    the semester

Unit One Biology Basics
  • Evolution, Biodiversity, and Population Ecology

Concepts surrounding Evolution
  • Evolution the change in the genetic composition
    of a population over time due to chance alone
  • Natural Selection the process by which
    mutations create certain traits that are more
    suited to an environment than other traits
  • Adaptation individuals that possess those
    traits that are more suited to the environment
    survive and generally thrive

Concepts surrounding Evolution contd
  • Mutation a random change in the genetic code
  • These mutations lead to the development of new
    traits both helpful and detrimental to a species
  • Charles Darwin was the first to propose these
    concepts voyage of the Beagle in the 1800s

Concepts surrounding Evolution contd
  • Evolution leads to biological diversity
  • Biodiversity is the variety of life in an
    ecosystem or defined area
  • Areas with high biodiversity are called hot
    spots these areas are usually in regions with a
    moderate climate

Biodiversity Hot Spots (red)
Concepts surrounding Evolution contd
  • Speciation leads to many new species several of
    which may be wiped out by an extinction event
  • Extinction causes the disappearance of many
    species but also allows for the evolution of many
    new species
  • Extirpation is the extinction of a species in a
    specific area
  • All past mass extinctions were most likely due to
    catastrophic natural occurrences like Ice ages,
    meteorites, and volcanic eruptions

Levels of Ecological Organization
  • Ecology study of the biotic and abiotic factors
    in an area
  • Species - organisms that look similar and can
    breed to produce reproductively capable offspring
  • Population a group of individuals of the same
    species living together
  • Community - several populations that live in the
    same area

Levels of Ecological Organization contd
  • Ecosystem a defined area with a specific set of
    biotic and abiotic factors usually defined by
    vegetative associations
  • Speciation is demonstrated by using a
    Phylogenetic Tree
  • Habitat versus Niche habitat is where an
    organism lives a niche is how an organism lives
    in its habitat

Levels of Ecological Organization contd
  • Specialist versus Generalist - a specialist
    requires a specific set of resources whereas a
    generalist can live off a broader range of
  • Example Scrub Jay and Raccoon

Population Ecology
  • Population Ecology study of the dynamics of
    populations such as density, distribution, sex
    ratio, age structure, and mortality/natality
  • Population density how many individuals there
    are of a species per unit area
  • Population distribution - spatial arrangement of
    individuals within an area

Population Ecology contd
  • Survivorship curves show the distribution of
    ages across a population predicts the likelihood
    of death at various ages per species

Population Ecology contd
  • Immigration versus Emigration
  • How many enter an area versus how many leave an
  • Formula for Growth Rate
  • (Birth Rate Immigration Rate)
  • (Death Rate Emigration Rate) Growth rate

Population Ecology contd
  • Exponential Growth the global human population
    began to increase exponentially at onset of the
    Industrial Revolution
  • However, now there is a population paradox

Population Ecology contd
  • Population growth is dependent on biotic
  • Some species can reproduce many offspring per
    reproductive event, and can have several
    reproductive events per year
  • Those species that fit into the above-mentioned
    category are r selected mice and rabbits
  • Species that seldom reproduce, and when they do
    reproduce only have one or two offspring are
    k-selected whales and humans

Population Ecology contd
  • Limiting Factor a resource that prevents a
    population from increasing in size
  • Carrying Capacity total number of individuals
    an ecosystem can sustain based on resource
  • Limiting factors can vary from ecosystem to
    ecosystem and populations of different species
    can vary in size within the same ecosystem
  • What are some examples of limiting factors?
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